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学者姓名：魏巍
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Abstract ：
The ambient levels of NO2 in urban areas in China in recent years have generally shown a downward trend, but high NO2 concentrations still exist under certain conditions, and the causes for such phenomenon and its impact on air quality remain unclear. Taking Dongying, a typical petrochemical city in the Bohai Bay of China, as an example, this paper analyzed the influence of NO2 on urban air quality and investigated the causes for the formation of NO2 with high concentrations. The results indicated that higher daily NO2 concentrations (>40 mu g/m(3)) mainly occurred during January-April and September-December each year, and higher hourly NO2 concentrations mainly occurred during the nighttime and morning rush hour in Dongying from 2017 to 2023. With the increase in daily NO2 concentrations, the daily air pollution levels showed a general increasing trend from 2017 to 2023. The occurrence of high NO2 values in Dongying was affected by the combination of unfavorable meteorological conditions, local emissions and regional transports, and localized atmospheric chemical generation. High-pressure and uniform-pressure weather patterns in 2017-2022, along with land-sea breeze circulation in 2022, contribute to high NO2 concentrations in Dongying. Boundary layer heights (BLH) in spring (-0.43) and winter (-0.36), wind direction in summer (0.21), and temperature in autumn (-0.46) are the primary meteorological factors driving NO2-HH (High hourly NO2 values), while BLH (-0.47) is the main cause for NO2-HD (High daily NO2 values). The titration reaction between NO with O-3 is the main cause for NO2-HH in spring, summer and autumn, and photochemical reactions of aromatics have a significant influence on NO2-HD. NOx emissions from the thermal power and petrochemical industry in Dongying and air pollution transports from western and southwestern Shandong Province (throughout the year) and from the Bohai Sea (during spring and summer) had serious adverse impact on high NO2 values in 2022. The results of the study could help to provide a scientific basis for the control of NO2 and the continuous improvement of air quality in Dongying and similar petrochemical cities.
Keyword ：
NO2 pollution characteristics NO2 pollution characteristics impacts on air quality impacts on air quality Bohai Bay region of China Bohai Bay region of China causes for high NO2 values causes for high NO2 values pollution meteorological conditions pollution meteorological conditions
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| GB/T 7714 | Gao, Xiaoshuai , An, Cong , Yan, Yongxin et al. Impacts of NO2 on Urban Air Quality and Causes of Its High Ambient Levels: Insights from a Relatively Long-Term Data Analysis in a Typical Petrochemical City in the Bohai Bay Region, China [J]. | TOXICS , 2025 , 13 (3) . |
| MLA | Gao, Xiaoshuai et al. "Impacts of NO2 on Urban Air Quality and Causes of Its High Ambient Levels: Insights from a Relatively Long-Term Data Analysis in a Typical Petrochemical City in the Bohai Bay Region, China" . | TOXICS 13 . 3 (2025) . |
| APA | Gao, Xiaoshuai , An, Cong , Yan, Yongxin , Ji, Yuanyuan , Wei, Wei , Xue, Likun et al. Impacts of NO2 on Urban Air Quality and Causes of Its High Ambient Levels: Insights from a Relatively Long-Term Data Analysis in a Typical Petrochemical City in the Bohai Bay Region, China . | TOXICS , 2025 , 13 (3) . |
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Abstract ：
Atmospheric carbonyl compounds have significant impacts on the atmospheric environment and human health, making the selection of appropriate analytical techniques crucial for accurately detecting these compounds in specific environments. Based on extensive literature research, this study summarized the development history, relevant features, and applicable scenarios of the main analytical techniques for atmospheric carbonyl compounds; pointed out the main problems and challenges in this field; and discussed the needs and prospects of future research and application. It was found that the direct sampling methods of atmospheric carbonyl compounds were applicable to low-molecular-weight carbonyl species with low reactivity, low boiling points, high