Articles | Volume 19, issue 12
Research article 24 Jun 2019
Research article | 24 Jun 2019
Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE): emissions of particulate matter and sulfur dioxide from vehicles and brick kilns and their impacts on air quality in the Kathmandu Valley, Nepal
Min Zhong et al.
No articles found.
Lawrence I. Kleinman, Arthur J. Sedlacek III, Kouji Adachi, Peter R. Buseck, Sonya Collier, Manvendra K. Dubey, Anna L. Hodshire, Ernie Lewis, Timothy B. Onasch, Jeffery R. Pierce, John Shilling, Stephen R. Springston, Jian Wang, Qi Zhang, Shan Zhou, and Robert J. Yokelson
Atmos. Chem. Phys., 20, 13319–13341,Short summary
Aerosols from wildfires affect the Earth's temperature by absorbing light or reflecting it back into space. This study investigates time-dependent chemical, microphysical, and optical properties of aerosols generated by wildfires in the Pacific Northwest, USA. Wildfire smoke plumes were traversed by an instrumented aircraft at locations near the fire and up to 3.5 h travel time downwind. Although there was no net aerosol production, aerosol particles grew and became more efficient scatters.
James M. Roberts, Chelsea E. Stockwell, Robert J. Yokelson, Joost de Gouw, Yong Liu, Vanessa Selimovic, Abigail R. Koss, Kanako Sekimoto, Matthew M. Coggon, Bin Yuan, Kyle J. Zarzana, Steven S. Brown, Cristina Santin, Stefan H. Doerr, and Carsten Warneke
Atmos. Chem. Phys., 20, 8807–8826,Short summary
We measured total reactive nitrogen, Nr, in lab fires from western North American fuels, along with measurements of individual nitrogen compounds. We measured the amount of N that gets converted to inactive compounds (avg. 70 %), and the amount that is accounted for by individual species (85 % of remaining N). We provide guidelines for how the reactive nitrogen is distributed among individual compounds such as NOx and ammonia. This will help estimates and predictions of wildfire emissions.
August Andersson, Elena N. Kirillova, Stefano Decesari, Langley DeWitt, Jimmy Gasore, Katherine E. Potter, Ronald G. Prinn, Maheswar Rupakheti, Jean de Dieu Ndikubwimana, Julius Nkusi, and Bonfils Safari
Atmos. Chem. Phys., 20, 4561–4573,Short summary
Large-scale biomass burning events seasonally cover sub-Saharan Africa with air particles. In this study, we find that the concentrations of these particles at a remote mountain site in Rwanda may increase by a factor of 10 during such dry biomass burning periods, with strong implications for the regional climate and human health. These results provide quantitative constraints that could contribute to reducing the large uncertainties regarding the environmental impact of these fires.
Md. Robiul Islam, Thilina Jayarathne, Isobel J. Simpson, Benjamin Werden, John Maben, Ashley Gilbert, Puppala S. Praveen, Sagar Adhikari, Arnico K. Panday, Maheswar Rupakheti, Donald R. Blake, Robert J. Yokelson, Peter F. DeCarlo, William C. Keene, and Elizabeth A. Stone
Atmos. Chem. Phys., 20, 2927–2951,Short summary
The Kathmandu Valley experiences high levels of air pollution. In this study, atmospheric gases and particulate matter were characterized by online and off-line measurements, with an emphasis on understanding their sources. The major sources of particulate matter and trace gases were identified as garbage burning, biomass burning, and vehicles. The majority of secondary organic aerosol was attributed to anthropogenic precursors, while a minority was attributed to biogenic gases.
Lauren T. Fleming, Peng Lin, James M. Roberts, Vanessa Selimovic, Robert Yokelson, Julia Laskin, Alexander Laskin, and Sergey A. Nizkorodov
Atmos. Chem. Phys., 20, 1105–1129,Short summary
We have explored the nature and stability of molecules that give biomass burning smoke its faint brown color. Different types of biomass fuels were burned and the resulting smoke was collected for a detailed chemical analysis. We found that brown molecules in smoke become less colored when they are irradiated by sunlight, but this photobleaching process is very slow. This means that biomass burning smoke will remain brown-colored for a long time and efficiently warm up the atmosphere.
Matthew M. Coggon, Christopher Y. Lim, Abigail R. Koss, Kanako Sekimoto, Bin Yuan, Jessica B. Gilman, David H. Hagan, Vanessa Selimovic, Kyle J. Zarzana, Steven S. Brown, James M. Roberts, Markus Müller, Robert Yokelson, Armin Wisthaler, Jordan E. Krechmer, Jose L. Jimenez, Christopher Cappa, Jesse H. Kroll, Joost de Gouw, and Carsten Warneke
Atmos. Chem. Phys., 19, 14875–14899,Short summary
Wildfire emissions significantly contribute to adverse air quality; however, the chemical processes that lead to hazardous pollutants, such as ozone, are not fully understood. In this study, we describe laboratory experiments where we simulate the atmospheric chemistry of smoke emitted from a range of biomass fuels. We show that certain understudied compounds, such as furans and phenolic compounds, are significant contributors to pollutants formed as a result of typical atmospheric oxidation.
Jiajue Chai, David J. Miller, Eric Scheuer, Jack Dibb, Vanessa Selimovic, Robert Yokelson, Kyle J. Zarzana, Steven S. Brown, Abigail R. Koss, Carsten Warneke, and Meredith Hastings
Atmos. Meas. Tech., 12, 6303–6317,Short summary
Isotopic analysis offers a potential tool to distinguish between sources and interpret transformation pathways of atmospheric species. We applied recently developed techniques in our lab to characterize the isotopic composition of reactive nitrogen species (NOx, HONO, HNO3, pNO3-) in fresh biomass burning emissions. Intercomparison with other techniques confirms the suitability of our methods, allowing for future applications of our techniques in a variety of environments.
Pankaj Sadavarte, Maheswar Rupakheti, Prakash Bhave, Kiran Shakya, and Mark Lawrence
Atmos. Chem. Phys., 19, 12953–12973,Short summary
Emission inventory studies are an important regulatory tool for quantifying the amount of pollutants released in the atmosphere using the fuel consumption and emission rates for different fuels. This study developed an emission inventory over Nepal for 2001–2016 that reveals the changing fuel consumption and subsequently the pollution across different sectors of industrial, transport, agricultural, commercial and residential uses with the use of spatial distribution of anthropogenic activities.
Hansol D. Lee, Chathuri P. Kaluarachchi, Elias S. Hasenecz, Jonic Z. Zhu, Eduard Popa, Elizabeth A. Stone, and Alexei V. Tivanski
Atmos. Meas. Tech., 12, 2033–2042,Short summary
Dry and wet aerosol deposition modes are commonly used to collect particles on a solid substrate for experiments. We demonstrate, using single-particle microscopy and bulk methods, how the substrate-deposited particles with two components can yield the same core–shell morphology but different shell thicknesses depending on the deposition method. Thus we strongly advise future works to use wet deposition when possible to obtain accurate assessment of the single-particle organic volume fraction.
Vanessa Selimovic, Robert J. Yokelson, Gavin R. McMeeking, and Sarah Coefield
Atmos. Chem. Phys., 19, 3905–3926,Short summary
A massive wildfire smoke episode impacted the western US and Canada in summer 2017. We measured CO, other trace gases, PM, BC, and aerosol optical properties at a heavily impacted, ground-based site affected by this event. Brown carbon diminished as smoke aged but was a persistent component of the regional smoke, accounting for about half of aerosol absorption at 401 nm on average. The PM / CO ratios suggested aerosol evaporation was dominant at the surface at smoke ages of up to ~ 1–2 days.
Anusha Priyadarshani Silva Hettiyadura, Ibrahim M. Al-Naiema, Dagen D. Hughes, Ting Fang, and Elizabeth A. Stone
Atmos. Chem. Phys., 19, 3191–3206,Short summary
This study examines anthropogenic influences on secondary organic aerosol at an urban site in Atlanta, Georgia. Organosulfates accounted for 16.5 % of PM2.5 organic carbon and were mostly derived from isoprene. In contrast to a rural forested site, Atlanta's isoprene-derived organosulfate concentrations were 2–6 times higher and accounted for twice as much organic carbon. Insights are provided as to which organosulfates should be measured in future studies and targeted for standard development.
Xin Wan, Shichang Kang, Maheswar Rupakheti, Qianggong Zhang, Lekhendra Tripathee, Junming Guo, Pengfei Chen, Dipesh Rupakheti, Arnico K. Panday, Mark G. Lawrence, Kimitaka Kawamura, and Zhiyuan Cong
Atmos. Chem. Phys., 19, 2725–2747,Short summary
The sources of primary and secondary aerosols in the Hindu Kush–Himalayan–Tibetan Plateau region are not well known. Organic molecular tracers are useful for aerosol source apportionment. The characterization of molecular tracers were first systemically investigated and the contribution from primary and secondary sources to carbonaceous aerosols was estimated in the Kathmandu Valley. Our results demonstrate that biomass burning contributed a significant fraction to OC in the Kathmandu Valley.
H. Langley DeWitt, Jimmy Gasore, Maheswar Rupakheti, Katherine E. Potter, Ronald G. Prinn, Jean de Dieu Ndikubwimana, Julius Nkusi, and Bonfils Safari
Atmos. Chem. Phys., 19, 2063–2078,Short summary
Air quality in rapidly developing East Africa is a growing but understudied concern. We analyzed long-term black carbon, carbon monoxide, and ozone measurements from the remote Rwanda Climate Observatory and found that seasonal regional biomass burning raised black carbon levels to above-urban concentrations 6 months out of the year. Additional local pollution could exacerbate this issue. More regional monitoring needs to be done to understand and reduce air pollution in this region.
Coty N. Jen, Lindsay E. Hatch, Vanessa Selimovic, Robert J. Yokelson, Robert Weber, Arantza E. Fernandez, Nathan M. Kreisberg, Kelley C. Barsanti, and Allen H. Goldstein
Atmos. Chem. Phys., 19, 1013–1026,Short summary
Wildfires in the western US are occurring more frequently and burning larger land areas. Smoke from these fires will play a greater role in regional air quality and atmospheric chemistry than in the past. To help fire and climate modelers and atmospheric experimentalists better understand how smoke impacts the environment, we have separated, identified, classified, and quantified the thousands of organic compounds found in smoke and related their amounts emitted to fire conditions.
Ashish Singh, Khadak S. Mahata, Maheswar Rupakheti, Wolfgang Junkermann, Arnico K. Panday, and Mark G. Lawrence
Atmos. Chem. Phys., 19, 245–258,Short summary
This paper reports the first airborne measurement campaign in the central Himalayan foothill region, one of the polluted but relatively poorly sampled regions of the world. The measurement campaign quantifies the vertical distribution of aerosols over a polluted mountain valley in the Himalayan foothills and investigates the extent of regional emission transport.
Ibrahim M. Al-Naiema, Anusha P. S. Hettiyadura, Henry W. Wallace, Nancy P. Sanchez, Carter J. Madler, Basak Karakurt Cevik, Alexander A. T. Bui, Josh Kettler, Robert J. Griffin, and Elizabeth A. Stone
Atmos. Chem. Phys., 18, 15601–15622,Short summary
By integrating newly developed tracers for anthropogenic secondary organic aerosol in source apportionment for the first time, we estimate that this source contributes 28 % of fine particle organic carbon in the Houston Ship Channel. Our approach can be used to evaluate anthropogenic, biogenic, and biomass burning contributions to secondary organic aerosols elsewhere in the world. Because anthropogenic emissions are potentially controllable, they provide an opportunity to improve air quality.
