Articles | Volume 11, issue 22
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Novel application of satellite and in-situ measurements to map surface-level NO2 in the Great Lakes region
C. J. Lee
Southern Ontario Centre for Atmospheric Aerosol Research, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
J. R. Brook
Air Quality Research Division, Science and Technology Branch, Environment Canada, Downsview, ON, Canada
G. J. Evans
Southern Ontario Centre for Atmospheric Aerosol Research, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
R. V. Martin
Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada
Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA
Air Quality Research Division, Science and Technology Branch, Environment Canada, Downsview, ON, Canada
Related subject area
Subject: Gases | Research Activity: Remote Sensing | Altitude Range: Troposphere | Science Focus: Physics (physical properties and processes)Ground-level gaseous pollutants (NO2, SO2, and CO) in China: daily seamless mapping and spatiotemporal variationsNH3 spatiotemporal variability over Paris, Mexico City, and Toronto, and its link to PM2.5 during pollution eventsMulti-axis differential optical absorption spectroscopy (MAX-DOAS) observations of formaldehyde and nitrogen dioxide at three sites in Asia and comparison with the global chemistry transport model CHASERQuantifying CH4 emissions in hard coal mines from TROPOMI and IASI observations using the wind-assigned anomaly methodEstimation of surface ammonia concentrations and emissions in China from the polar-orbiting Infrared Atmospheric Sounding Interferometer and the FY-4A Geostationary Interferometric Infrared SounderInterannual variability in the Australian carbon cycle over 2015–2019, based on assimilation of Orbiting Carbon Observatory-2 (OCO-2) satellite dataSource and variability of formaldehyde (HCHO) at northern high latitudes: an integrated satellite, aircraft, and model studyVolcanic SO2 layer height by TROPOMI/S5P: evaluation against IASI/MetOp and CALIOP/CALIPSO observationsSpaceborne tropospheric nitrogen dioxide (NO2) observations from 2005–2020 over the Yangtze River Delta (YRD), China: variabilities, implications, and driversNovel assessment of numerical forecasting model relative humidity with satellite probabilistic estimatesInfluence of springtime atmospheric circulation types on the distribution of air pollutants in the ArcticTechnical note: Evaluation of profile retrievals of aerosols and trace gases for MAX-DOAS measurements under different aerosol scenarios based on radiative transfer simulationsDiurnal evolution of total column and surface atmospheric ammonia in the megacity of Paris, France, during an intense springtime pollution episodeThe reduction in C2H6 from 2015 to 2020 over Hefei, eastern China, points to air quality improvement in ChinaMapping the drivers of formaldehyde (HCHO) variability from 2015 to 2019 over eastern China: insights from Fourier transform infrared observation and GEOS-Chem model simulationThe impact of Los Angeles Basin pollution and stratospheric intrusions on the surrounding San Gabriel Mountains as seen by surface measurements, lidar, and numerical modelsSudden changes in nitrogen dioxide emissions over Greece due to lockdown after the outbreak of COVID-19Monitoring CO emissions of the metropolis Mexico City using TROPOMI CO observationsPollution trace gas distributions and their transport in the Asian monsoon upper troposphere and lowermost stratosphere during the StratoClim campaign 2017Spatial distribution of enhanced BrO and its relation to meteorological parameters in Arctic and Antarctic sea ice regionsTrends of atmospheric water vapour in Switzerland from ground-based radiometry, FTIR and GNSS dataA Raman lidar tropospheric water vapour climatology and height-resolved trend analysis over Payerne, SwitzerlandThe potential of Orbiting Carbon Observatory-2 data to reduce the uncertainties in CO2 surface fluxes over Australia using a variational assimilation schemeObserving carbon dioxide emissions over China's cities and industrial areas with the Orbiting Carbon Observatory-2Observational evidence of moistening the lowermost stratosphere via isentropic mixing across the subtropical jetFourier transform infrared time series of tropospheric HCN in eastern China: seasonality, interannual variability, and source attributionNH3 emissions from large point sources derived from CrIS and IASI satellite observationsDiurnal cycle of short-term fluctuations of integrated water vapour above SwitzerlandRetrieval of total column and surface NO2 from Pandora zenith-sky measurementsMAX-DOAS measurements of tropospheric NO2 and HCHO in Nanjing and a comparison to ozone monitoring instrument observationsConsistency and representativeness of integrated water vapour from ground-based GPS observations and ERA-Interim reanalysisTowards monitoring localized CO2 emissions from space: co-located regional CO2 and NO2 enhancements observed by the OCO-2 and S5P satellitesVariability of bulk water vapor content in the marine cloudy boundary layers from microwave and near-infrared imageryTrends and trend reversal detection in 2 decades of tropospheric NO2 satellite observationsSatellite-derived sulfur dioxide (SO2) emissions from the 2014–2015 Holuhraun eruption (Iceland)Emissions of methane in Europe inferred by total column measurementsOn the interpretation of upper-tropospheric humidity based on a second-order retrieval from infrared radiancesCarbon monoxide air pollution on sub-city scales and along arterial roads detected by the Tropospheric Monitoring InstrumentGround-based MAX-DOAS observations of tropospheric formaldehyde VCDs and comparisons with the CAMS model at a rural site near Beijing during APEC 2014Trends in global tropospheric ozone inferred from a composite record of TOMS/OMI/MLS/OMPS satellite measurements and the MERRA-2 GMI simulationSpatial and temporal changes in SO2 regimes over China in the recent decade and the driving mechanismGlobal IWV trends and variability in atmospheric reanalyses and GPS observationsOzone seasonal evolution and photochemical production regime in the polluted troposphere in eastern China derived from high-resolution Fourier transform spectrometry (FTS) observationsAtmospheric CO and CH4 time series and seasonal variations on Reunion Island from ground-based in situ and FTIR (NDACC and TCCON) measurementsHarmonisation and trends of 20-year tropical tropospheric ozone dataCharacterizing biospheric carbon balance using CO2 observations from the OCO-2 satelliteDetection of O4 absorption around 328 and 419 nm in measured atmospheric absorption spectraInvestigations of temporal and spatial distribution of precursors SO2 and NO2 vertical columns in the North China Plain using mobile DOASQuantification of CO emissions from the city of Madrid using MOPITT satellite retrievals and WRF simulationsContributions of the troposphere and stratosphere to CH4 model biases
Jing Wei, Zhanqing Li, Jun Wang, Can Li, Pawan Gupta, and Maureen Cribb
Atmos. Chem. Phys., 23, 1511–1532,Short summary
This study estimated the daily seamless 10 km ambient gaseous pollutants (NO2, SO2, and CO) across China using machine learning with extensive input variables measured on monitors, satellites, and models. Our dataset yields a high data quality via cross-validation at varying spatiotemporal scales and outperforms most previous related studies, making it most helpful to future (especially short-term) air pollution and environmental health-related studies.
