1Research Center for Air Pollution and Health; Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Education, College of Environment and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, P.R. China
2College of Science and Technology, Hebei Agricultural University, Baoding, Hebei 071000, P.R. China
3Chinese Academy of Meteorological Sciences, China Meteorological Administration, Beijing 100081, China
4State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences (CAS), Beijing 100029, China
5University of Chinese Academy of Sciences, Beijing 100049, China
6Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China
7Chinese Research Academy of Environmental Sciences, Beijing 100012, China
8State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
9State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
10Center for Environmental Measurement and Modeling, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
11Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
12Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 29 91125, USA
1Research Center for Air Pollution and Health; Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Education, College of Environment and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, P.R. China
2College of Science and Technology, Hebei Agricultural University, Baoding, Hebei 071000, P.R. China
3Chinese Academy of Meteorological Sciences, China Meteorological Administration, Beijing 100081, China
4State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences (CAS), Beijing 100029, China
5University of Chinese Academy of Sciences, Beijing 100049, China
6Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China
7Chinese Research Academy of Environmental Sciences, Beijing 100012, China
8State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
9State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
10Center for Environmental Measurement and Modeling, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
11Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
12Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 29 91125, USA
Received: 17 Mar 2022 – Discussion started: 29 Mar 2022
Abstract. Condensable particulate matter (CPM) emitted from stationary combustion and mobile sources exhibits high emissions and a large proportion of organic components. However, CPM is not generally measured when conducting emission surveys of PM in most countries, including China. Consequently, previous emission inventories have not included emission rates for CPM. Here we construct an emission inventory of CPM in China with a focus on organic aerosols (OA) based on collected CPM emission information. Results show that OA emissions are enhanced twofold after the inclusion of CPM in a new China inventory for the years 2014 and 2017. Considering organic CPM emissions and model representations of secondary OA (SOA) formation from CPM, here a series of sensitivity cases have been simulated using the three-dimensional Community Multiscale Air Quality (CMAQ) model to estimate the contributions of CPM emissions to atmospheric OA and fine PM (PM2.5) concentrations in China. Compared with observations during a haze episode from October 14 to November 14, 2014, at a Beijing site, estimates of temporal average primary OA (POA) and SOA concentrations are greatly improved after including the CPM effects. These scenarios demonstrated the significant contributions of CPM emissions from stationary combustion and mobile sources to POA (53 ~ 86 %), SOA (48 ~ 67 %), and total OA concentrations (50 ~ 78 %). Furthermore, contributions of CPM emissions to total OA concentrations were demonstrated over the major 2+26 cities of Beijing-Tianjin-Hebei region (BTH2+26 cities) in December 2018, with average contributions up to 55 %, 58 %, 60 %, and 57 % for Handan, Shijiazhuang, Xingtai, and Dezhou, respectively. Correspondingly, the inclusion of CPM emissions also narrowed the gap between simulated and observed PM2.5 concentrations over the BTH2+26 cities. These results improve the simulation performance of atmospheric OA and PM2.5, and may provide important implications for the sources of OA.
Li et al. constructed an emission inventory for condensable particulate matter for China and evaluated its impact on the simulation of organic aerosol and PM2.5. The study provides useful information on how CPM emissions (which are conventionally not measured in emission studies) affect ambient concentrations. However, I find the paper difficult to follow mainly because the method descriptions are not well organized. For example, the authors did not explicitly state their operational definitions for OA, POA, SOA, FPM, CPM, OMlsi, OM(C*<100), SVOC, and their relationships, which cause confusion. For example, I am confused about whether CPM emissions are accounted for as only primary emissions or also as secondary emissions in the emission inventory? And whether this inventory assumes that all CPM are organic? Whether E_OA include E_OMlsi (Eq.1-3) or do they represent non-overlapping components? Clearly describing what the authors actually did and meant would definitely help assess the scientific value of this study.Â
Minor comments
Line 76 ambiguous meaning of "negative impact". Change to "negative radiative forcing".
Line 98: unclear what is "inapplicability of parameter localizations". Do you mean there is a lack of local emission factors?
Line 109: "totally" -> "completely"
Line 134: the ambiguous expression "more than 50% of organic composition were measured in CPM". Please rephrase.
Line 148: "largely" -> "greatly" or "substantially"
Table S3 should list the measurement methods that these studies used.
Line 172 & Line 188-193: Please explain what is the difference between OA(CPM) and OM_lsi(CPM). Do you consider OA(CPM)-OM_lsi(CPM) as POA(CPM)?Â
Line 196: what is the relative importance of stationary combustion vs. vehicles?
Line 216-217 & 270-273: what are the bases of these scaling factors? I thought you already derived emissions based on Eq.1-3. Why do you need to scale with respect to POA emissions?
Line 318-319: C*<=100 or C*<=10? Also state the unit of C*.
Line 322: The OA emissions reported here are for what geographical region?
Section 3.2. These evaluations are not relevant and are just distractive. I'd suggest removing the section or putting it in the supplementary material.
Line 369-372. Use "episode" instead of "process".
Section 3.3. How do the observations distinguish POA and SOA? Their operational definition should be introduced, as sometimes it is not so straightforward to compare to simulations.
Line 461-462: Why do you think it is more likely due to meteorological factors, rather than that your emissions are still underestimated and that there are still missing SOA pathways?
Figure 1. Explain in the caption what the color shading represents
This study constructed an emission inventory of Condensable particulate matter (CPM) in China with a focus on organic aerosols (OA) based on collected CPM emission information. Results show that OA emissions are enhanced twofold after the inclusion of CPM in a new China inventory for the years 2014 and 2017. Sensitivity cases demonstrated the significant contributions of CPM emissions from stationary combustion and mobile sources to POA, SOA, and total OA concentrations.
This study constructed an emission inventory of Condensable particulate matter (CPM) in China...