Kyle J. Zarzana, Vanessa Selimovic, Abigail R. Koss, Kanako Sekimoto, Matthew M. Coggon, Bin Yuan, William P. Dubé, Robert J. Yokelson, Carsten Warneke, Joost A. de Gouw, James M. Roberts, and Steven S. Brown
Atmos. Chem. Phys., 18, 15451–15470,Short summary
Emissions of glyoxal and methylglyoxal from fuels common to the western United States were measured using cavity-enhanced spectroscopy, which provides a more selective measurement of those compounds than was previously available. Primary emissions of glyoxal were lower than previously reported and showed variability between the different fuel groups. However, emissions of glyoxal relative to formaldehyde were constant across almost all the fuel groups at 6 %–7 %.
J. Douglas Goetz, Michael R. Giordano, Chelsea E. Stockwell, Ted J. Christian, Rashmi Maharjan, Sagar Adhikari, Prakash V. Bhave, Puppala S. Praveen, Arnico K. Panday, Thilina Jayarathne, Elizabeth A. Stone, Robert J. Yokelson, and Peter F. DeCarlo
Atmos. Chem. Phys., 18, 14653–14679,Short summary
Size distributions and emission factors of submicron aerosol were quantified using online techniques for a variety of common but under-sampled combustion sources in South Asia: wood and dung cooking fires, groundwater pumps, brick kilns, trash burning, and open burning of crop residues. Optical properties (brown carbon light absorption and the absorption Ångström exponent, AAE) of the emissions were also investigated. Contextual comparisons to the literature and other NAMaSTE results were made.
Khadak Singh Mahata, Maheswar Rupakheti, Arnico Kumar Panday, Piyush Bhardwaj, Manish Naja, Ashish Singh, Andrea Mues, Paolo Cristofanelli, Deepak Pudasainee, Paolo Bonasoni, and Mark G. Lawrence
Atmos. Chem. Phys., 18, 14113–14132,Short summary
This paper presents the first-time simultaneous measurement of CO and O3 at multiple sites in the Kathmandu Valley bottom, its mountain rim and a river outlet, providing their spatial, temporal and seasonal–diurnal variations. Our study reveals that high O3, especially during premonsoon, in observed sites is of high concern for human health and ecosystems in the region. We also estimated CO emission flux to be 2–14 times higher than widely used emission databases (EDGAR HTAP, REAS and INTEX-B).
Piyush Bhardwaj, Manish Naja, Maheswar Rupakheti, Aurelia Lupascu, Andrea Mues, Arnico Kumar Panday, Rajesh Kumar, Khadak Singh Mahata, Shyam Lal, Harish C. Chandola, and Mark G. Lawrence
Atmos. Chem. Phys., 18, 11949–11971,Short summary
This study provides information about the regional variabilities in some of the pollutants using observations in Nepal and India. It is shown that agricultural crop residue burning leads to a significant enhancement in ozone and CO over a wider region. Further, the wintertime higher ozone levels are shown to be largely due to local emissions, while regional transport could be important in spring and hence shows the role of regional sources versus local sources in the Kathmandu Valley.
Prasad Kasibhatla, Tomás Sherwen, Mathew J. Evans, Lucy J. Carpenter, Chris Reed, Becky Alexander, Qianjie Chen, Melissa P. Sulprizio, James D. Lee, Katie A. Read, William Bloss, Leigh R. Crilley, William C. Keene, Alexander A. P. Pszenny, and Alma Hodzic
Atmos. Chem. Phys., 18, 11185–11203,Short summary
Recent measurements of NOx and HONO suggest that photolysis of particulate nitrate in sea-salt aerosols is important in terms of marine boundary layer oxidant chemistry. We present the first global-scale assessment of the significance of this new chemical pathway for NOx, O3, and OH in the marine boundary layer. We also present a preliminary assessment of the potential impact of photolysis of particulate nitrate associated with other aerosol types on continental boundary layer chemistry.
Kanako Sekimoto, Abigail R. Koss, Jessica B. Gilman, Vanessa Selimovic, Matthew M. Coggon, Kyle J. Zarzana, Bin Yuan, Brian M. Lerner, Steven S. Brown, Carsten Warneke, Robert J. Yokelson, James M. Roberts, and Joost de Gouw
Atmos. Chem. Phys., 18, 9263–9281,Short summary
We found that on average 85 % of the VOC emissions from biomass burning across various fuels representative of the western US (including various coniferous and chaparral fuels) can be explained using only two emission profiles: (i) a high-temperature pyrolysis profile and (ii) a low-temperature pyrolysis profile. The high-temperature profile is quantitatively similar between different fuel types (r2 > 0.84), and likewise for the low-temperature profile.
Andrea Mues, Axel Lauer, Aurelia Lupascu, Maheswar Rupakheti, Friderike Kuik, and Mark G. Lawrence
Geosci. Model Dev., 11, 2067–2091,
Chelsea E. Stockwell, Agnieszka Kupc, Bartłomiej Witkowski, Ranajit K. Talukdar, Yong Liu, Vanessa Selimovic, Kyle J. Zarzana, Kanako Sekimoto, Carsten Warneke, Rebecca A. Washenfelder, Robert J. Yokelson, Ann M. Middlebrook, and James M. Roberts
Atmos. Meas. Tech., 11, 2749–2768,Short summary
This work investigates the total conversion of particle-bound nitrogen and organic carbon across platinum and molybdenum catalysts followed by NO–O3 chemiluminescence and nondispersive infrared CO2 detection. We show the instrument is an accurate particle mass measurement method and demonstrate its ability to calibrate particle mass measurement instrumentation through comparisons with a calibrated particle-into-liquid sampler coupled to an electrospray ionization source of a mass spectrometer.
D. Rupakheti, S. Kang, Z. Cong, M. Rupakheti, L. Tripathee, A. K. Panday, and B. Holben
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLII-3, 1493–1497,
Abigail R. Koss, Kanako Sekimoto, Jessica B. Gilman, Vanessa Selimovic, Matthew M. Coggon, Kyle J. Zarzana, Bin Yuan, Brian M. Lerner, Steven S. Brown, Jose L. Jimenez, Jordan Krechmer, James M. Roberts, Carsten Warneke, Robert J. Yokelson, and Joost de Gouw
Atmos. Chem. Phys., 18, 3299–3319,Short summary
Non-methane organic gases (NMOGs) were detected by proton-transfer-reaction mass spectrometry (PTR-ToF) during an extensive laboratory characterization of wildfire emissions. Identifications for PTR-ToF ion masses are proposed and supported by a combination of techniques. Overall excellent agreement with other instrumentation is shown. Scalable emission factors and ratios are reported for many newly reported reactive species. An analysis of chemical characteristics is presented.
Vanessa Selimovic, Robert J. Yokelson, Carsten Warneke, James M. Roberts, Joost de Gouw, James Reardon, and David W. T. Griffith
Atmos. Chem. Phys., 18, 2929–2948,Short summary
We burned fuels representing western US wildfires in large-scale laboratory simulations to generate relevant emissions as confirmed by lab–field comparison. We report emission factors (EFs) for light scattering and absorption and BC along with SSA at 870 and 401 nm and AAE. We report EF for 22 trace gases that are major inorganic and organic emissions from flaming and smoldering. We report trace gas EF for species rarely (NH3) or not yet measured (e.g., HONO, acetic acid) for real US wildfires.
Thilina Jayarathne, Chelsea E. Stockwell, Ashley A. Gilbert, Kaitlyn Daugherty, Mark A. Cochrane, Kevin C. Ryan, Erianto I. Putra, Bambang H. Saharjo, Ati D. Nurhayati, Israr Albar, Robert J. Yokelson, and Elizabeth A. Stone
Atmos. Chem. Phys., 18, 2585–2600,Short summary
Fine particulate matter (PM2.5) emissions from Indonesian peat burning were measured in situ. Fuel-based emission factors from 6.0–29.6 gPM kg-1. Detailed chemical analysis revealed high levels of organic carbon that was primarily water insoluble, little to no detectable elemental carbon, and alkane contributions to organic carbon in the range of 6 %. These data were used to estimate that 3.2–11 Tg of PM2.5 were emitted by the 2015 peat burning episodes in Indonesia.
Thilina Jayarathne, Chelsea E. Stockwell, Prakash V. Bhave, Puppala S. Praveen, Chathurika M. Rathnayake, Md. Robiul Islam, Arnico K. Panday, Sagar Adhikari, Rashmi Maharjan, J. Douglas Goetz, Peter F. DeCarlo, Eri Saikawa, Robert J. Yokelson, and Elizabeth A. Stone
Atmos. Chem. Phys., 18, 2259–2286,Short summary
Emissions of fine particulate matter and its constituents were quantified for a variety of under-sampled combustion sources in South Asia: wood and dung cooking fires, generators, groundwater pumps, brick kilns, trash burning, and open burning of biomasses. Garbage burning and three-stone cooking fires were among the highest emitters, while servicing of motor vehicles significantly reduced PM. These data may be used in source apportionment and to update regional and global emission inventories.
Katherine M. Manfred, Rebecca A. Washenfelder, Nicholas L. Wagner, Gabriela Adler, Frank Erdesz, Caroline C. Womack, Kara D. Lamb, Joshua P. Schwarz, Alessandro Franchin, Vanessa Selimovic, Robert J. Yokelson, and Daniel M. Murphy
Atmos. Chem. Phys., 18, 1879–1894,Short summary
In this study, we use a new laser imaging nephelometer to measure the bulk aerosol scattering phase function for biomass burning aerosol from controlled fires. By comparing measurements to models for spherical and fractal particles, we demonstrate that the dominant morphology varies by fuel type. This instrument has unique capabilities to directly measure how morphology affects optical properties, and can be used in the future for important validations of remote sensing retrievals.
Shradda Dhungel, Bhogendra Kathayat, Khadak Mahata, and Arnico Panday
Atmos. Chem. Phys., 18, 1203–1216,Short summary
We analyze seasonal and diurnal concentrations of black carbon (BC), ozone, and associated meteorological conditions within a remote trans-Himalayan valley in western Nepal. We observe elevated BC concentrations during non-monsoon seasons, frequent and persistent episodes of higher-than-average concentrations, and net up-valley fluxes throughout the year. The findings provide direct observational evidence of trans-Himalayan valleys serving as vital pollutant transport pathways.
Kelley C. Wells, Dylan B. Millet, Nicolas Bousserez, Daven K. Henze, Timothy J. Griffis, Sreelekha Chaliyakunnel, Edward J. Dlugokencky, Eri Saikawa, Gao Xiang, Ronald G. Prinn, Simon O'Doherty, Dickon Young, Ray F. Weiss, Geoff S. Dutton, James W. Elkins, Paul B. Krummel, Ray Langenfelds, and L. Paul Steele
Atmos. Chem. Phys., 18, 735–756,Short summary
This paper uses three different frameworks to derive nitrous oxide (N2O) emissions based on global surface observations. One of these frameworks employs a new approach that allows for fast computation and explores a larger solution space than other methods. Our results point to a few conclusions about the global N2O budget, including a larger contribution from tropical sources, an overestimate of natural soil emissions, and an underestimate of agricultural sources particularly in springtime.
Khadak Singh Mahata, Arnico Kumar Panday, Maheswar Rupakheti, Ashish Singh, Manish Naja, and Mark G. Lawrence
Atmos. Chem. Phys., 17, 12573–12596,Short summary
The paper provides an overview of CH4, CO2, and CO mixing ratios, including diurnal and seasonal variation, and discusses the association of potential sources and meteorology with the observed temporal variation in the Kathmandu Valley. The study will provide an important dataset for a poorly studied region and will be useful for validating estimates from emission inventories, regional models, and satellite observations and assisting in the design of mitigation measures in the region.