polarity, and high volatility, while indirect sampling methods were suitable for a wider range and various types and phases of species. For formaldehyde, offline detection was primarily influenced by chemical reagents and reaction conditions, whereas online monitoring relied on sufficiently stable operating environments. For multiple carbonyl compounds, offline detection results were greatly influenced by detectors coupled with chromatography, whereas online monitoring techniques were applicable to all types of volatile organic compounds (VOCs), including some carbonyl compounds, providing higher temporal resolution and improved isomer identification with the development of online mass spectrometry. The combined use of proton transfer reaction-mass spectrometry (PTR-MS) and liquid chromatography-mass spectrometry (GC-MS) was suitable for the detection of carbonyl compounds in atmospheric photochemical smog chamber simulation studies. Currently, offline analytical techniques for carbonyl compounds require significant time and advanced experimental skills for multiple optimization experiments to detect a broader range of species. Online monitoring techniques face challenges such as poor stability and limited species coverage. In smog chamber simulation studies, the detection of carbonyl compounds is heavily influenced by both the sampling system and the chamber itself. Future efforts should focus on improving the environmental adaptability and automation of carbonyl compound analytical techniques, the synergistic use of various techniques, developing new sampling systems, and reducing the impact of the chamber itself on carbonyl compound detection, in order to enhance detection sensitivity, selectivity, time resolution, accuracy, and operability.
Keyword ：
online analytical methods online analytical methods offline analytical methods offline analytical methods prospect prospect sampling methods sampling methods atmospheric carbonyls atmospheric carbonyls problems and challenges problems and challenges
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| GB/T 7714 | Gao, Xiaoshuai , Zhang, Xin , Nie, Yan et al. Analytical Methods for Atmospheric Carbonyl Compounds: A Review [J]. | ATMOSPHERE , 2025 , 16 (1) . |
| MLA | Gao, Xiaoshuai et al. "Analytical Methods for Atmospheric Carbonyl Compounds: A Review" . | ATMOSPHERE 16 . 1 (2025) . |
| APA | Gao, Xiaoshuai , Zhang, Xin , Nie, Yan , Bao, Jiemeng , Li, Junling , Gao, Rui et al. Analytical Methods for Atmospheric Carbonyl Compounds: A Review . | ATMOSPHERE , 2025 , 16 (1) . |
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Abstract ：
Ozone (O3) pollution in city level is a complex issue that arises not only from local photochemistry process but also involves mid- or long-range O3 transport. In this study, we developed a modeling approach to dynamically quantifying local photochemical process (indicated as Chem_O3) and estimating its role in surface O3 pollution in city level. The work was conducted on North BTH of China for summer of 2022 and mainly focused on the urban areas, in which surface O3 usually as the most dominant air pollutants to harm population health. The method was constructed via establishing the hourly response of locally-formed O3 to locally-released NOx (R O3-NO2 , ppb & sdot;ppb-1) based on ISAM simulations and then combining R O3-NO2 and ambient NO2 levels to quantify time- varying Chem_O3. The results showed that the monthly mean of Chem_O3 and its proportion to actual O3 (Chem%) was 17.9-26.0 ppb and 46.7%-62.6% in major urban areas of North BTH, following the order of mega- city > industrialized city > normal city > forest city. Moreover, daily Chem% presented the different trend with daily O3 in these study areas, slight-positive for mega-cities, but moderate or strong-negative for most other cities. Specially, our developed method could additionally disentangling O3 physical transport among the studied cities, and we found the inflow of O3 was much lower than the outflow of O3 for two mega-cities, while it was opposite in other cities. We think this method could clearly point out the role of local photochemistry control in O3 reduction, which could help city environment managers to develop scientific and effective policy strategies to cope with ozone-related problems.