Camille Viatte, Rimal Abeed, Shoma Yamanouchi, William C. Porter, Sarah Safieddine, Martin Van Damme, Lieven Clarisse, Beatriz Herrera, Michel Grutter, Pierre-Francois Coheur, Kimberly Strong, and Cathy Clerbaux
Atmos. Chem. Phys., 22, 12907–12922,Short summary
Large cities can experience high levels of fine particulate matter (PM2.5) pollution linked to ammonia (NH3) mainly emitted from agricultural activities. Using a combination of PM2.5 and NH3 measurements from in situ instruments, satellite infrared spectrometers, and atmospheric model simulations, we have demonstrated the role of NH3 and meteorological conditions on pollution events occurring over Paris, Toronto, and Mexico City.
Hossain Mohammed Syedul Hoque, Kengo Sudo, Hitoshi Irie, Alessandro Damiani, Manish Naja, and Al Mashroor Fatmi
Atmos. Chem. Phys., 22, 12559–12589,Short summary
Nitrogen dioxide (NO2) and formaldehyde (HCHO) are essential trace graces regulating tropospheric ozone chemistry. These trace constituents are measured using an optical passive remote sensing technique. In addition, NO2 and HCHO are simulated with a computer model and evaluated against the observations. Such evaluations are essential to assess model uncertainties and improve their predictability. The results yielded good agreement between the two datasets with some discrepancies.
Qiansi Tu, Matthias Schneider, Frank Hase, Farahnaz Khosrawi, Benjamin Ertl, Jaroslaw Necki, Darko Dubravica, Christopher J. Diekmann, Thomas Blumenstock, and Dianjun Fang
Atmos. Chem. Phys., 22, 9747–9765,Short summary
Three-year satellite observations and high-resolution model forecast of XCH4 are used to derive CH4 emissions in the USCB region, Poland – a region of intense coal mining activities. The wind-assigned anomalies for two opposite wind directions are calculated and the estimated emission rates are very close to the inventories and in reasonable agreement with the previous studies. Our method is quite robust and can serve as a simple method to estimate CH4 or CO2 emissions for other regions.
Pu Liu, Jia Ding, Lei Liu, Wen Xu, and Xuejun Liu
Atmos. Chem. Phys., 22, 9099–9110,Short summary
Ammonia (NH3) is the important alkaline gas and the key component of fine particulate matter. We used satellite-based observations to analyze the changes in hourly NH3 concentrations and estimated surface NH3 concentrations and NH3 emissions in China. This study shows enormous potential for using satellite data to estimate surface NH3 concentrations and NH3 emissions and provides an important reference for understanding NH3 variation in China.
Yohanna Villalobos, Peter J. Rayner, Jeremy D. Silver, Steven Thomas, Vanessa Haverd, Jürgen Knauer, Zoë M. Loh, Nicholas M. Deutscher, David W. T. Griffith, and David F. Pollard
Atmos. Chem. Phys., 22, 8897–8934,Short summary
We study the interannual variability in Australian carbon fluxes for 2015–2019 derived from OCO-2 satellite data. Our results suggest that Australia's semi-arid ecosystems are highly responsive to variations in climate drivers such as rainfall and temperature. We found that high rainfall and low temperatures recorded in 2016 led to an anomalous carbon sink over savanna and sparsely vegetated regions, while unprecedented dry and hot weather in 2019 led to anomalous carbon release.
Tianlang Zhao, Jingqiu Mao, William R. Simpson, Isabelle De Smedt, Lei Zhu, Thomas F. Hanisco, Glenn M. Wolfe, Jason M. St. Clair, Gonzalo González Abad, Caroline R. Nowlan, Barbara Barletta, Simone Meinardi, Donald R. Blake, Eric C. Apel, and Rebecca S. Hornbrook
Atmos. Chem. Phys., 22, 7163–7178,Short summary
Monitoring formaldehyde (HCHO) can help us understand Arctic vegetation change. Here, we compare satellite data and model and show that Alaska summertime HCHO is largely dominated by a background from methane oxidation during mild wildfire years and is dominated by wildfire (largely from direct emission of fire) during strong fire years. Consequently, it is challenging to use satellite HCHO to study vegetation change in the Arctic region.
Maria-Elissavet Koukouli, Konstantinos Michailidis, Pascal Hedelt, Isabelle A. Taylor, Antje Inness, Lieven Clarisse, Dimitris Balis, Dmitry Efremenko, Diego Loyola, Roy G. Grainger, and Christian Retscher
Atmos. Chem. Phys., 22, 5665–5683,Short summary
Volcanic eruptions eject large amounts of ash and trace gases into the atmosphere. The use of space-borne instruments enables the global monitoring of volcanic SO2 emissions in an economical and risk-free manner. The main aim of this paper is to present its extensive verification, accomplished within the ESA S5P+I: SO2LH project, over major recent volcanic eruptions, against collocated space-borne measurements, as well as assess its impact on the forecasts provided by CAMS.
Hao Yin, Youwen Sun, Justus Notholt, Mathias Palm, and Cheng Liu
Atmos. Chem. Phys., 22, 4167–4185,Short summary
In this study, we quantity the long-term variabilities and the underlying drivers of NO2 from 2005 to 2020 over the Yangtze River Delta (YRD), one of the most densely populated and highly industrialized city clusters in China. We reveal the significant effect of the Action Plan on the Prevention and Control of Air Pollution since 2013 adopted by the Chinese government to reduce NOx pollution. Our study can improve the understanding of pollution control measures on a regional scale.
Chloé Radice, Hélène Brogniez, Pierre-Emmanuel Kirstetter, and Philippe Chambon
Atmos. Chem. Phys., 22, 3811–3825,Short summary
A novel probabilistic approach is proposed to evaluate relative humidity (RH) profiles simulated by an atmospheric model with respect to satellite-based RH defined from probability distributions. It improves upon deterministic comparisons by enhancing the information content to enable a finer assessment of each model–observation discrepancy, highlighting significant departures within a deterministic confidence range. Geographical and vertical distributions of the model biases are discussed.
Manu Anna Thomas, Abhay Devasthale, and Tiina Nygård
Atmos. Chem. Phys., 21, 16593–16608,Short summary
The impact of transported pollutants and their spatial distribution in the Arctic are governed by the local atmospheric circulation or weather states. Therefore, we investigated eight different atmospheric circulation types observed during the spring season in the Arctic. Using satellite and reanalysis datasets, this study provides a comprehensive assessment of the typical circulation patterns that can lead to enhanced or reduced pollution concentrations in the different sectors of the Arctic.