Chaeyoon Cho, Sang-Woo Kim, Maheswar Rupakheti, Jin-Soo Park, Arnico Panday, Soon-Chang Yoon, Ji-Hyoung Kim, Hyunjae Kim, Haeun Jeon, Minyoung Sung, Bong Mann Kim, Seungkyu K. Hong, Rokjin J. Park, Dipesh Rupakheti, Khadak Singh Mahata, Puppala Siva Praveen, Mark G. Lawrence, and Brent Holben
Atmos. Chem. Phys., 17, 12617–12632,Short summary
We investigated the optical and chemical properties and direct radiative effects of aerosols in the Kathmandu Valley. We concluded that the ratio of light-absorbing to scattering aerosols as well as the concentration of light-absorbing aerosols is much higher at Kathmandu than other comparable regions, and it contributes to a great atmospheric absorption efficiency. This study provides unprecedented insights into aerosol optical properties and their radiative forcings in the Kathmandu Valley.
Dipesh Rupakheti, Bhupesh Adhikary, Puppala Siva Praveen, Maheswar Rupakheti, Shichang Kang, Khadak Singh Mahata, Manish Naja, Qianggong Zhang, Arnico Kumar Panday, and Mark G. Lawrence
Atmos. Chem. Phys., 17, 11041–11063,Short summary
For the first time, atmospheric composition was monitored during pre-monsoon season of 2013 at Lumbini (UNESCO world heritage site as birthplace of the Buddha). PM and O3 frequently exceeded WHO guidelines. Pollution concentration, diurnal characteristics and influence of open burning on air quality in Lumbini were investigated. Potential source regions were also identified. Results show that air pollution at this site is of a great concern, requiring prompt attention for mitigation.
Guido R. van der Werf, James T. Randerson, Louis Giglio, Thijs T. van Leeuwen, Yang Chen, Brendan M. Rogers, Mingquan Mu, Margreet J. E. van Marle, Douglas C. Morton, G. James Collatz, Robert J. Yokelson, and Prasad S. Kasibhatla
Earth Syst. Sci. Data, 9, 697–720,Short summary
Fires occur in many vegetation types and are sometimes natural but often ignited by humans for various purposes. We have estimated how much area they burn globally and what their emissions are. Total burned area is roughly equivalent to the size of the EU with most fires burning in tropical savannas. Their emissions vary substantially from year to year and contribute to the atmospheric burdens of many trace gases and aerosols. The 20-year dataset is mostly suited for large-scale assessments.
Xin Wan, Shichang Kang, Quanlian Li, Dipesh Rupakheti, Qianggong Zhang, Junming Guo, Pengfei Chen, Lekhendra Tripathee, Maheswar Rupakheti, Arnico K. Panday, Wu Wang, Kimitaka Kawamura, Shaopeng Gao, Guangming Wu, and Zhiyuan Cong
Atmos. Chem. Phys., 17, 8867–8885,Short summary
Biomass burning (BB) tracers in the aerosols in Lumbini, northern IGP, were studied for the first time. The levoglucosan was the predominant tracer and BB significantly contributed to the air quality in Lumbini. Mixed crop residues and hardwood were main burning materials. BB emissions constituted large fraction of OC, especially during the post-monsoon season. The sources of BB aerosols in Lumbini varies seasonally due to the influence of local emissions and long-range transport.
Andrea Mues, Maheswar Rupakheti, Christoph Münkel, Axel Lauer, Heiko Bozem, Peter Hoor, Tim Butler, and Mark G. Lawrence
Atmos. Chem. Phys., 17, 8157–8176,Short summary
Ceilometer measurements taken in the Kathmandu Valley, Nepal, were used to study the temporal and spatial evolution of the mixing layer height in the valley. This provides important information on the vertical structure of the atmosphere and can thus also help to understand the mixing of air pollutants (e.g. black carbon) in the valley. The seasonal and diurnal cycles of the mixing layer were found to be highly dependent on meteorology and mainly anticorrelated to black carbon concentrations.
Chinmoy Sarkar, Vinayak Sinha, Baerbel Sinha, Arnico K. Panday, Maheswar Rupakheti, and Mark G. Lawrence
Atmos. Chem. Phys., 17, 8129–8156,Short summary
This study provides quantitative information regarding the source contributions of the major non-methane volatile organic compound sources in the Kathmandu Valley. Combining high-resolution in situ NMVOC data and model analyses, we show that REAS v2.1 and EDGAR v4.2 emission inventories underestimate the contribution of traffic and do not take the contribution of brick kilns into account. Furthermore, REAS v2.1 overestimates the contribution of residential biofuel use and industries.
Kabindra M. Shakya, Maheswar Rupakheti, Anima Shahi, Rejina Maskey, Bidya Pradhan, Arnico Panday, Siva P. Puppala, Mark Lawrence, and Richard E. Peltier
Atmos. Chem. Phys., 17, 6503–6516,Short summary
Particulate matter levels were monitored at six major roadway intersections in the Kathmandu Valley during two seasons in 2014. The study documented distinct seasonal (dry season versus wet season) and diel variations in particulate matter levels. This study suggests traffic-related emissions, and soil–dust–construction materials were found to be a major source of particulate matter at these locations.
Eri Saikawa, Hankyul Kim, Min Zhong, Alexander Avramov, Yu Zhao, Greet Janssens-Maenhout, Jun-ichi Kurokawa, Zbigniew Klimont, Fabian Wagner, Vaishali Naik, Larry W. Horowitz, and Qiang Zhang
Atmos. Chem. Phys., 17, 6393–6421,Short summary
We analyze differences in existing air pollutant emission estimates to better understand the magnitude of emissions as well as the source regions and sectors of air pollution in China. We find large disagreements among the inventories, and we show that these differences have a significant impact on regional air quality simulations. Better understanding of air pollutant emissions at more disaggregated levels is essential for air pollution mitigation in China.
Sujan Shrestha, Siva Praveen Puppala, Bhupesh Adhikary, Kundan Lal Shrestha, and Arnico K. Panday
Atmos. Chem. Phys. Discuss.,
Revised manuscript not accepted
Rudra P. Pokhrel, Eric R. Beamesderfer, Nick L. Wagner, Justin M. Langridge, Daniel A. Lack, Thilina Jayarathne, Elizabeth A. Stone, Chelsea E. Stockwell, Robert J. Yokelson, and Shane M. Murphy
Atmos. Chem. Phys., 17, 5063–5078,Short summary
This study investigates enhancement of black carbon (BC) absorption in biomass burning emissions due to absorbing and non-absorbing coatings. The fraction of absorption due to BC, brown carbon (BrC), and lensing is estimated using different approaches. The similarities and differences between the results from these approaches are discussed. Absorption by BrC is shown to have good correlation with the elemental to organic carbon ratio (EC / OC) and AAE.
Chathurika M. Rathnayake, Nervana Metwali, Thilina Jayarathne, Josh Kettler, Yuefan Huang, Peter S. Thorne, Patrick T. O'Shaughnessy, and Elizabeth A. Stone
Atmos. Chem. Phys., 17, 2459–2475,Short summary
Exposures to bioaerosols depend on their type, particle size, and concentration. While typically found in coarse particles (2.5–10 microns), pollens, fungal spores, and bacterial endotoxins decrease to less than 2.5 microns and simultaneously increase in concentration during rain events. These observations contrast the assumption that rain washes bioaerosols from the air and reduces allergen levels. Instead, population exposures to bioaerosols are expected to be enhanced during rain events.
Ibrahim M. Al-Naiema and Elizabeth A. Stone
Atmos. Chem. Phys., 17, 2053–2065,Short summary
Molecular tracers have proven useful in estimating contributions of primary and biogenic secondary sources to atmospheric particulate matter but have lagged behind for anthropogenic secondary sources. This study takes a field-based approach to evaluate the detectability, specificity, and gas–particle partitioning of prospective anthropogenic SOA tracers. We conclude that a subset of species are likely useful tracers and are recommended for use in future source apportionment studies.
Lindsay E. Hatch, Robert J. Yokelson, Chelsea E. Stockwell, Patrick R. Veres, Isobel J. Simpson, Donald R. Blake, John J. Orlando, and Kelley C. Barsanti
Atmos. Chem. Phys., 17, 1471–1489,Short summary
The most comprehensive database of gaseous biomass burning emissions to date was compiled. Four complementary instruments were deployed together during laboratory fires. The results generally compared within experimental uncertainty and highlighted that a range of measurement approaches are required for adequate characterization of smoke composition. Observed compounds were binned based on volatility, and priority recommendations were made to improve secondary organic aerosol predictions.
Anusha P. S. Hettiyadura, Thilina Jayarathne, Karsten Baumann, Allen H. Goldstein, Joost A. de Gouw, Abigail Koss, Frank N. Keutsch, Kate Skog, and Elizabeth A. Stone
Atmos. Chem. Phys., 17, 1343–1359,Short summary
Organosulfates are components of secondary organic aerosol (SOA) formed in the presence of sulfate. Herein, their abundance, identity, and potential to form as sampling artifacts were studied in Centreville, AL, USA. The 10 most abundant signals accounted for 58–78 % of the total, with at least 20–200 other species accounting for the remainder. These major species were largely associated with biogenic gases, like isoprene and monoterpenes, and are proposed targets for future standard development.
Marie Ila Gosselin, Chathurika M. Rathnayake, Ian Crawford, Christopher Pöhlker, Janine Fröhlich-Nowoisky, Beatrice Schmer, Viviane R. Després, Guenter Engling, Martin Gallagher, Elizabeth Stone, Ulrich Pöschl, and J. Alex Huffman
Atmos. Chem. Phys., 16, 15165–15184,Short summary
We present an analysis of bioaerosol measurements using two real-time fluorescence instruments in combination with molecular tracer techniques for quantifying airborne fungal spores in a semi-arid forest. Both techniques provide fungal spore concentrations of the order of 104 m−3 and up to 30 % of particle mass. Rainy periods exhibited higher concentrations and stronger correlations between fluorescent bioparticle and molecular tracer measurements. Fungal culture results are also presented.
Chelsea E. Stockwell, Thilina Jayarathne, Mark A. Cochrane, Kevin C. Ryan, Erianto I. Putra, Bambang H. Saharjo, Ati D. Nurhayati, Israr Albar, Donald R. Blake, Isobel J. Simpson, Elizabeth A. Stone, and Robert J. Yokelson
Atmos. Chem. Phys., 16, 11711–11732,Short summary
We present the first or rare field measurements of emission factors for Indonesian peat fires made in Borneo during the 2015 El Niño. The data include up to 90 gases, aerosol mass, and aerosol optical properties at two wavelengths (405 and 870 nm). Brown carbon dominates aerosol absorption, revisions to previous values for greenhouse gas emissions are supported and air toxics are assessed.
Chelsea E. Stockwell, Ted J. Christian, J. Douglas Goetz, Thilina Jayarathne, Prakash V. Bhave, Puppala S. Praveen, Sagar Adhikari, Rashmi Maharjan, Peter F. DeCarlo, Elizabeth A. Stone, Eri Saikawa, Donald R. Blake, Isobel J. Simpson, Robert J. Yokelson, and Arnico K. Panday
Atmos. Chem. Phys., 16, 11043–11081,Short summary
We present the first, or rare, field measurements in South Asia of emission factors for up to 80 gases (pollutants, greenhouse gases, and precursors) and black carbon and aerosol optical properties at 405 and 870 nm for many previously under-sampled sources that are important in developing countries such as cooking with dung and wood, garbage and crop residue burning, brick kilns, motorcycles, generators and pumps, etc. Brown carbon contributes significantly to total aerosol absorption.
Matthieu Riva, Thais Da Silva Barbosa, Ying-Hsuan Lin, Elizabeth A. Stone, Avram Gold, and Jason D. Surratt
Atmos. Chem. Phys., 16, 11001–11018,Short summary
Formation of organosulfates (OSs) in secondary organic aerosol from the photooxidation of alkanes is reported from smog chamber experiments. Effects of acidity and relative humidity on OS formation were examined. Most of the OSs identified could be explained by formation of gaseous epoxide and/or hydroperoxide precursors with subsequent acid-catalyzed multiphase chemistry onto sulfate aerosol. The OSs identified here were also observed and quantified in aerosols collected in two urban areas.