Keyword ：
China China O 3 pollution O 3 pollution NOx NOx CMAQ-ISAM CMAQ-ISAM Local photochemistry Local photochemistry
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| GB/T 7714 | Chen, Saisai , Wei, Wei , Wang, Chuanda et al. A modeling approach to dynamically estimating local photochemistry process and its contribution to surface O3 pollution [J]. | JOURNAL OF ENVIRONMENTAL MANAGEMENT , 2025 , 373 . |
| MLA | Chen, Saisai et al. "A modeling approach to dynamically estimating local photochemistry process and its contribution to surface O3 pollution" . | JOURNAL OF ENVIRONMENTAL MANAGEMENT 373 (2025) . |
| APA | Chen, Saisai , Wei, Wei , Wang, Chuanda , Wang, Xiaoqi , Zhou, Chunyan , Cheng, Shuiyuan . A modeling approach to dynamically estimating local photochemistry process and its contribution to surface O3 pollution . | JOURNAL OF ENVIRONMENTAL MANAGEMENT , 2025 , 373 . |
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Abstract ：
This study mainly developed an estimate method for photochemical ozone (O3) production from urban plumes in hot season, through simulating O3 evolution from precursors locally emitted and determining the real-field O3 increment reactivity (IR) of volatile organic compounds (VOCs) based on the box chemical model. Our simulation on June-2019 indicated that Beijing local emissions produced O3 at the rate of 0.7-9.2 ppb/h and led to an O3 increase of 48.9 ppb during 05:00-18:00, accounting for 68.3% of the observed O3 increase. The maximum level and production rate of simulated O3 showed a linear response to VOCs, therefore we can use VOCs levels in urban plumes to quantify O3 formation in summer. The IR (g O3 formed per g VOCs) was calculated on the actual precursor and meteorology condition of this megacity, 0.12-4.90 g/g for individual VOCs and 1.49 g/g for comprehensive TVOCs. The weighted average of individual IRs agreed well with that of TVOCs, but these IRs were 34.5% of MIR values that were widely used in references. It's noteworthy that these IRs had greater sensitivity to precursor levels, and broadly remained stable under the fixed VOCs:NOx. Considering the synchronous reductions of precursors in Beijing, we applied these IRs to quantify chemical O3 evolution from Beijing local emissions in summer of recent years, declining from 63.5 ppb in 2016 to 44.0 ppb in 2020 for June. The contributions of the diagnosed chemical O3 to Beijing O3 better matched with the atmospheric transport paths on daily basis, higher than 100% when the transport paths starting from the clean neighbor cities, but lower to 45%- 66% when the transport paths originating from the highly-polluted neighbor cities. This consistence indicated the reliability of our IR calculation method for quickly estimating chemical O3 production of urban plumes in summer.
Keyword ：
VOCs VOCs MCM MCM Urban plumes Urban plumes Photochemical O 3 Photochemical O 3 Increment reactivity Increment reactivity
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| GB/T 7714 | Chen, Saisai , Wei, Wei , Chen, Kang et al. Diagnosis of photochemical O3 production of urban plumes in summer via developing the real-field IRs of VOCs: A case study in Beijing of China [J]. | ENVIRONMENTAL POLLUTION , 2023 , 318 . |
| MLA | Chen, Saisai et al. "Diagnosis of photochemical O3 production of urban plumes in summer via developing the real-field IRs of VOCs: A case study in Beijing of China" . | ENVIRONMENTAL POLLUTION 318 (2023) . |
| APA | Chen, Saisai , Wei, Wei , Chen, Kang , Wang, Xiaoqi , Han, Lihui , Cheng, Shuiyuan . Diagnosis of photochemical O3 production of urban plumes in summer via developing the real-field IRs of VOCs: A case study in Beijing of China . | ENVIRONMENTAL POLLUTION , 2023 , 318 . |
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Abstract ：
Coke making is extremely problematic from the environment and health perspectives, as the massive hazardous volatile organic compounds (HVOCs) being driven off during the coking process. Here, we conducted a health risk assessment study on coking workers, through on-situ HVOCs measurements and questionnaire investigation on activity time parameters and protection measures. The ambient HVOCs at major working stations were 58.4-376.5 mu g/m3 with relative deviation of 59.4% for the certain station. The total working hours during career would reach 43283-51695 h, and protection efficiency (PE) to resist HVOCs inhalation ranged from 16% to 87%. According to the exposure evaluation model recommended by the U.S. EPA, there was little non-cancer risk for the workers at most positions with hazard quotient (HQ) value of less than 1; however, the cancer risk widely existed with lifetime cancer risk (LCR) value of 3.6-15.0 x 10-6, in which benzene, 1,2-dichloropropane, 1,2-dichloroethane, and 1,3-butadiene were dominant inducers. The cancer risk regarding the large plants was about 28.6% lower compared to the small and medium plants, due to the greater PE. In terms of the response of the health risk to exposure duration (ED, working years) and PE, non-cancer risk effectively responded only for the byproduct recovery stations, while cancer risk more sensitively responded for all stations. Health risk manage-ment therefore is essential, and the potential health hazards can be avoided by limiting ED and strengthening PE. For workers in coking, byproduct recovery and office areas, the PE should be higher than 93.8%, 97.7% and 77.3% under the ED of 20 years, the ED in three areas should be lower than 12.5 years, 4.5 years and 30 years under PE of 90%, respectively.