Xin Tian, Yang Wang, Steffen Beirle, Pinhua Xie, Thomas Wagner, Jin Xu, Ang Li, Steffen Dörner, Bo Ren, and Xiaomei Li
Atmos. Chem. Phys., 21, 12867–12894,Short summary
The performances of two MAX-DOAS inversion algorithms were evaluated for various aerosol pollution scenarios. One inversion algorithm is based on optimal estimation; the other uses a parameterized approach. In this analysis, three types of profile shapes for aerosols and NO2 were considered: exponential, Boltzmann, and Gaussian. The evaluation results can effectively guide the application of the two inversion algorithms in the actual atmosphere and improve the accuracy of the actual inversion.
Rebecca D. Kutzner, Juan Cuesta, Pascale Chelin, Jean-Eudes Petit, Mokhtar Ray, Xavier Landsheere, Benoît Tournadre, Jean-Charles Dupont, Amandine Rosso, Frank Hase, Johannes Orphal, and Matthias Beekmann
Atmos. Chem. Phys., 21, 12091–12111,Short summary
Our work investigates the diurnal evolution of atmospheric ammonia concentrations during a major pollution event. It analyses it in regard of both chemical (gas–particle conversion) and physical (vertical mixing, meteorology) processes in the atmosphere. These mechanisms are key for understanding the evolution of the physicochemical state of the atmosphere; therefore, it clearly fits into the scope of Atmospheric Chemistry and Physics.
Youwen Sun, Hao Yin, Cheng Liu, Emmanuel Mahieu, Justus Notholt, Yao Té, Xiao Lu, Mathias Palm, Wei Wang, Changgong Shan, Qihou Hu, Min Qin, Yuan Tian, and Bo Zheng
Atmos. Chem. Phys., 21, 11759–11779,Short summary
The variability, sources, and transport of ethane (C2H6) over eastern China from 2015 to 2020 were studied using ground-based Fourier transform infrared (FTIR) spectroscopy and GEOS-Chem simulations. C2H6 variability is driven by both meteorological and emission factors. The reduction in C2H6 in recent years over eastern China points to air quality improvement in China.
Youwen Sun, Hao Yin, Cheng Liu, Lin Zhang, Yuan Cheng, Mathias Palm, Justus Notholt, Xiao Lu, Corinne Vigouroux, Bo Zheng, Wei Wang, Nicholas Jones, Changong Shan, Min Qin, Yuan Tian, Qihou Hu, Fanhao Meng, and Jianguo Liu
Atmos. Chem. Phys., 21, 6365–6387,Short summary
This study mapped the drivers of HCHO variability from 2015 to 2019 over eastern China. Hydroxyl (OH) radical production rates from HCHO photolysis were evaluated. The relative contributions of emitted and photochemical sources to the observed HCHO abundance were analyzed. Contributions of various emission sources and geographical regions to the observed HCHO summertime enhancements were determined.
Fernando Chouza, Thierry Leblanc, Mark Brewer, Patrick Wang, Sabino Piazzolla, Gabriele Pfister, Rajesh Kumar, Carl Drews, Simone Tilmes, Louisa Emmons, and Matthew Johnson
Atmos. Chem. Phys., 21, 6129–6153,Short summary
The tropospheric ozone lidar at the JPL Table Mountain Facility (TMF) was used to investigate the impact of Los Angeles (LA) Basin pollution transport and stratospheric intrusions in the planetary boundary layer on the San Gabriel Mountains. The results of this study indicate a dominant role of the LA Basin pollution on days when high ozone levels were observed at TMF (March–October period).
Maria-Elissavet Koukouli, Ioanna Skoulidou, Andreas Karavias, Isaak Parcharidis, Dimitris Balis, Astrid Manders, Arjo Segers, Henk Eskes, and Jos van Geffen
Atmos. Chem. Phys., 21, 1759–1774,Short summary
In recent years, satellite observations have contributed to monitoring air quality. During the first COVID-19 lockdown, lower levels of nitrogen dioxide were observed over Greece by S5P/TROPOMI for March and April 2020 (than the preceding year) due to decreased transport emissions. Taking meteorology into account, using LOTOS-EUROS CTM simulations, the resulting decline due to the lockdown was estimated to range between 0 % and −37 % for the five largest Greek cities, with an average of ~ −10 %.
Tobias Borsdorff, Agustín García Reynoso, Gilberto Maldonado, Bertha Mar-Morales, Wolfgang Stremme, Michel Grutter, and Jochen Landgraf
Atmos. Chem. Phys., 20, 15761–15774,
Sören Johansson, Michael Höpfner, Oliver Kirner, Ingo Wohltmann, Silvia Bucci, Bernard Legras, Felix Friedl-Vallon, Norbert Glatthor, Erik Kretschmer, Jörn Ungermann, and Gerald Wetzel
Atmos. Chem. Phys., 20, 14695–14715,Short summary
We present high-resolution measurements of pollutant trace gases (PAN, C2H2, and HCOOH) in the Asian monsoon UTLS from the airborne limb imager GLORIA during StratoClim 2017. Enhancements are observed up to 16 km altitude, and PAN and C2H2 even up to 18 km. Two atmospheric models, CAMS and EMAC, reproduce the pollutant's large-scale structures but not finer structures. Convection is investigated using backward trajectories of the models ATLAS and TRACZILLA with advanced detection of convection.
Sora Seo, Andreas Richter, Anne-Marlene Blechschmidt, Ilias Bougoudis, and John Philip Burrows
Atmos. Chem. Phys., 20, 12285–12312,Short summary
In this study, we present spatial distributions of occurrence frequency of enhanced total BrO column and various meteorological parameters affecting it in the Arctic and Antarctic sea ice regions by using 10 years of GOME-2 measurements and meteorological model data. Statistical analysis using the long-term dataset shows clear differences in the meteorological conditions between the mean field and the situation of enhanced total BrO columns in both polar sea ice regions.
Leonie Bernet, Elmar Brockmann, Thomas von Clarmann, Niklaus Kämpfer, Emmanuel Mahieu, Christian Mätzler, Gunter Stober, and Klemens Hocke
Atmos. Chem. Phys., 20, 11223–11244,Short summary
With global warming, water vapour increases in the atmosphere. Water vapour is an important gas because it is a natural greenhouse gas and affects the formation of clouds, rain and snow. How much water vapour increases can vary in different regions of the world. To verify if it increases as expected on a regional scale, we analysed water vapour measurements in Switzerland. We found that water vapour generally increases as expected from temperature changes, except in winter.