Rudra P. Pokhrel, Nick L. Wagner, Justin M. Langridge, Daniel A. Lack, Thilina Jayarathne, Elizabeth A. Stone, Chelsea E. Stockwell, Robert J. Yokelson, and Shane M. Murphy
Atmos. Chem. Phys., 16, 9549–9561,Short summary
This paper gives first multi-wavelength estimates of SSA and AAE of emissions from combustion of Indonesian peat. In addition, it demonstrates that SSA of biomass burning emissions can be parameterized with EC / (EC+OC) and that this parameterization is quantitatively superior to previously published parameterizations based on MCE. It also shows that EC / (EC+OC) parameterization accurately predicts SSA during the first few hours of aging of a biomass burning plume.
R. Hossaini, P. K. Patra, A. A. Leeson, G. Krysztofiak, N. L. Abraham, S. J. Andrews, A. T. Archibald, J. Aschmann, E. L. Atlas, D. A. Belikov, H. Bönisch, L. J. Carpenter, S. Dhomse, M. Dorf, A. Engel, W. Feng, S. Fuhlbrügge, P. T. Griffiths, N. R. P. Harris, R. Hommel, T. Keber, K. Krüger, S. T. Lennartz, S. Maksyutov, H. Mantle, G. P. Mills, B. Miller, S. A. Montzka, F. Moore, M. A. Navarro, D. E. Oram, K. Pfeilsticker, J. A. Pyle, B. Quack, A. D. Robinson, E. Saikawa, A. Saiz-Lopez, S. Sala, B.-M. Sinnhuber, S. Taguchi, S. Tegtmeier, R. T. Lidster, C. Wilson, and F. Ziska
Atmos. Chem. Phys., 16, 9163–9187,
Weruka Rattanavaraha, Kevin Chu, Sri Hapsari Budisulistiorini, Matthieu Riva, Ying-Hsuan Lin, Eric S. Edgerton, Karsten Baumann, Stephanie L. Shaw, Hongyu Guo, Laura King, Rodney J. Weber, Miranda E. Neff, Elizabeth A. Stone, John H. Offenberg, Zhenfa Zhang, Avram Gold, and Jason D. Surratt
Atmos. Chem. Phys., 16, 4897–4914,Short summary
The mechanisms by which specific anthropogenic pollutants enhance isoprene SOA in ambient PM2.5 remain unclear. As one aspect of an investigation to examine how anthropogenic pollutants influence isoprene-derived SOA formation, high-volume PM2.5 filter samples were collected from Birmingham, AL, during the 2013 Southern Oxidant and Aerosol Study (SOAS). Isoprene SOA tracers were measured from these samples and compared to gas and aerosol data collected from the SEARCH network.
Min Zhong, Eri Saikawa, Yang Liu, Vaishali Naik, Larry W. Horowitz, Masayuki Takigawa, Yu Zhao, Neng-Huei Lin, and Elizabeth A. Stone
Geosci. Model Dev., 9, 1201–1218,Short summary
Large discrepancies exist among emission inventories (e.g., REAS and EDGAR) at the provincial level in China. We use WRF-Chem to evaluate the impact of the difference in existing emission inventories and find that emissions inputs significantly affect our air pollutant simulation results. Our study highlights the importance of constraining emissions at the provincial level for regional air quality modeling over East Asia.
Chinmoy Sarkar, Vinayak Sinha, Vinod Kumar, Maheswar Rupakheti, Arnico Panday, Khadak S. Mahata, Dipesh Rupakheti, Bhogendra Kathayat, and Mark G. Lawrence
Atmos. Chem. Phys., 16, 3979–4003,Short summary
First deployment of PTR-TOF-MS in South Asia. High acetaldehyde and biogenic isoprene concentrations detected even in winter in the Kathmandu Valley. Isocyanic acid, formamide, acetamide, naphthalene and nitromethane were detected for the first time in South Asian air. Oxygenated VOCs and isoprene-dominated OH reactivity and ozone production potentials (> 68 % OPP). Regulation of emissions from biomass co-fired brick kilns' by cleaner technology would improve air quality of the valley.
Markus Müller, Bruce E. Anderson, Andreas J. Beyersdorf, James H. Crawford, Glenn S. Diskin, Philipp Eichler, Alan Fried, Frank N. Keutsch, Tomas Mikoviny, Kenneth L. Thornhill, James G. Walega, Andrew J. Weinheimer, Melissa Yang, Robert J. Yokelson, and Armin Wisthaler
Atmos. Chem. Phys., 16, 3813–3824,Short summary
Atmospheric emissions from small forest fires and their impact on regional air quality are still poorly characterized. We used an instrumented NASA P-3B aircraft to study emissions from a small forest understory fire in Georgia (USA) and to investigate chemical transformations in the fire plume in the 1 h downwind region. A state-of-the-art chemical model was able to accurately simulate key chemical processes in the aging plume.
Peng Fei Chen, Chao Liu Li, Shi Chang Kang, Maheswar Rupakheti, Arnico K. Panday, Fang Ping Yan, Quan Lian Li, Qiang Gong Zhang, Jun Ming Guo, Dipesh Rupakheti, and Wei Luo
Atmos. Chem. Phys. Discuss.,
Revised manuscript not acceptedShort summary
PAHs were measured at six sites along two south-north transects across the central Himalayas. The annual average PAHs and their dry deposition fluxes decreased noticeably from the south to north sides, however, a similar compostion pattern was found at three remote sites, suggesting the northern slope of the Himalayas may be affected by anthropogenic emissions form Indo-Gangetic Plain. PAHs showed a clear seasonal variation at Nepal and they were mainly form biomass and fossil combustion .
E. W. Butt, A. Rap, A. Schmidt, C. E. Scott, K. J. Pringle, C. L. Reddington, N. A. D. Richards, M. T. Woodhouse, J. Ramirez-Villegas, H. Yang, V. Vakkari, E. A. Stone, M. Rupakheti, P. S. Praveen, P. G. van Zyl, J. P. Beukes, M. Josipovic, E. J. S. Mitchell, S. M. Sallu, P. M. Forster, and D. V. Spracklen
Atmos. Chem. Phys., 16, 873–905,Short summary
We estimate the impact of residential emissions (cooking and heating) on atmospheric aerosol, human health, and climate. We find large contributions to annual mean ambient PM2.5 in residential sources regions resulting in significant but uncertain global premature mortality when key uncertainties in emission flux are considered. We show that residential emissions exert an uncertain global radiative effect and suggest more work is needed to characterise residential emissions climate importance.
J. B. Gilman, B. M. Lerner, W. C. Kuster, P. D. Goldan, C. Warneke, P. R. Veres, J. M. Roberts, J. A. de Gouw, I. R. Burling, and R. J. Yokelson
Atmos. Chem. Phys., 15, 13915–13938,Short summary
A comprehensive suite of instruments was used to quantify the emissions of over 200 organic and inorganic gases from 56 laboratory burns of 18 different biomass fuel types common in the southeastern, southwestern, or northern United States. Emission ratios relative to carbon monoxide (CO) are used to characterize the composition of gases emitted by mass; OH reactivity; and potential secondary organic aerosol (SOA) precursors for the three different U.S. fuel regions presented here.
D. Putero, P. Cristofanelli, A. Marinoni, B. Adhikary, R. Duchi, S. D. Shrestha, G. P. Verza, T. C. Landi, F. Calzolari, M. Busetto, G. Agrillo, F. Biancofiore, P. Di Carlo, A. K. Panday, M. Rupakheti, and P. Bonasoni
Atmos. Chem. Phys., 15, 13957–13971,Short summary
The aim of this paper is to present a full-year analysis of simultaneous measurements of ozone, black carbon, and aerosol number concentration at Paknajol, in the Kathmandu Valley, one of the global “hot spots” in terms of air pollution. Results indicate persisting poor air quality conditions throughout the measurement period, and suggest that the pollutants' variability is mainly driven by local pollution source activity, local- and large-scale dynamics, photochemistry, and vegetation fires.
S. H. Budisulistiorini, X. Li, S. T. Bairai, J. Renfro, Y. Liu, Y. J. Liu, K. A. McKinney, S. T. Martin, V. F. McNeill, H. O. T. Pye, A. Nenes, M. E. Neff, E. A. Stone, S. Mueller, C. Knote, S. L. Shaw, Z. Zhang, A. Gold, and J. D. Surratt
Atmos. Chem. Phys., 15, 8871–8888,Short summary
Isoprene epoxydiols (IEPOX) are major gas-phase products from the atmospheric oxidation of isoprene that yield secondary organic aerosol (SOA) by reactive uptake onto acidic sulfate aerosol. We report a substantial contribution of IEPOX-derived SOA to the total fine aerosol collected during summer. IEPOX-derived SOA measured by online and offline mass spectrometry techniques is correlated with acidic sulfate aerosol, demonstrating the critical role of anthropogenic emissions in its formation.
M. J. Alvarado, C. R. Lonsdale, R. J. Yokelson, S. K. Akagi, H. Coe, J. S. Craven, E. V. Fischer, G. R. McMeeking, J. H. Seinfeld, T. Soni, J. W. Taylor, D. R. Weise, and C. E. Wold
Atmos. Chem. Phys., 15, 6667–6688,Short summary
Being able to understand and simulate the chemical evolution of biomass burning smoke plumes under a wide variety of conditions is a critical part of forecasting the impact of these fires on air quality, atmospheric composition, and climate. Here we use an improved model of this chemistry to simulate the evolution of ozone and secondary organic aerosol within a young biomass burning smoke plume from the Williams prescribed burn in chaparral, which was sampled over California in November 2009.
A. A. May, T. Lee, G. R. McMeeking, S. Akagi, A. P. Sullivan, S. Urbanski, R. J. Yokelson, and S. M. Kreidenweis
Atmos. Chem. Phys., 15, 6323–6335,Short summary
Smoke plumes from some prescribed fires in the southeastern United States were sampled via aircraft to observe changes in organic aerosol (OA) with atmospheric transport. These plumes underwent rapid mixing, and, hence, substantial dilution with background air occurred. Dilution-driven evaporation appears to be the primary driver of OA transformations within the sampled plumes rather than photochemistry.
A. P. S. Hettiyadura, E. A. Stone, S. Kundu, Z. Baker, E. Geddes, K. Richards, and T. Humphry
Atmos. Meas. Tech., 8, 2347–2358,Short summary
Organosulfates are SOA products that have proven difficult to quantify. This study addresses the need for authentic quantification standards with a straightforward approach to synthesizing highly pure organosulfate potassium salts. New standards are used to develop a new separation protocol for small, functionalized organosulfates. Upon validation, this method is used to assess sample preparation protocols and to make new measurements of organosulfates in Centreville, Alabama.
Z. L. Lüthi, B. Škerlak, S.-W. Kim, A. Lauer, A. Mues, M. Rupakheti, and S. Kang
Atmos. Chem. Phys., 15, 6007–6021,Short summary
The Himalayas and the Tibetan Plateau region (HTP) is regularly exposed to polluted air masses that might influence glaciers as well as climate on regional to global scales. We found that atmospheric brown clouds from South Asia reach the HTP by crossing the Himalayas not only through the major north--south river valleys but rather over large areas by being lifted and advected at mid-troposheric levels. The transport is enabled by a combination of synoptic and local meteorological settings.
L. Drinovec, G. Močnik, P. Zotter, A. S. H. Prévôt, C. Ruckstuhl, E. Coz, M. Rupakheti, J. Sciare, T. Müller, A. Wiedensohler, and A. D. A. Hansen
Atmos. Meas. Tech., 8, 1965–1979,Short summary
We present a new real-time algorithm for compensation of the filter-loading effect in filter photometers, based on a two parallel spot measurement of optical absorption. This algorithm has been incorporated into the new Aethalometer AE33. Intercomparison studies show excellent reproducibility of the AE33 measurements and very good agreement with post-processed data obtained using earlier aethalometer models and other filter-based absorption photometers.
L. E. Hatch, W. Luo, J. F. Pankow, R. J. Yokelson, C. E. Stockwell, and K. C. Barsanti
Atmos. Chem. Phys., 15, 1865–1899,Short summary
This work represents the first application of two-dimensional gas chromatography to broadly characterize the gas-phase emissions of biomass burning, including comparisons among the emissions from burns of selected conifer, grass, crop residue, and peat fuel types. In these smoke samples, over 700 compounds were detected, which are discussed in the context of potential secondary organic aerosol formation.
C. E. Stockwell, P. R. Veres, J. Williams, and R. J. Yokelson
Atmos. Chem. Phys., 15, 845–865,Short summary
We used a high-resolution proton-transfer-reaction time-of-flight mass spectrometer to measure emissions from peat, crop residue, cooking fires, etc. We assigned > 80% of the mass of gas-phase organic compounds and much of it was secondary organic aerosol precursors. The open cooking emissions were much larger than from advanced cookstoves. Little-studied N-containing organic compounds accounted for 0.1-8.7% of the fuel N and may influence new particle formation.
A. P. Sullivan, A. A. May, T. Lee, G. R. McMeeking, S. M. Kreidenweis, S. K. Akagi, R. J. Yokelson, S. P. Urbanski, and J. L. Collett Jr.
Atmos. Chem. Phys., 14, 10535–10545,
C. E. Stockwell, R. J. Yokelson, S. M. Kreidenweis, A. L. Robinson, P. J. DeMott, R. C. Sullivan, J. Reardon, K. C. Ryan, D. W. T. Griffith, and L. Stevens
Atmos. Chem. Phys., 14, 9727–9754,
W. C. Keene, J. L. Moody, J. N. Galloway, J. M. Prospero, O. R. Cooper, S. Eckhardt, and J. R. Maben
Atmos. Chem. Phys., 14, 8119–8135,
R. P. Aryal, K. J. Voss, P. A. Terman, W. C. Keene, J. L. Moody, E. J. Welton, and B. N. Holben
Atmos. Chem. Phys., 14, 7617–7629,
E. Saikawa, R. G. Prinn, E. Dlugokencky, K. Ishijima, G. S. Dutton, B. D. Hall, R. Langenfelds, Y. Tohjima, T. Machida, M. Manizza, M. Rigby, S. O'Doherty, P. K. Patra, C. M. Harth, R. F. Weiss, P. B. Krummel, M. van der Schoot, P. J. Fraser, L. P. Steele, S. Aoki, T. Nakazawa, and J. W. Elkins
Atmos. Chem. Phys., 14, 4617–4641,
M. S. Long, W. C. Keene, R. C. Easter, R. Sander, X. Liu, A. Kerkweg, and D. Erickson
Atmos. Chem. Phys., 14, 3397–3425,
J. L. Moody, W. C. Keene, O. R. Cooper, K. J. Voss, R. Aryal, S. Eckhardt, B. Holben, J. R. Maben, M. A. Izaguirre, and J. N. Galloway
Atmos. Chem. Phys., 14, 691–717,
S. K. Akagi, I. R. Burling, A. Mendoza, T. J. Johnson, M. Cameron, D. W. T. Griffith, C. Paton-Walsh, D. R. Weise, J. Reardon, and R. J. Yokelson
Atmos. Chem. Phys., 14, 199–215,
R. Sander, A. A. P. Pszenny, W. C. Keene, E. Crete, B. Deegan, M. S. Long, J. R. Maben, and A. H. Young
Earth Syst. Sci. Data, 5, 385–392,
R. J. Yokelson, M. O. Andreae, and S. K. Akagi
Atmos. Meas. Tech., 6, 2155–2158,
S. Kundu, T. A. Quraishi, G. Yu, C. Suarez, F. N. Keutsch, and E. A. Stone
Atmos. Chem. Phys., 13, 4865–4875,
M. S. Long, W. C. Keene, R. Easter, R. Sander, A. Kerkweg, D. Erickson, X. Liu, and S. Ghan
Geosci. Model Dev., 6, 255–262,
S. K. Akagi, R. J. Yokelson, I. R. Burling, S. Meinardi, I. Simpson, D. R. Blake, G. R. McMeeking, A. Sullivan, T. Lee, S. Kreidenweis, S. Urbanski, J. Reardon, D. W. T. Griffith, T. J. Johnson, and D. R. Weise
Atmos. Chem. Phys., 13, 1141–1165,
R. J. Yokelson, I. R. Burling, J. B. Gilman, C. Warneke, C. E. Stockwell, J. de Gouw, S. K. Akagi, S. P. Urbanski, P. Veres, J. M. Roberts, W. C. Kuster, J. Reardon, D. W. T. Griffith, T. J. Johnson, S. Hosseini, J. W. Miller, D. R. Cocker III, H. Jung, and D. R. Weise
Atmos. Chem. Phys., 13, 89–116,
Related subject area
Subject: Gases | Research Activity: Atmospheric Modelling | Altitude Range: Troposphere | Science Focus: Chemistry (chemical composition and reactions)Impact of international shipping emissions on ozone and PM2.5 in East Asia during summer: the important role of HONO and ClNO2Modelling the impacts of iodine chemistry on the northern Indian Ocean marine boundary layerTime-dependent 3D simulations of tropospheric ozone depletion events in the Arctic spring using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem)Assessing and improving cloud-height-based parameterisations of global lightning flash rate, and their impact on lightning-produced NOx and tropospheric composition in a chemistry–climate modelImpact of regional Northern Hemisphere mid-latitude anthropogenic sulfur dioxide emissions on local and remote tropospheric oxidantsImpact of organic molecular structure on the estimation of atmospherically relevant physicochemical parametersSpatial and temporal variability in the hydroxyl (OH) radical: understanding the role of large-scale climate features and their influence on OH through its dynamical and photochemical driversAnalysis of atmospheric ammonia over South and East Asia based on the MOZART-4 model and its comparison with satellite and surface observationsAir quality and health benefits from ultra-low emission control policy indicated by continuous emission monitoring: a case study in the Yangtze River Delta region, ChinaBackground conditions for an urban greenhouse gas network in the Washington, DC, and Baltimore metropolitan regionExplicit modeling of isoprene chemical processing in polluted air masses in suburban areas of the Yangtze River Delta region: radical cycling and formation of ozone and formaldehydeEvaluation of the LOTOS-EUROS NO2 simulations using ground-based measurements and S5P/TROPOMI observations over GreeceReactive organic carbon emissions from volatile chemical productsA three-dimensional-model inversion of methyl chloroform to constrain the atmospheric oxidative capacityTechnical note: On comparing greenhouse gas emission metricsLate-spring and summertime tropospheric ozone and NO2 in western Siberia and the Russian Arctic: regional model evaluation and sensitivities10-year satellite-constrained fluxes of ammonia improve performance of chemistry transport modelsRevealing the sulfur dioxide emission reductions in China by assimilating surface observations in WRF-ChemTropospheric ozone in CMIP6 simulationsIdentifying forecast uncertainties for biogenic gases in the Po Valley related to model configuration in EURAD-IM during PEGASOS 2012Impact of reduced anthropogenic emissions during COVID-19 on air quality in IndiaA comparison of long-term trends in observations and emission inventories of NOxAttribution of the accelerating increase in atmospheric methane during 2010–2018 by inverse analysis of GOSAT observationsGlobal impact of COVID-19 restrictions on the surface concentrations of nitrogen dioxide and ozoneThe impact of inhomogeneous emissions and topography on ozone photochemistry in the vicinity of Hong Kong IslandInverse modelling of carbonyl sulfide: implementation, evaluation and implications for the global budgetInfluence of aromatics on tropospheric gas-phase compositionEmission inventory of air pollutants and chemical speciation for specific anthropogenic sources based on local measurements in the Yangtze River Delta region, ChinaPhotochemical environment over Southeast Asia primed for hazardous ozone levels with influx of nitrogen oxides from seasonal biomass burningAtmospheric-methane source and sink sensitivity analysis using Gaussian process emulationCarbon and air pollutant emissions from China's cement industry 1990–2015: trends, evolution of technologies, and driversUnexpected enhancement of ozone exposure and health risks during National Day in ChinaAssessment of pre-industrial to present-day anthropogenic climate forcing in UKESM1Technical note: A high-resolution inverse modelling technique for estimating surface CO2 fluxes based on the NIES-TM–FLEXPART coupled transport model and its adjointImprovement of the satellite-derived NOx emissions on air quality modeling and its effect on ozone and secondary inorganic aerosol formation in the Yangtze River Delta, ChinaAircraft-based inversions quantify the importance of wetlands and livestock for Upper Midwest methane emissionsTime-resolved emission reductions for atmospheric chemistry modelling in Europe during the COVID-19 lockdownsRapid increase in summer surface ozone over the North China Plain during 2013–2019: a side effect of particulate matter reduction control?Estimation of fire-induced carbon emission from Equatorial Asia in 2015 by using in situ aircraft and ship observationsPan-Arctic surface ozone: modelling vs. measurementsInfluence of aerosol copper on HO2 uptake: a novel parameterized equationRole of ammonia in European air quality with changing land and ship emissions between 1990 and 2030Discrepancies between MICS-Asia III simulation and observation for surface ozone in the marine atmosphere over the northwestern Pacific Asian Rim regionCorrecting model biases of CO in East Asia: impact on oxidant distributions during KORUS-AQQuantifying the emission changes and associated air quality impacts during the COVID-19 pandemic on the North China Plain: a response modeling studyOrganic pollutants from tropical peatland fires: regional influences and its impact on lower stratospheric ozoneDo alternative inventories converge on the spatiotemporal representation of spring ammonia emissions in France?Large and increasing methane emissions from Eastern Amazonia derived from satellite data, 2010–2018Impacts of global NOx inversions on NO2 and ozone simulationsQuantifying sources of Brazil's CH4 emissions between 2010 and 2018 from satellite data
Jianing Dai and Tao Wang
Atmos. Chem. Phys., 21, 8747–8759,Short summary
We used the WRF–Chem model with the latest HONO and ClNO2 processes to investigate their effects on the concentrations of ROx radicals, O3, and PM2.5 in Asia during summer. The results show that the ship-derived HONO and ClNO2 increased the ROx radical concentration by 2–3 times and subsequently increased the O3 and PM2.5 concentrations in marine areas. These findings indicate the importance of these nitrogen processes in the evaluation of the impact of ship emissions on air quality.
Anoop S. Mahajan, Qinyi Li, Swaleha Inamdar, Kirpa Ram, Alba Badia, and Alfonso Saiz-Lopez
Atmos. Chem. Phys., 21, 8437–8454,Short summary
Using a regional model, we show that iodine-catalysed reactions cause large regional changes in the chemical composition in the northern Indian Ocean, with peak changes of up to 25 % in O3, 50 % in nitrogen oxides (NO and NO2), 15 % in hydroxyl radicals (OH), 25 % in hydroperoxyl radicals (HO2), and up to a 50 % change in the nitrate radical (NO3). These results show the importance of including iodine chemistry in modelling the atmosphere in this region.
Maximilian Herrmann, Holger Sihler, Udo Frieß, Thomas Wagner, Ulrich Platt, and Eva Gutheil
Atmos. Chem. Phys., 21, 7611–7638,Short summary
Time-dependent 3D numerical simulations of tropospheric bromine release and ozone depletion events (ODEs) in the Arctic polar spring of 2009 are compared to observations. Simulation results agree well with the observations at both Utqiaġvik, Alaska, and at Summit, Greenland. In a parameter study, different settings for the bromine release mechanism are evaluated. An enhancement of the bromine release mechanism improves the agreement regarding the occurrence of ODEs with the observations.