Shannon Hicks-Jalali, Robert J. Sica, Giovanni Martucci, Eliane Maillard Barras, Jordan Voirin, and Alexander Haefele
Atmos. Chem. Phys., 20, 9619–9640,Short summary
We have calculated an 11.5-year water vapour climatology using the Raman Lidar for Meteorological Observations (RALMO), located in Payerne, Switzerland. The climatology shows that the highest water vapour concentrations are in the summer months and the lowest in the winter months. We present for the first time height-resolved water vapour trends, which show that water vapour increases specific humidity by between 5 % and 15 % per decade depending on the altitude.
Yohanna Villalobos, Peter Rayner, Steven Thomas, and Jeremy Silver
Atmos. Chem. Phys., 20, 8473–8500,Short summary
Estimated carbon fluxes for Australia are subject to considerable uncertainty. We ran simulation experiments over Australia to determine how much these uncertainties can be constrained using satellite data. We found that the satellite data has the potential to reduce these uncertainties up to 80 % across the whole continent. For 1 month, this percentage corresponds to 0.51 Pg C y-1 for Australia. This method could lead to significantly more accurate estimates of Australia's carbon budget.
Bo Zheng, Frédéric Chevallier, Philippe Ciais, Grégoire Broquet, Yilong Wang, Jinghui Lian, and Yuanhong Zhao
Atmos. Chem. Phys., 20, 8501–8510,Short summary
The Paris Climate Agreement requires all parties to report CO2 emissions regularly. Given the self-reporting nature of this system, it is critical to evaluate the emission reports with independent observation systems. Here we present the direct observations of city CO2 plumes from space and the quantification of CO2 emissions from these observations over the largest emitter country China. The emissions from 46 hot-spot regions representing 13 % of China's total emissions can be well constrained.
Jeffery Langille, Adam Bourassa, Laura L. Pan, Daniel Letros, Brian Solheim, Daniel Zawada, and Doug Degenstein
Atmos. Chem. Phys., 20, 5477–5486,Short summary
Water vapour (WV) is a highly variable and extremely important trace gas in Earth’s atmosphere. Due to its radiative and chemical properties, it is coupled to the climate in an extremely complex manner. This is especially true in the lowermost stratosphere (LMS). Despite its importance, the physical processes that control mixing and the distribution of WV in the LMS are poorly understood. This study provides observational evidence of moistening the LMS via mixing across the subtropical jet.
Youwen Sun, Cheng Liu, Lin Zhang, Mathias Palm, Justus Notholt, Hao Yin, Corinne Vigouroux, Erik Lutsch, Wei Wang, Changong Shan, Thomas Blumenstock, Tomoo Nagahama, Isamu Morino, Emmanuel Mahieu, Kimberly Strong, Bavo Langerock, Martine De Mazière, Qihou Hu, Huifang Zhang, Christof Petri, and Jianguo Liu
Atmos. Chem. Phys., 20, 5437–5456,Short summary
We present multiyear time series of ground-based Fourier-transform infrared spectroscopy measurements of HCN in densely populated eastern China. The seasonality and interannual variability of tropospheric HCN columns were investigated. The potential sources that drive the observed HCN seasonality and interannual variability were determined using a GEOS-Chem tagged CO simulation, global fire maps, and potential source contribution function values calculated using HYSPLIT back trajectories.
Enrico Dammers, Chris A. McLinden, Debora Griffin, Mark W. Shephard, Shelley Van Der Graaf, Erik Lutsch, Martijn Schaap, Yonatan Gainairu-Matz, Vitali Fioletov, Martin Van Damme, Simon Whitburn, Lieven Clarisse, Karen Cady-Pereira, Cathy Clerbaux, Pierre Francois Coheur, and Jan Willem Erisman
Atmos. Chem. Phys., 19, 12261–12293,Short summary
Ammonia is an essential molecule in the environment, but at its current levels it is unsustainable. However, the emissions are highly uncertain. We explore the use of satellites to estimate the ammonia lifetime and emissions around point sources to help improve the budget. The same method applied to different satellite instruments shows consistent results. Comparison to the emission inventories shows that those are underestimating emissions of point sources by on average a factor of 2.5.
Klemens Hocke, Leonie Bernet, Jonas Hagen, Axel Murk, Matthias Renker, and Christian Mätzler
Atmos. Chem. Phys., 19, 12083–12090,Short summary
The Tropospheric Water Radiometer (TROWARA) observed an enhanced intensity of short-term integrated water vapour (IWV) fluctuations during daytime in summer. These IWV fluctuations are possibly related to latent heat flux and thermal convective activity in the lower troposphere. The observed climatology and spectra of IWV fluctuations might be useful for modelling studies of water vapour convection in the atmospheric boundary layer at mid latitudes.
Xiaoyi Zhao, Debora Griffin, Vitali Fioletov, Chris McLinden, Jonathan Davies, Akira Ogyu, Sum Chi Lee, Alexandru Lupu, Michael D. Moran, Alexander Cede, Martin Tiefengraber, and Moritz Müller
Atmos. Chem. Phys., 19, 10619–10642,Short summary
New nitrogen dioxide (NO2) retrieval algorithms are developed for Pandora zenith-sky measurements. A column-to-surface conversion look-up table was produced for the Pandora instruments; therefore, quick and practical Pandora-based surface NO2 concentration data can be obtained for air quality monitoring purposes. It is demonstrated that the surface NO2 concentration is controlled not only by the planetary boundary layer height but also by both boundary layer dynamics and photochemistry.
Ka Lok Chan, Zhuoru Wang, Aijun Ding, Klaus-Peter Heue, Yicheng Shen, Jing Wang, Feng Zhang, Yining Shi, Nan Hao, and Mark Wenig
Atmos. Chem. Phys., 19, 10051–10071,Short summary
The paper presents long-term observations of atmospheric nitrogen dioxide (NO2) and formaldehyde (HCHO) in Nanjing using a MAX-DOAS instrument. The measurements were performed from April 2013 to February 2017. The MAX-DOAS measurements of NO2 and HCHO are used to validate OMI satellite observations and to investigate the influences of region transport of air pollutants on the air quality in Nanjing.
Olivier Bock and Ana C. Parracho
Atmos. Chem. Phys., 19, 9453–9468,Short summary
We examine the consistency of global IWV data from ERA-Interim reanalysis and 16 years of GPS observations. Representativeness differences are found to be a dominant error source, with a strong dependence on geographic, topographic, and climatic features, which explain both average and extreme differences. A methodology for reducing the representativeness errors and detecting the extreme, outlying, cases is discussed.
Maximilian Reuter, Michael Buchwitz, Oliver Schneising, Sven Krautwurst, Christopher W. O'Dell, Andreas Richter, Heinrich Bovensmann, and John P. Burrows
Atmos. Chem. Phys., 19, 9371–9383,Short summary
The quantification of anthropogenic emissions with current CO2 satellite sensors is difficult, but NO2 is co-emitted, making it a suitable tracer of recently emitted CO2. We analyze enhancements of CO2 and NO2 observed by OCO-2 and S5P and estimate the CO2 plume cross-sectional fluxes that we compare with emission databases. Our results demonstrate the usefulness of simultaneous satellite observations of CO2 and NO2 as envisaged for the European Copernicus anthropogenic CO2 monitoring mission
Luis F. Millán, Matthew D. Lebsock, and Joao Teixeira
Atmos. Chem. Phys., 19, 8491–8502,Short summary
The synergy of the collocated Advanced Microwave Scanning Radiometer (AMSR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) provides daily global estimates of marine boundary layer water vapor. AMSR provides the total column water vapor, while MODIS provides the water vapor above the cloud layers. The difference between the two gives the vapor between the surface and the cloud top, which may be interpreted as the boundary layer water vapor.
Aristeidis K. Georgoulias, Ronald J. van der A, Piet Stammes, K. Folkert Boersma, and Henk J. Eskes
Atmos. Chem. Phys., 19, 6269–6294,Short summary
In this paper, a ∼21-year self-consistent global dataset from four different satellite sensors is compiled for the first time to study the long-term tropospheric NO2 patterns and trends. A novel method capable of detecting the year when a reversal of trends happened shows that tropospheric NO2 concentrations switched from positive to negative trends and vice versa over several regions around the globe during the last 2 decades.
Elisa Carboni, Tamsin A. Mather, Anja Schmidt, Roy G. Grainger, Melissa A. Pfeffer, Iolanda Ialongo, and Nicolas Theys
Atmos. Chem. Phys., 19, 4851–4862,Short summary
The 2014–2015 Holuhraun eruption was the largest in Iceland for 200 years, emitting huge quantities of gas into the troposphere, at times overwhelming European anthropogenic emissions. Infrared Atmospheric sounding Interferometer data are used to derive the first time series of daily sulfur dioxide mass and vertical distribution over the eruption period. A scheme is used to estimate sulfur dioxide fluxes, the total erupted mass, and how long the sulfur dioxide remains in the atmosphere.
Debra Wunch, Dylan B. A. Jones, Geoffrey C. Toon, Nicholas M. Deutscher, Frank Hase, Justus Notholt, Ralf Sussmann, Thorsten Warneke, Jeroen Kuenen, Hugo Denier van der Gon, Jenny A. Fisher, and Joannes D. Maasakkers
Atmos. Chem. Phys., 19, 3963–3980,Short summary
We used five atmospheric observatories in Europe measuring total column dry-air mole fractions of methane and carbon monoxide to infer methane emissions in the area between the observatories. We find that the methane emissions are overestimated by the state-of-the-art inventories, and that this is likely due, at least in part, to the inventory disaggregation. We find that there is significant uncertainty in the carbon monoxide inventories that requires further investigation.
Klaus Gierens and Kostas Eleftheratos
Atmos. Chem. Phys., 19, 3733–3746,Short summary
We derive a new method to retrieve upper-tropospheric humidity (UTH) from High-resolution Infrared Radiation Sounder (HIRS) channel 12 brightness temperatures. With the new method we solve an old problem, namely that the wavelength change that occurred between HIRS 2 on NOAA 14 and HIRS 3 on NOAA 15 led to the retrieval of many more events with high UTH; that is, the time series shows strong jumps at high UTH values. This old problem is solved with the new retrieval.
Tobias Borsdorff, Joost aan de Brugh, Sudhanshu Pandey, Otto Hasekamp, Ilse Aben, Sander Houweling, and Jochen Landgraf
Atmos. Chem. Phys., 19, 3579–3588,Short summary
The Tropospheric Monitoring Instrument (TROPOMI) on the Sentinel-5 Precursor satellite provides carbon monoxide (CO) total column concentrations based on measurements in the 2.3 μm spectral range with a spatial resolution of 7 km x 7 km and daily global coverage. In this study, we analyzed local CO enhancements in an area around Iran from 1 November to 20 December 2017 using the WRF model and evaluated CO emissions from the cities of Tehran, Yerevan, Urmia, and Tabriz.
Xin Tian, Pinhua Xie, Jin Xu, Yang Wang, Ang Li, Fengcheng Wu, Zhaokun Hu, Cheng Liu, and Qiong Zhang
Atmos. Chem. Phys., 19, 3375–3393,Short summary
We used the MAX-DOAS instrument installed at the UCAS, Beijing, to evaluate effects on HCHO. The daily variation, transport, sources, and the effect of APEC emission control measures on HCHO were analyzed. Dependences of HCHO VCDs on wind fields indicated that the HCHO values were affected by the transport of pollutants from the south. The results from comparing the MAX-DOAS with the CAMS model indicate the CAMS model can simulate the effects of transport and the secondary sources of HCHO well.
Jerry R. Ziemke, Luke D. Oman, Sarah A. Strode, Anne R. Douglass, Mark A. Olsen, Richard D. McPeters, Pawan K. Bhartia, Lucien Froidevaux, Gordon J. Labow, Jacquie C. Witte, Anne M. Thompson, David P. Haffner, Natalya A. Kramarova, Stacey M. Frith, Liang-Kang Huang, Glen R. Jaross, Colin J. Seftor, Mathew T. Deland, and Steven L. Taylor
Atmos. Chem. Phys., 19, 3257–3269,Short summary
Both a 38-year merged satellite record of tropospheric ozone from TOMS/OMI/MLS/OMPS and a MERRA-2 GMI model simulation show large increases of 6–7 Dobson units from the Near East to India–East Asia and eastward over the Pacific. These increases in tropospheric ozone are attributed to increases in pollution over the region over the last several decades. Secondary 38-year increases of 4–5 Dobson units with both GMI model and satellite measurements occur over central African–tropical Atlantic.
Ting Wang, Pucai Wang, Nicolas Theys, Dan Tong, François Hendrick, Qiang Zhang, and Michel Van Roozendael
Atmos. Chem. Phys., 18, 18063–18078,Short summary
In the last decade, four temporal regimes of SO2 in China have been identified. After an initial rise, SO2 undergoes two sharp drops in 2007–2008 and 2014–2016, during which 5-year rebounding is sustained. Different mechanisms are tied to North and South China. The industrial emission is responsible for SO2 variation in North China, while in South China the meteorological conditions make a large contribution. The result is crucial to the understanding of SO2 changes and future polices.