Ashok K. Luhar, Ian E. Galbally, Matthew T. Woodhouse, and Nathan Luke Abraham
Atmos. Chem. Phys., 21, 7053–7082,Short summary
Lightning-generated nitrogen oxides (LNOx) greatly influence tropospheric photochemistry. The most common parameterisation of lightning flash rate used to calculate LNOx in global composition models underestimates measurements over the ocean by a factor of 20–25. We formulate and validate an alternative parameterisation to remedy this problem. The new scheme causes an increase in the ozone burden by 8.5 % and the hydroxyl radical by 13 %, and these have implications for climate and air quality.
Daniel M. Westervelt, Arlene M. Fiore, Colleen B. Baublitz, and Gustavo Correa
Atmos. Chem. Phys., 21, 6799–6810,Short summary
Particulate air pollution in the atmosphere can impact the availability of gas-phase chemical constituents, which can then have feedbacks on gas-phase air pollutants. We use a chemistry–climate computer model to simulate the impact of particulate pollution from three major world regions on gas-phase chemical constituents. We find that surface-level ozone air pollution decreases by up to 5 ppbv over China in response to Chinese particulate air pollution, which has implications for policy.
Gabriel Isaacman-VanWertz and Bernard Aumont
Atmos. Chem. Phys., 21, 6541–6563,Short summary
There are tens of thousands of different chemical compounds in the atmosphere. To tackle this complexity, there are a wide range of different methods to estimate their physical and chemical properties. We use these methods to understand how much the detailed structure of a molecule impacts its properties, and the extent to which properties can be estimated without knowing this level of detail. We find that structure matters, but methods lacking that level of detail still perform reasonably well.
Daniel C. Anderson, Bryan N. Duncan, Arlene M. Fiore, Colleen B. Baublitz, Melanie B. Follette-Cook, Julie M. Nicely, and Glenn M. Wolfe
Atmos. Chem. Phys., 21, 6481–6508,Short summary
We demonstrate that large-scale climate features are the primary driver of year-to-year variability in simulated values of the hydroxyl radical, the primary atmospheric oxidant, over 1980–2018. The El Niño–Southern Oscillation is the dominant mode of hydroxyl variability, resulting in large-scale global decreases in OH during El Niño events. Other climate modes, such as the Australian monsoon and the North Atlantic Oscillation, have impacts of similar magnitude but on on more localized scales.
Pooja V. Pawar, Sachin D. Ghude, Chinmay Jena, Andrea Móring, Mark A. Sutton, Santosh Kulkarni, Deen Mani Lal, Divya Surendran, Martin Van Damme, Lieven Clarisse, Pierre-François Coheur, Xuejun Liu, Gaurav Govardhan, Wen Xu, Jize Jiang, and Tapan Kumar Adhya
Atmos. Chem. Phys., 21, 6389–6409,Short summary
In this study, simulations of atmospheric ammonia (NH3) with MOZART-4 and HTAP-v2 are compared with satellite (IASI) and ground-based measurements to understand the spatial and temporal variability of NH3 over two emission hotspot regions of Asia, the IGP and the NCP. Our simulations indicate that the formation of ammonium aerosols is quicker over the NCP than the IGP, leading to smaller NH3 columns over the higher NH3-emitting NCP compared to the IGP region for comparable emissions.
Yan Zhang, Yu Zhao, Meng Gao, Xin Bo, and Chris P. Nielsen
Atmos. Chem. Phys., 21, 6411–6430,Short summary
We combined air quality and exposure response models to analyze the benefits for air quality and human health of China’s ultra-low emission policy in one of its most developed regions. Atmospheric observations and the air quality model were also used to demonstrate improvement of emission inventories incorporating online emission monitoring data. With implementation of the policy in both power and industrial sectors, the attributable deaths due to PM2.5 exposure are estimated to decrease 5.5 %.
Anna Karion, Israel Lopez-Coto, Sharon M. Gourdji, Kimberly Mueller, Subhomoy Ghosh, William Callahan, Michael Stock, Elizabeth DiGangi, Steve Prinzivalli, and James Whetstone
Atmos. Chem. Phys., 21, 6257–6273,Short summary
Estimating city emissions based on atmospheric observations requires that the portion of observed greenhouse gases that originated in the city be separated from the portion that originated outside the city, also known as the background concentration. Here, we investigate different methods to determine background concentrations for the Washington, DC, and Baltimore, MD, region and evaluate how well those methods work and the uncertainties they involve.
Kun Zhang, Ling Huang, Qing Li, Juntao Huo, Yusen Duan, Yuhang Wang, Elly Yaluk, Yangjun Wang, Qingyan Fu, and Li Li
Atmos. Chem. Phys., 21, 5905–5917,Short summary
Recently, high O3 concentrations were frequently observed in rural areas of the Yangtze River Delta (YRD) region under stagnant conditions. Using an online measurement and observation-based model, we investigated the budget of ROx radicals and the influence of isoprene chemistry on O3 formation. Our results underline that isoprene chemistry in the rural atmosphere becomes important with the participation of anthropogenic NOx.
Ioanna Skoulidou, Maria-Elissavet Koukouli, Astrid Manders, Arjo Segers, Dimitris Karagkiozidis, Myrto Gratsea, Dimitris Balis, Alkiviadis Bais, Evangelos Gerasopoulos, Trisevgeni Stavrakou, Jos van Geffen, Henk Eskes, and Andreas Richter
Atmos. Chem. Phys., 21, 5269–5288,Short summary
The performance of LOTOS-EUROS v2.2.001 regional chemical transport model NO2 simulations is investigated over Greece from June to December 2018. Comparison with in situ NO2 measurements shows a spatial correlation coefficient of 0.86, while the model underestimates the concentrations mostly during daytime (12 to 15:00 local time). Further, the simulated tropospheric NO2 columns are evaluated against ground-based MAX-DOAS NO2 measurements and S5P/TROPOMI observations for July and December 2018.
Karl M. Seltzer, Elyse Pennington, Venkatesh Rao, Benjamin N. Murphy, Madeleine Strum, Kristin K. Isaacs, and Havala O. T. Pye
Atmos. Chem. Phys., 21, 5079–5100,Short summary
Volatile chemical products (VCPs) are an increasingly important source of anthropogenic reactive organic carbon emissions. Here, we develop VCPy, a new framework to model organic emissions from VCPs throughout the United States. At the national-level, VCPy emissions are broadly consistent with the US EPA’s 2017 National Emission Inventory, however county-level and categorical estimates can differ substantially. An observational evaluation indicates high fidelity in the methods employed here.
Stijn Naus, Stephen A. Montzka, Prabir K. Patra, and Maarten C. Krol
Atmos. Chem. Phys., 21, 4809–4824,Short summary
Following up on previous box model studies, we employ a 3D transport model to estimate variations in the hydroxyl radical (OH) from observations of methyl chloroform (MCF). We derive small interannual OH variations that are consistent with variations in the El Niño–Southern Oscillation. We also find evidence for the release of MCF from oceans in atmospheric gradients of MCF. Both findings highlight the added value of a 3D transport model since box model studies did not identify these effects.
Ian Enting and Nathan Clisby
Atmos. Chem. Phys., 21, 4699–4708,Short summary
We provide a new framework for comparing short-lived greenhouse gases to long-lived greenhouse gases such as carbon dioxide using methane as an example. This can clarify the differences between various proposals that have been introduced in order to overcome the use of global warming potentials as a measure of greenhouse gas equivalence.
Thomas Thorp, Stephen R. Arnold, Richard J. Pope, Dominick V. Spracklen, Luke Conibear, Christoph Knote, Mikhail Arshinov, Boris Belan, Eija Asmi, Tuomas Laurila, Andrei I. Skorokhod, Tuomo Nieminen, and Tuukka Petäjä
Atmos. Chem. Phys., 21, 4677–4697,Short summary
We compare modelled near-surface pollutants with surface and satellite observations to better understand the controls on the regional concentrations of pollution in western Siberia for late spring and summer in 2011. We find two commonly used emission inventories underestimate human emissions when compared to observations. Transport emissions are the main source of pollutants within the region during this period, whilst fire emissions peak during June and are only significant south of 60° N.
Nikolaos Evangeliou, Yves Balkanski, Sabine Eckhardt, Anne Cozic, Martin Van Damme, Pierre-François Coheur, Lieven Clarisse, Mark W. Shephard, Karen E. Cady-Pereira, and Didier Hauglustaine
Atmos. Chem. Phys., 21, 4431–4451,Short summary
Ammonia, a substance that has played a key role in sustaining life, has been increasing in the atmosphere, affecting climate and humans. Understanding the reasons for this increase is important for the beneficial use of ammonia. The evolution of satellite products gives us the opportunity to calculate ammonia emissions easier. We calculated global ammonia emissions over the last 10 years, incorporated them into a chemistry model and recorded notable improvement in reproducing observations.
Tie Dai, Yueming Cheng, Daisuke Goto, Yingruo Li, Xiao Tang, Guangyu Shi, and Teruyuki Nakajima
Atmos. Chem. Phys., 21, 4357–4379,Short summary
The anthropogenic emission of sulfur dioxide (SO2) over China has significantly declined as a consequence of the clean air actions. We have developed a new emission inversion system to dynamically update the SO2 emission grid by grid over China by assimilating ground-based SO2 observations. The inverted SO2 emission over China in November 2016 on average had declined by 49.4 % since 2010, which is well in agreement with the bottom-up estimation of 48.0 %.
Paul T. Griffiths, Lee T. Murray, Guang Zeng, Youngsub Matthew Shin, N. Luke Abraham, Alexander T. Archibald, Makoto Deushi, Louisa K. Emmons, Ian E. Galbally, Birgit Hassler, Larry W. Horowitz, James Keeble, Jane Liu, Omid Moeini, Vaishali Naik, Fiona M. O'Connor, Naga Oshima, David Tarasick, Simone Tilmes, Steven T. Turnock, Oliver Wild, Paul J. Young, and Prodromos Zanis
Atmos. Chem. Phys., 21, 4187–4218,Short summary
We analyse the CMIP6 Historical and future simulations for tropospheric ozone, a species which is important for many aspects of atmospheric chemistry. We show that the current generation of models agrees well with observations, being particularly successful in capturing trends in surface ozone and its vertical distribution in the troposphere. We analyse the factors that control ozone and show that they evolve over the period of the CMIP6 experiments.
Annika Vogel and Hendrik Elbern
Atmos. Chem. Phys., 21, 4039–4057,Short summary
Forecasts of biogenic trace gases highly depend on the model setup and input fields. This study identifies sources of related forecast uncertainties for biogenic gases. Exceptionally high differences in both biogenic emissions and pollutant transport in the Po Valley are identified to be caused by the representation of the land surface and boundary layer dynamics. Consequently, changes in the model configuration are shown to induce significantly different local concentrations of biogenic gases.
Mengyuan Zhang, Arpit Katiyar, Shengqiang Zhu, Juanyong Shen, Men Xia, Jinlong Ma, Sri Harsha Kota, Peng Wang, and Hongliang Zhang
Atmos. Chem. Phys., 21, 4025–4037,Short summary
We studied changes in air quality in India induced by the COVID-19 lockdown through both surface observations and the CMAQ model. Our results show that emission reductions improved the air quality across India during the lockdown. On average, the levels of PM2.5 and O3 decreased by 28 % and 15 %, indicating positive effects of lockdown measures. We suggest that more stringent and localized emission control strategies should be implemented in India to mitigate air pollutions.