Ana C. Parracho, Olivier Bock, and Sophie Bastin
Atmos. Chem. Phys., 18, 16213–16237,Short summary
Integrated water vapour from GPS observations and two modern atmospheric reanalyses were compared for 1995–2010. Means, variability and trend signs were in general good agreement. Regions and GPS stations with poor agreement were investigated further. Representativeness issues, uncertainties in reanalyses, and inhomogeneities in GPS were evidenced. Reanalyses were compared for an extended period, and a focus on north Africa and Australia highlighted the impact of dynamics on water vapour trends.
Youwen Sun, Cheng Liu, Mathias Palm, Corinne Vigouroux, Justus Notholt, Qihou Hu, Nicholas Jones, Wei Wang, Wenjing Su, Wenqiang Zhang, Changong Shan, Yuan Tian, Xingwei Xu, Martine De Mazière, Minqiang Zhou, and Jianguo Liu
Atmos. Chem. Phys., 18, 14569–14583,Short summary
The seasonal evolution of O3 and its photochemical production regime in a polluted region of eastern China between 2014 and 2017 was investigated using FTS observations. We observed a broad summer O3 maximum in Hefei, China, and the ozone production is mainly NOx limited in spring and summer and is mainly VOC or mixed VOC–NOx limited in autumn and winter.
Minqiang Zhou, Bavo Langerock, Corinne Vigouroux, Mahesh Kumar Sha, Michel Ramonet, Marc Delmotte, Emmanuel Mahieu, Whitney Bader, Christian Hermans, Nicolas Kumps, Jean-Marc Metzger, Valentin Duflot, Zhiting Wang, Mathias Palm, and Martine De Mazière
Atmos. Chem. Phys., 18, 13881–13901,Short summary
This study focuses on atmospheric CO and CH4 time series and seasonal variations on Reunion Island based on in situ and FTIR measurements from two sites, Saint Denis and Maido. Ground-based in situ and FTIR (NDACC and TCCON) measurements are used to show their complementarity with regards to obtaining the CO and CH4 concentrations at the surface and in the troposphere and stratosphere. FLEXPART and GEOS-Chem models are applied to understand the seasonal variations of CO and CH4 at this site.
Elpida Leventidou, Mark Weber, Kai-Uwe Eichmann, John P. Burrows, Klaus-Peter Heue, Anne M. Thompson, and Bryan J. Johnson
Atmos. Chem. Phys., 18, 9189–9205,Short summary
Three individual tropical tropospheric ozone (TTCO) datasets (1996–2015) retrieved with the convective-cloud differential method (Leventidou et al., 2016) have been harmonised in order to study the global and regional TTCO trends. The trends range between −4 to 4 DU per decade testing six different merging scenarios. No trend has been found for the global tropics using the preferred scenario. It is concluded that harmonisation is one of the major sources of uncertainty in the trend estimates.
Scot M. Miller, Anna M. Michalak, Vineet Yadav, and Jovan M. Tadić
Atmos. Chem. Phys., 18, 6785–6799,Short summary
NASA's Orbiting Carbon Observatory 2 (OCO-2) satellite observes CO2 in the atmosphere globally. We evaluate the extent to which current OCO-2 observations can inform scientific understanding of the biospheric carbon balance. We find that current observations are best-equipped to constrain the biospheric carbon balance across continental or hemispheric regions and provide limited information on smaller regions.
Johannes Lampel, Johannes Zielcke, Stefan Schmitt, Denis Pöhler, Udo Frieß, Ulrich Platt, and Thomas Wagner
Atmos. Chem. Phys., 18, 1671–1683,Short summary
Previous publications on the absorptions of the oxygen dimer O2–O2 (or short: O4) list absorption peaks at 328 nm and 419 nm, for which no spectrally resolved literature cross sections are available. As these absorptions potentially influence the spectral retrieval of various other trace gases, their shape and magnitude need to be quantified. We approximate the absorption peaks at 328 nm and 419 nm by their respective neighboring absorption peaks to estimate their magnitude and peak wavelength.
Fengcheng Wu, Pinhua Xie, Ang Li, Fusheng Mou, Hao Chen, Yi Zhu, Tong Zhu, Jianguo Liu, and Wenqing Liu
Atmos. Chem. Phys., 18, 1535–1554,Short summary
Investigating the temporal and spatial distribution of pollutants, emissions, and pollution transport is necessary to better understand the effect of various sources on air quality. We report on mobile differential optical absorption spectroscopy (mobile DOAS) observations of precursors SO2 and NO2 vertical columns in NCP in the summer of 2013 (from 11 June to 7 July) in this study.
Iris N. Dekker, Sander Houweling, Ilse Aben, Thomas Röckmann, Maarten Krol, Sara Martínez-Alonso, Merritt N. Deeter, and Helen M. Worden
Atmos. Chem. Phys., 17, 14675–14694,Short summary
This study estimates carbon monoxide emissions from the city of Madrid using MOPITT satellite data. There are two methods used and reviewed in this paper: a method that can only estimate a trend in the emission and a newly developed method that also includes model data from WRF to quantify the emissions. We find Madrid CO emissions to be lower by 48 % for 2002 and by 17 % for 2006 compared with the EdgarV4.2 emission inventory, but uncertainty (20 to 50 %) remains.
Zhiting Wang, Thorsten Warneke, Nicholas M. Deutscher, Justus Notholt, Ute Karstens, Marielle Saunois, Matthias Schneider, Ralf Sussmann, Harjinder Sembhi, David W. T. Griffith, Dave F. Pollard, Rigel Kivi, Christof Petri, Voltaire A. Velazco, Michel Ramonet, and Huilin Chen
Atmos. Chem. Phys., 17, 13283–13295,Short summary
In this paper we separate the biases of atmospheric methane models into stratospheric and tropospheric parts. It is observed in other studies that simulated total columns of atmospheric methane present a latitudinal bias compared to measurements. The latitudinal gradients are considered to be from the stratosphere. However, our results show that the latitudinal biases could come from the troposphere in two of three models evaluated in this study.
Arain, M. A., Blair, R., Finkelstein, N., Brook, J., and Jerrett, B.: Meteorological influences on the spatial and temporal variability of NO2 in Toronto and Hamilton, Can. Geogr.-Geogr. Can., 53, 165–190, 2009.
Boersma, K., Eskes, H., and Brinksma, E.: Error analysis for tropospheric NO2 retrieval from space, J. Geophys. Res.-Atmos., 109, D04311, https://doi.org/10.1029/2003JD003962, 2004.
Boersma, K. F., Eskes, H. J., Veefkind, J. P., Brinksma, E. J., van der A, R. J., Sneep, M., van den Oord, G. H. J., Levelt, P. F., Stammes, P., Gleason, J. F., and Bucsela, E. J.: Near-real time retrieval of tropospheric NO2 from OMI, Atmos. Chem. Phys., 7, 2103–2118, https://doi.org/10.5194/acp-7-2103-2007, 2007.
Boersma, K. F., Jacob, D. J., Bucsela, E. J., Perring, A. E., Dirksen, R., van der A, R. J., Yantosca, R. M., Park, R. J., Wenig, M. O., Bertram, T. H., and Cohen, R. C.: Validation of OMI tropospheric NO2 observations during INTEX-B and application to constrain NOx emissions over the Eastern United States and Mexico, Atmos. Environ., 42, 4480–4497, https://doi.org/10.1016/j.atmosenv.2008.02.004, 2008.
Boersma, K. F., Jacob, D. J., Trainic, M., Rudich, Y., DeSmedt, I., Dirksen, R., and Eskes, H. J.: Validation of urban NO2 concentrations and their diurnal and seasonal variations observed from the SCIAMACHY and OMI sensors using in situ surface measurements in Israeli cities, Atmos. Chem. Phys., 9, 3867–3879, https://doi.org/10.5194/acp-9-3867-2009, 2009.
Bovensmann, H., Burrows, J. P., Buchwitz, M., Frerick, J., Noel, S., Rozanov, V. V., Chance, K., and Goede, A. P. H.: SCIAMACHY: mission objectives and measurement modes, J. Atmos. Sci., 56, 127–150, 1999.
Brook, J. R., Burnett, R. T., Dann, T. F., Cakmak, S., Goldberg, M. S., Fan, X., and Wheeler, A. J.: Further interpretation of the acute effect of nitrogen dioxide observed in Canadian time-series studies, J. Expo. Sci. Env. Epid., 17, S36–S44, https://doi.org/10.1038/sj.jes.7500626, 2007.
Bucsela, E., Celarier, E., Wenig, M., Gleason, J., Veefkind, J., Boersma, K., and Brinksma, E.: Algorithm for NO2 vertical column retrieval from the Ozone Monitoring Instrument, IEEE T. Geosci. Remote, 44, 1245–1258, https://doi.org/10.1109/TGRS.2005.863715, 2006.
Bucsela, E. J., Perring, A. E., Cohen, R. C., Boersma, K. F., Celarier, E. A., Gleason, J. F., Wenig, M. O., Bertram, T. H., Wooldridge, P. J., Dirksen, R., and Veefkind, J. P.: Comparison of tropospheric NO2 from in situ aircraft measurements with near-real-time and standard product data from OMI, J. Geophys. Res.-Atmos., 113, D16S31, https://doi.org/10.1029/2007JD008838, 2008.
Burrows, J., Weber, M., Buchwitz, M., Rozanov, V., Ladstatter-Weissenmayer, A., Richter, A., DeBeek, R., Hoogen, R., Bramsteadt, K., Eichmann, K., Eisinger, M., and Perner, D.: The Global Ozone Monitoring Experiment (GOME): mission concept and first scientific results, J. Atmos. Sci., 56, 151–175, 1999.
Celarier, E. A., Brinksma, E. J., Gleason, J. F., Veefkind, J. P., Cede, A., Herman, J. R., Ionov, D., Goutail, F., Pommereau, J. P., Lambert, J. C., van Roozendael, M., Pinardi, G., Wittrock, F., Schönhardt, A., Richter, A., Ibrahim, O. W., Wagner, T., Bojkov, B., Mount, G., Spinei, E., Chen, C. M., Pongetti, T. J., Sander, S. P., Bucsela, E. J., Wenig, M. O., Swart, D. P. J., Volten, H., Kroon, M., and Levelt, P. F.: Validation of Ozone Monitoring Instrument nitrogen dioxide columns, J. Geophys. Res., 113, D15S15, https://doi.org/10.1029/2007JD008908, 2008.
Clark, N. A., Demers, P. A., Karr, C. J., Koehoorn, M., Lencar, C., Tamburic, L., and Brauer, M.: Effect of early life exposure to air pollution on development of childhood asthma, Environ. Health Persp., 118, 284–290, https://doi.org/10.1289/ehp.0900916, 2010.
Hains, J. C., Boersma, K. F., Kroon, M., Dirksen, R. J., Cohen, R. C., Perring, A. E., Bucsela, E., Volten, H., Swart, D. P. J., Richter, A., Wittrock, F., Schönhardt, A., Wagner, T., Ibrahim, O. W., van Roozendael, M., Pinardi, G., Gleason, J. F., Veefkind, J. P., and Levelt, P.: Testing and improving OMI DOMINO tropospheric NO2 using observations from the DANDELIONS and INTEX-B validation campaigns, J. Geophys. Res.-Atmos., 115, D05301, https://doi.org/10.1029/2009JD012399, 2010.
Halla, J. D., Wagner, T., Beirle, S., Brook, J. R., Hayden, K. L., O'Brien, J. M., Ng, A., Majonis, D., Wenig, M. O., and McLaren, R.: Determination of tropospheric vertical columns of NO2 and aerosol optical properties in a rural setting using MAX-DOAS, Atmos. Chem. Phys. Discuss., 11, 13035–13097, https://doi.org/10.5194/acpd-11-13035-2011, 2011.
Herron-Thorpe, F. L., Lamb, B. K., Mount, G. H., and Vaughan, J. K.: Evaluation of a regional air quality forecast model for tropospheric NO2 columns using the OMI/Aura satellite tropospheric NO2 product, Atmos. Chem. Phys., 10, 8839–8854, https://doi.org/10.5194/acp-10-8839-2010, 2010.
Jerrett, M., Finkelstein, M. M., Brook, J. R., Arain, M. A., Kanaroglou, P., Stieb, D. M., Gilbert, N. L., Verma, D., Finkelstein, N., Chapman, K. R., and Sears, M. R.: A cohort study of traffic-related air pollution and mortality in Toronto, Ontario, Canada, Environ. Health Persp., 117, 772–777, https://doi.org/10.1289/ehp.11533, 2009.
Kim, S. W., Heckel, A., Frost, G. J., Richter, A., Gleason, J., Burrows, J. P., McKeen, S., Hsie, E. Y., Granier, C., and Trainer, M.: NO2 columns in the Western United States observed from space and simulated by a regional chemistry model and their implications for NOx emissions, J. Geophys. Res., 114, D11301, https://doi.org/10.1029/2008JD011343, 2009.