Elena Macdonald, Noelia Otero, and Tim Butler
Atmos. Chem. Phys., 21, 4007–4023,Short summary
NO2 limit values are still regularly exceeded in many European cities despite decreasing emissions. Measurements of NOx concentrations from stations across Europe were systematically analysed to assess long-term changes observed in urban areas. We compared trends in concentration increments to trends in total and traffic emissions to find potential discrepancies. The results can help in evaluating inaccuracies in emission inventories and in improving spatial imbalances in data availability.
Yuzhong Zhang, Daniel J. Jacob, Xiao Lu, Joannes D. Maasakkers, Tia R. Scarpelli, Jian-Xiong Sheng, Lu Shen, Zhen Qu, Melissa P. Sulprizio, Jinfeng Chang, A. Anthony Bloom, Shuang Ma, John Worden, Robert J. Parker, and Hartmut Boesch
Atmos. Chem. Phys., 21, 3643–3666,Short summary
We use 2010–2018 satellite observations of atmospheric methane to interpret the factors controlling atmospheric methane and its accelerating increase during the period. The 2010–2018 increase in global methane emissions is driven by tropical and boreal wetlands and tropical livestock (South Asia, Africa, Brazil), with an insignificant positive trend in emissions from the fossil fuel sector. The peak methane growth rates in 2014–2015 are also contributed by low OH and high fire emissions.
Christoph A. Keller, Mathew J. Evans, K. Emma Knowland, Christa A. Hasenkopf, Sruti Modekurty, Robert A. Lucchesi, Tomohiro Oda, Bruno B. Franca, Felipe C. Mandarino, M. Valeria Díaz Suárez, Robert G. Ryan, Luke H. Fakes, and Steven Pawson
Atmos. Chem. Phys., 21, 3555–3592,Short summary
This study combines surface observations and model simulations to quantify the impact of COVID-19 restrictions on air quality across the world. The presented methodology removes the confounding impacts of meteorology on air pollution. Our results indicate that surface concentrations of nitrogen dioxide, an important air pollutant emitted during the combustion of fossil fuels, declined by up to 60 % following the implementation of COVID-19 containment measures.
Yuting Wang, Yong-Feng Ma, Domingo Muñoz-Esparza, Cathy W. Y. Li, Mary Barth, Tao Wang, and Guy P. Brasseur
Atmos. Chem. Phys., 21, 3531–3553,Short summary
Large-eddy simulations (LESs) were performed in the mountainous region of the island of Hong Kong to investigate the degree to which the rates of chemical reactions between two reactive species are reduced due to the segregation of species within the convective boundary layer. We show that the inhomogeneity in emissions plays an important role in the segregation effect. Topography also has a significant influence on the segregation locally.
Jin Ma, Linda M. J. Kooijmans, Ara Cho, Stephen A. Montzka, Norbert Glatthor, John R. Worden, Le Kuai, Elliot L. Atlas, and Maarten C. Krol
Atmos. Chem. Phys., 21, 3507–3529,Short summary
Carbonyl sulfide is an important trace gas in the atmosphere and useful to estimating gross primary productivity in ecosystems, but its sources and sinks remain highly uncertain. Therefore, we applied inverse model system TM5-4DVAR to better constrain the global budget. Our finding is in line with earlier studies, pointing to missing sources in the tropics and more uptake in high latitudes. We also stress the necessity of more ground-based observations and satellite data assimilation in future.
Domenico Taraborrelli, David Cabrera-Perez, Sara Bacer, Sergey Gromov, Jos Lelieveld, Rolf Sander, and Andrea Pozzer
Atmos. Chem. Phys., 21, 2615–2636,Short summary
Atmospheric pollutants from anthropogenic activities and biomass burning are usually regarded as ozone precursors. Monocyclic aromatics are no exception. Calculations with a comprehensive atmospheric model are consistent with this view but only for air masses close to pollution source regions. However, the same model predicts that aromatics, when transported to remote areas, may effectively destroy ozone. This loss of tropospheric ozone rivals the one attributed to bromine.
Jingyu An, Yiwei Huang, Cheng Huang, Xin Wang, Rusha Yan, Qian Wang, Hongli Wang, Sheng'ao Jing, Yan Zhang, Yiming Liu, Yuan Chen, Chang Xu, Liping Qiao, Min Zhou, Shuhui Zhu, Qingyao Hu, Jun Lu, and Changhong Chen
Atmos. Chem. Phys., 21, 2003–2025,Short summary
This study established a 4 km × 4 km anthropogenic emission inventory in the Yangtze River Delta region, China, for 2017 based on locally measured emission factors and source profiles. There are high-intensity NOx and NMVOC species emissions in the eastern areas of the region. Toluene, 1,2,4-trimethylbenzene, m,p-xylene, propylene, ethylene, o-xylene, and OVOCs from industry and mobile sources have the highest comprehensive potentials for ozone and secondary organic aerosol formation.
Margaret R. Marvin, Paul I. Palmer, Barry G. Latter, Richard Siddans, Brian J. Kerridge, Mohd Talib Latif, and Md Firoz Khan
Atmos. Chem. Phys., 21, 1917–1935,Short summary
We use an atmospheric chemistry model in combination with satellite and surface observations to investigate how biomass burning affects tropospheric ozone over Southeast Asia during its fire seasons. We find that nitrogen oxides from biomass burning were responsible for about 30 % of the regional ozone formation potential, and we estimate that ozone from biomass burning caused more than 400 excess premature deaths in Southeast Asia during the peak burning months of March and September 2014.
Angharad C. Stell, Luke M. Western, Tomás Sherwen, and Matthew Rigby
Atmos. Chem. Phys., 21, 1717–1736,Short summary
Although it is the second-most important greenhouse gas, our understanding of the atmospheric-methane budget is limited. The uncertainty highlights the need for new tools to investigate sources and sinks. Here, we use a Gaussian process emulator to efficiently approximate the response of atmospheric-methane observations to changes in the most uncertain emission or loss processes. With this new method, we rigorously quantify the sensitivity of atmospheric observations to budget uncertainties.
Jun Liu, Dan Tong, Yixuan Zheng, Jing Cheng, Xinying Qin, Qinren Shi, Liu Yan, Yu Lei, and Qiang Zhang
Atmos. Chem. Phys., 21, 1627–1647,Short summary
In this study, we investigated the decadal changes in carbon dioxide and air pollutant emissions in China's cement industry for the period 1990–2015 based on intensive unit-based information. We found that from 1990 to 2015, accompanied by a 10.3-fold increase in cement production, CO2, SO2, and NOx emissions from China's cement industry increased by 627 %, 56 %, and 659 %, whereas CO, PM2.5, and PM10 emissions decreased by 9 %, 63 %, and 59 %, respectively.
Peng Wang, Juanyong Shen, Men Xia, Shida Sun, Yanli Zhang, Hongliang Zhang, and Xinming Wang
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
Ozone (O3) pollution has received extensive attention due to the worsening air quality and rising health risks. The Chinese National Day Holidays (CNDH) is associated with intensive commercial and tourist activities, serves as a valuable experiment to evaluate O3 response during the holiday. We find sharply increasing trends of observed O3 concentrations throughout China during the CNDH, leading to 33 % additional total daily deaths.
Fiona M. O'Connor, N. Luke Abraham, Mohit Dalvi, Gerd A. Folberth, Paul T. Griffiths, Catherine Hardacre, Ben T. Johnson, Ron Kahana, James Keeble, Byeonghyeon Kim, Olaf Morgenstern, Jane P. Mulcahy, Mark Richardson, Eddy Robertson, Jeongbyn Seo, Sungbo Shim, João C. Teixeira, Steven T. Turnock, Jonny Williams, Andrew J. Wiltshire, Stephanie Woodward, and Guang Zeng
Atmos. Chem. Phys., 21, 1211–1243,Short summary
This paper calculates how changes in emissions and/or concentrations of different atmospheric constituents since the pre-industrial era have altered the Earth's energy budget at the present day using a metric called effective radiative forcing. The impact of land use change is also assessed. We find that individual contributions do not add linearly, and different Earth system interactions can affect the magnitude of the calculated effective radiative forcing.
Shamil Maksyutov, Tomohiro Oda, Makoto Saito, Rajesh Janardanan, Dmitry Belikov, Johannes W. Kaiser, Ruslan Zhuravlev, Alexander Ganshin, Vinu K. Valsala, Arlyn Andrews, Lukasz Chmura, Edward Dlugokencky, László Haszpra, Ray L. Langenfelds, Toshinobu Machida, Takakiyo Nakazawa, Michel Ramonet, Colm Sweeney, and Douglas Worthy
Atmos. Chem. Phys., 21, 1245–1266,Short summary
In order to improve the top-down estimation of the anthropogenic greenhouse gas emissions, a high-resolution inverse modelling technique was developed for applications to global transport modelling of carbon dioxide and other greenhouse gases. A coupled Eulerian–Lagrangian transport model and its adjoint are combined with surface fluxes at 0.1° resolution to provide high-resolution forward simulation and inverse modelling of surface fluxes accounting for signals from emission hot spots.
Yang Yang, Yu Zhao, Lei Zhang, Jie Zhang, Xin Huang, Xuefen Zhao, Yan Zhang, Mengxiao Xi, and Yi Lu
Atmos. Chem. Phys., 21, 1191–1209,Short summary
We conducted new NOx emission estimation based on the satellite-derived NO2 column constraint and found reduced emissions compared to previous estimates for a developed region in east China. The subsequent improvement in air quality modeling was demonstrated based on available ground observations. With multiple emission reduction cases for various pollutants, we explored the effective control approaches for ozone and inorganic aerosol pollution.
Xueying Yu, Dylan B. Millet, Kelley C. Wells, Daven K. Henze, Hansen Cao, Timothy J. Griffis, Eric A. Kort, Genevieve Plant, Malte J. Deventer, Randall K. Kolka, D. Tyler Roman, Kenneth J. Davis, Ankur R. Desai, Bianca C. Baier, Kathryn McKain, Alan C. Czarnetzki, and A. Anthony Bloom
Atmos. Chem. Phys., 21, 951–971,Short summary
Methane concentrations have doubled since 1750. The US Upper Midwest is a key region contributing to such trends, but sources are poorly understood. We collected and analyzed aircraft data to resolve spatial and timing biases in wetland and livestock emission estimates and uncover errors in inventory treatment of manure management. We highlight the importance of intensive agriculture for the regional and US methane budgets and the potential for methane mitigation through improved management.
Marc Guevara, Oriol Jorba, Albert Soret, Hervé Petetin, Dene Bowdalo, Kim Serradell, Carles Tena, Hugo Denier van der Gon, Jeroen Kuenen, Vincent-Henri Peuch, and Carlos Pérez García-Pando
Atmos. Chem. Phys., 21, 773–797,Short summary
Most European countries have imposed lockdowns to combat the spread of the COVID-19 pandemic. Such a socioeconomic disruption has resulted in a sudden drop of atmospheric emissions and air pollution levels. This study quantifies the daily reductions in national emissions and associated levels of nitrogen dioxide (NO2) due to the COVID-19 lockdowns in Europe, by making use of multiple open-access measured activity data as well as artificial intelligence and modelling techniques.
Xiaodan Ma, Jianping Huang, Tianliang Zhao, Cheng Liu, Kaihui Zhao, Jia Xing, and Wei Xiao
Atmos. Chem. Phys., 21, 1–16,Short summary
The present work aims at identifying and quantifying the relative contributions of the key factors in driving a rapid increase in summertime surface O3 over the North China Plain during 2013–2019. In addition to anthropogenic emission reduction and meteorological variabilities, our study highlights the importance of inclusion of aerosol absorption and scattering properties rather than aerosol abundance only in accurate assessment of aerosol radiative effect on surface O3 formation and change.