Kramer, L. J., Leigh, R. J., Remedios, J. J., and Monks, P. S.: Comparison of OMI and ground-based in situ and MAX-DOAS measurements of tropospheric nitrogen dioxide in an urban area, J. Geophys. Res.-Atmos., 113, D16S39, https://doi.org/10.1029/2007JD009168, 2008.
Lamsal, L. N., Martin, R. V., van Donkelaar, A., Steinbacher, M., Celarier, E. A., Bucsela, E., Dunlea, E. J., and Pinto, J. P.: Ground-level nitrogen dioxide concentrations inferred from the satellite-borne Ozone Monitoring Instrument, J. Geophys. Res.-Atmos., 113, D16308, https://doi.org/10.1029/2007JD009235, 2008.
Lamsal, L. N., Martin, R. V., van Donkelaar, A., Celarier, E. A., Bucsela, E. J., Boersma, K. F., Dirksen, R., Luo, C., and Wang, Y.: Indirect validation of tropospheric nitrogen dioxide retrieved from the OMI satellite instrument: insight into the seasonal variation of nitrogen oxides at northern midlatitudes, J. Geophys. Res.-Atmos., 115, D05302, https://doi.org/10.1029/2009JD013351, 2010.
Lenters, V., Uiterwaal, C. S., Beelen, R., Bots, M. L., Fischer, P., Brunekreef, B., and Hoek, G.: Long-term exposure to air pollution and vascular damage in young adults, Epidemiology, 21, 512–520, https://doi.org/10.1097/EDE.0b013e3181dec3a7, 2010.
Levelt, P., van den Oord, G., Dobber, M., Malkki, A., Visser, H., de Vries, J., Stammes, P., Lundell, J., and Saari, H.: The Ozone Monitoring Instrument, IEEE T. Geosci. Remote, 44, 1093–1101, https://doi.org/10.1109/TGRS.2006.872333, 2006.
Levy, I., Makar, P. A., Sills, D., Zhang, J., Hayden, K. L., Mihele, C., Narayan, J., Moran, M. D., Sjostedt, S., and Brook, J.: Unraveling the complex local-scale flows influencing ozone patterns in the southern Great Lakes of North America, Atmos. Chem. Phys., 10, 10895–10915, https://doi.org/10.5194/acp-10-10895-2010, 2010.
Makar, P. A., Gong, W., Mooney, C., Zhang, J., Davignon, D., Samaali, M., Moran, M. D., He, H., Tarasick, D. W., Sills, D., and Chen, J.: Dynamic adjustment of climatological ozone boundary conditions for air-quality forecasts, Atmos. Chem. Phys., 10, 8997–9015, https://doi.org/10.5194/acp-10-8997-2010, 2010.
Martin, R. V., Chance, K., Jacob, D. J., Kurosu, T. P., Spurr, R. J. D., Bucsela, E., Gleason, J. F., Palmer, P. I., Bey, I., Fiore, A. M., Li, Q., Yantosca, R. M., and Koelemeijer, R. B. A.: An improved retrieval of tropospheric nitrogen dioxide from GOME, J. Geophys. Res., 107, 4437, https://doi.org/10.1029/2001JD001027, 2002.
MoE: Air Quality in Ontario 2008 Report, available at: http://www.ene.gov.on.ca/publications/7356e.pdf (last access: August 2010), 2008.
NOAA: Lake Erie Temperature Normals, available at: http://www.erh.noaa.gov/buf/laketemps/lktemp.html (last access: December 2010), 2010.
O'Byrne, G., Martin, R. V., van Donkelaar, A., Joiner, J., and Celarier, E. A.: Surface reflectivity from the Ozone Monitoring Instrument using the Moderate Resolution Imaging Spectroradiometer to eliminate clouds: effects of snow on ultraviolet and visible trace gas retrievals, J. Geophys. Res., 115, D17305, https://doi.org/10.1029/2009JD013079, 2010.
Ordóñez, C., Richter, A., Steinbacher, M., Zellweger, C., Nuss, H., Burrows, J., and Prevot, A.: Comparison of 7 years of satellite-borne and ground-based tropospheric NO2 measurements around Milan, Italy, J. Geophys. Res.-Atmos., 111, D05310, https://doi.org/10.1029/2005JD006305, 2006.
Russell, A. R., Valin, L. C., Bucsela, E. J., Wenig, M. O., and Cohen, R. C.: Space-based constraints on spatial and temporal patterns of NOx emissions in California, 2005–2008, Environ. Sci. Technol., 44, 3608–3615, https://doi.org/10.1021/es903451j, 2010.
Ryerson, T., Williams, E., and Fehsenfeld, F.: An e?cient photolysis system for fast-response NO2 measurements, J. Geophys. Res.-Atmos., 105, 26447–26461, 2000.
Statistics Canada: 2006 Census of Canada Census Profiles Marital status, common-law status, families, dwellings, and households Tables: Profile of Marital Status, Common-law Status, Families, Dwellings and Households, for Census Metropolitan Areas and Census Agglomerations, 2006 Census., Tech. rep., Statistics Canada, 2006.
Steinbacher, M., Zellweger, C., Schwarzenbach, B., Bugmann, S., Buchmann, B., Ordonez, C., Prevot, A. S. H., and Hueglin, C.: Nitrogen oxide measurements at rural sites in Switzerland: Bias of conventional measurement techniques, J. Geophys. Res.-Atmos., 112, D11307, https://doi.org/10.1029/2006JD007971, 2007.
US Census Bureau: Table 1. Annual Estimates of the Population of Metropolitan and Micropolitan Statistical Areas: 1 April 2000 to 1 July 2009 (CBSA-EST2009-01), available at: http://www.census.gov/popest/metro/CBSA-est2009-annual.html (last access: October 2010), 2010.
Wenig, M., Cede, A., Bucsela, E., Celarier, E., Boersma, K., Veefkind, J., Brinksma, E., Gleason, J., and Herman, J.: Validation of OMI tropospheric NO2 column densities using direct-Sun mode Brewer measurements at NASA Goddard Space Flight Center, J. Geophys. Res.-Atmos., 113, D16S45, https://doi.org/10.1029/2007JD008988, 2008.
Winer, A., Peters, J., Smith, J., and Pitts, J.: Response Of Commercial Chemiluminescent NO-NO2 Analyzers To Other Nitrogen-Containing Compounds, Environ. Sci. Technol., 8, 1118–1121, https://doi.org/10.1021/es60098a004, 1974.
- Metadata XML