Yosuke Niwa, Yousuke Sawa, Hideki Nara, Toshinobu Machida, Hidekazu Matsueda, Taku Umezawa, Akihiko Ito, Shin-Ichiro Nakaoka, Hiroshi Tanimoto, and Yasunori Tohjima
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
Fires in Equatorial Asia release a large amount of carbon into the atmosphere. Extensively using high-precision atmospheric data of carbon dioxide (CO2) from a commercial aircraft observation project, we estimated the fire carbon emission in Equatorial Asia induced by the big El Niño in 2015. Additional shipboard measurement data elucidated the validity of the analysis and the best estimate indicated 273 Tg C for fire emission during September–October 2015.
Xin Yang, Anne-M. Blechschmidt, Kristof Bognar, Audra McClure-Begley, Sara Morris, Irina Petropavlovskikh, Andreas Richter, Henrik Skov, Kimberly Strong, David W. Tarasick, Taneil Uttal, Mika Vestenius, and Xiaoyi Zhao
Atmos. Chem. Phys., 20, 15937–15967,Short summary
This is a modelling-based study on Arctic surface ozone, with a particular focus on spring ozone depletion events (i.e. with concentrations < 10 ppbv). Model experiments show that model runs with blowing-snow-sourced sea salt aerosols implemented as a source of reactive bromine can reproduce well large-scale ozone depletion events observed in the Arctic. This study supplies modelling evidence of the proposed mechanism of reactive-bromine release from blowing snow on sea ice (Yang et al., 2008).
Huan Song, Xiaorui Chen, Keding Lu, Qi Zou, Zhaofeng Tan, Hendrik Fuchs, Alfred Wiedensohler, Daniel R. Moon, Dwayne E. Heard, María-Teresa Baeza-Romero, Mei Zheng, Andreas Wahner, Astrid Kiendler-Scharr, and Yuanhang Zhang
Atmos. Chem. Phys., 20, 15835–15850,Short summary
Accurate calculation of the HO2 uptake coefficient is one of the key parameters to quantify the co-reduction of both aerosol and ozone pollution. We modelled various lab measurements of γHO2 based on a gas-liquid phase kinetic model and developed a state-of-the-art parameterized equation. Based on a dataset from a comprehensive field campaign in the North China Plain, we proposed that the determination of the heterogeneous uptake process for HO2 should be included in future field campaigns.
Sebnem Aksoyoglu, Jianhui Jiang, Giancarlo Ciarelli, Urs Baltensperger, and André S. H. Prévôt
Atmos. Chem. Phys., 20, 15665–15680,Short summary
We investigated the role of ammonia in European air quality between 1990 and 2030 under varying land and ship emissions. If ship emissions will be regulated more strictly in the future, particulate nitrate will decrease in coastal areas in northern Europe, while sulfate aerosol will decrease in the Mediterranean region. We predict a shift in the sensitivity of aerosol formation from NH3 towards NOx emissions between 1990 and 2030 in most of Europe except the eastern part of the model domain.
Hajime Akimoto, Tatsuya Nagashima, Natsumi Kawano, Li Jie, Joshua S. Fu, and Zifa Wang
Atmos. Chem. Phys., 20, 15003–15014,Short summary
In order to perform proper model simulation of ozone near the ground in the coastal area of northeastern Asia, it has been found that it is very important to select appropriate dry deposition velocities of ozone on the oceanic water of specific area of the northwestern Pacific. Empirical measurement of the mixing ratios and dry deposition flux of ozone over the ocean in this area is highly recommended.
Benjamin Gaubert, Louisa K. Emmons, Kevin Raeder, Simone Tilmes, Kazuyuki Miyazaki, Avelino F. Arellano Jr., Nellie Elguindi, Claire Granier, Wenfu Tang, Jérôme Barré, Helen M. Worden, Rebecca R. Buchholz, David P. Edwards, Philipp Franke, Jeffrey L. Anderson, Marielle Saunois, Jason Schroeder, Jung-Hun Woo, Isobel J. Simpson, Donald R. Blake, Simone Meinardi, Paul O. Wennberg, John Crounse, Alex Teng, Michelle Kim, Russell R. Dickerson, Hao He, Xinrong Ren, Sally E. Pusede, and Glenn S. Diskin
Atmos. Chem. Phys., 20, 14617–14647,Short summary
This study investigates carbon monoxide pollution in East Asia during spring using a numerical model, satellite remote sensing, and aircraft measurements. We found an underestimation of emission sources. Correcting the emission bias can improve air quality forecasting of carbon monoxide and other species including ozone. Results also suggest that controlling VOC and CO emissions, in addition to widespread NOx controls, can improve ozone pollution over East Asia.
Jia Xing, Siwei Li, Yueqi Jiang, Shuxiao Wang, Dian Ding, Zhaoxin Dong, Yun Zhu, and Jiming Hao
Atmos. Chem. Phys., 20, 14347–14359,Short summary
Quantifying emission changes is a prerequisite for assessment of control effectiveness in improving air quality. However, traditional bottom-up methods usually take months to perform and limit timely assessments. A novel method was developed by using a response model that provides real-time estimation of emission changes based on air quality observations. It was successfully applied to quantify emission changes on the North China Plain due to the COVID-19 pandemic shutdown.
Simon Rosanka, Bruno Franco, Lieven Clarisse, Pierre-François Coheur, Andreas Wahner, and Domenico Taraborrelli
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
The strong El Niño in 2015 led to a particular dry season in Indonesia and favoured severe peatland fires. The smouldering conditions of these fires and the high carbon content of peat resulted in high volatile organic compound (VOC) emissions. By using a comprehensive atmospheric model, we show that these emissions have a significant impact on the tropospheric composition and oxidation capacity. These emissions are transported into to the lower stratosphere, resulting in a depletion of ozone.
Audrey Fortems-Cheiney, Gaëlle Dufour, Karine Dufossé, Florian Couvidat, Jean-Marc Gilliot, Guillaume Siour, Matthias Beekmann, Gilles Foret, Frederik Meleux, Lieven Clarisse, Pierre-François Coheur, Martin Van Damme, Cathy Clerbaux, and Sophie Génermont
Atmos. Chem. Phys., 20, 13481–13495,Short summary
Studies have suggested the importance of ammonia emissions on pollution particle formation over Europe, whose main atmospheric source is agriculture. In this study, we performed an inter-comparison of two alternative inventories, both with a reference inventory, that quantify the French ammonia emissions during spring 2011. Over regions with large mineral fertilizer use, like over northeastern France, NH3 emissions are probably considerably underestimated by the reference inventory.
Chris Wilson, Martyn P. Chipperfield, Manuel Gloor, Robert J. Parker, Hartmut Boesch, Joey McNorton, Luciana V. Gatti, John B. Miller, Luana S. Basso, and Sarah A. Monks
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
Methane (CH4) is an important greenhouse gas emitted from wetlands like those found in the basin of the Amazon River. Using an atmospheric model and observations from the GOSAT satellite, we quantified CH4 emissions from Amazonia during the previous decade. We found that the largest emissions came from a region in the eastern Basin, and that emissions there were rising faster than in other areas of South America. This finding was supported by CH4 observations made on aircraft within the Basin.
Zhen Qu, Daven K. Henze, Owen R. Cooper, and Jessica L. Neu
Atmos. Chem. Phys., 20, 13109–13130,Short summary
We use satellite observations and chemical transport modeling to quantify sources of NOx, a major air pollutant, over the past decade. We find improved simulations of the magnitude, seasonality, and trends of NO2 and ozone concentrations using these derived emissions. Changes in ozone pollution driven by human and natural sources are identified in different regions. This work shows the benefits of remote-sensing data and inverse modeling for more accurate ozone simulations.
Rachel L. Tunnicliffe, Anita L. Ganesan, Robert J. Parker, Hartmut Boesch, Nicola Gedney, Benjamin Poulter, Zhen Zhang, Jošt V. Lavrič, David Walter, Matthew Rigby, Stephan Henne, Dickon Young, and Simon O'Doherty
Atmos. Chem. Phys., 20, 13041–13067,Short summary
This study quantifies Brazil’s emissions of a potent atmospheric greenhouse gas, methane. This is in the field of atmospheric modelling and uses remotely sensed data and surface measurements of methane concentrations as well as an atmospheric transport model to interpret the data. Because of Brazil’s large emissions from wetlands, agriculture and biomass burning, these emissions affect global methane concentrations and thus are of global significance.
Angel, H. and Alisa, Z.: Environmental Performance Index, 1–5, American Cancer Society, https://doi.org/10.1002/9781118445112.stat03789.pub2, 2016. a
Emmons, L. K., Walters, S., Hess, P. G., Lamarque, J.-F., Pfister, G. G., Fillmore, D., Granier, C., Guenther, A., Kinnison, D., Laepple, T., Orlando, J., Tie, X., Tyndall, G., Wiedinmyer, C., Baughcum, S. L., and Kloster, S.: Description and evaluation of the Model for Ozone and Related chemical Tracers, version 4 (MOZART-4), Geosci. Model Dev., 3, 43–67, https://doi.org/10.5194/gmd-3-43-2010, 2010. a
Guenther, A. B., Jiang, X., Heald, C. L., Sakulyanontvittaya, T., Duhl, T., Emmons, L. K., and Wang, X.: The Model of Emissions of Gases and Aerosols from Nature version 2.1 (MEGAN2.1): an extended and updated framework for modeling biogenic emissions, Geosci. Model Dev., 5, 1471–1492, https://doi.org/10.5194/gmd-5-1471-2012, 2012. a
Janssens-Maenhout, G., Pagliari, V., and Muntean, M.: Global emission inventories in the Emission Database for Global Atmospheric Research (EDGAR) – Manual (I): Gridding: EDGAR emissions distribution on global grid maps, Tech. Rep. 25785, JRC, 2013. a
Janssens-Maenhout, G., Crippa, M., Guizzardi, D., Dentener, F., Muntean, M., Pouliot, G., Keating, T., Zhang, Q., Kurokawa, J., Wankmüller, R., Denier van der Gon, H., Kuenen, J. J. P., Klimont, Z., Frost, G., Darras, S., Koffi, B., and Li, M.: HTAP_v2.2: a mosaic of regional and global emission grid maps for 2008 and 2010 to study hemispheric transport of air pollution, Atmos. Chem. Phys., 15, 11411–11432, https://doi.org/10.5194/acp-15-11411-2015, 2015. a, b
Jayarathne, T., Stockwell, C. E., Bhave, P. V., Praveen, P. S., Rathnayake, C. M., Islam, Md. R., Panday, A. K., Adhikari, S., Maharjan, R., Goetz, J. D., DeCarlo, P. F., Saikawa, E., Yokelson, R. J., and Stone, E. A.: Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE): emissions of particulate matter from wood- and dung-fueled cooking fires, garbage and crop residue burning, brick kilns, and other sources, Atmos. Chem. Phys., 18, 2259–2286, https://doi.org/10.5194/acp-18-2259-2018, 2018. a, b, c
Jimenez, P. A. and J. Dudhia: Improving the representation of resolved and unresolved topographic effects on surface wind in the WRF model, J. Appl. Meteorol. Climatol., 51, 300–316, 2012.
Kim, B. M., Park, J.-S., Kim, S.-W., Kim, H., Jeon, H., Cho, C., Kim, J.-H., Hong, S., Rupakheti, M., Panday, A. K., Park, R. J., Hong, J., and Yoon, S.-C.: Source apportionment of PM10 mass and particulate carbon in the Kathmandu Valley, Nepal, Atmos. Environ., 123, 190–199, https://doi.org/10.1016/j.atmosenv.2015.10.082, 2015. a, b
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Air pollution is one of the most pressing environmental issues in the Kathmandu Valley, the capital city of Nepal. We estimated emissions from two of the major source types in the valley (vehicles and brick kilns) and found that they have significant impacts on air quality surrounding the valley. Our results highlight the importance of improving local emissions estimates for air quality modeling.
Air pollution is one of the most pressing environmental issues in the Kathmandu Valley, the...