Keyword ：
Non-cancer risk Non-cancer risk HVOCs exposure HVOCs exposure Coking industry Coking industry Cancer risk Cancer risk Security suggestion Security suggestion
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| GB/T 7714 | Cheng, Long , Wei, Wei , Guo, Aimin et al. Health risk assessment of hazardous VOCs and its associations with exposure duration and protection measures for coking industry workers [J]. | JOURNAL OF CLEANER PRODUCTION , 2022 , 379 . |
| MLA | Cheng, Long et al. "Health risk assessment of hazardous VOCs and its associations with exposure duration and protection measures for coking industry workers" . | JOURNAL OF CLEANER PRODUCTION 379 (2022) . |
| APA | Cheng, Long , Wei, Wei , Guo, Aimin , Zhang, Chengzhou , Sha, Kechang , Wang, Ruipeng et al. Health risk assessment of hazardous VOCs and its associations with exposure duration and protection measures for coking industry workers . | JOURNAL OF CLEANER PRODUCTION , 2022 , 379 . |
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Abstract ：
Volatile organic compounds (VOCs) have been explicitly required to be controlled by national or local governments to tackle heavy PM2.5 pollution in China. However, the role of VOCs chemistry in PM2.5 is still far away from being fully understood. In this study, we selected a typically industrialized city of China, conducted VOCs online measurements in July and December of 2020, estimated VOCs chemical losses, and explored their impacts on PM2.5 in the real atmosphere. Our measurements totally detected the mixing ratios of 53 VOCs species, sum of which reaching 20.8 +/- 9.1 ppb and 45.5 +/- 19.8 ppb in July and December respectively. Based on the change in the relative abundance of various VOCs species with different reactivity, daily OH exposure and daily O3 exposure (molecules.s.cm- 3) were estimated, respectively with the mean value of 11.0 x 10(10) and 5.2 x 10(15) in July, 5.9 x 10(10) and 3.1 x 10(15) in December. Thus, there were about 6.7 +/- 3.2 ppb and 11.1 +/- 5.0 ppb VOCs chemically lost in July and December, with the average loss ratio of 29.7% and 19.3% in respective. In July, PM(2.5)in the range of 20-60 mu gm(-3) positively responded to VOCs loss ratios, and high PM2.5 values were always accompanied by higher VOCs losses instead of high CO levels; but their relationship became negative in December when PM2.5 in the range of 40-150 mu g m(-3), and extremely high PM2.5 values happened in high CO conditions instead of high VOCs losses conditions. Moreover, PM2.5 measurements in this city also showed an apparent upward trend in OC/EC with PM2.5 in summer, but a slight downward trend in winter. These all indicated that in the conditions of stronger solar radiations (summer) and low-middle aerosol loads, VOCs chemistry played the important role in PM(2.5)increasing through contributing SOA; but in the conditions of lower solar radiations (winter) and heavy aerosol loads, VOCs chemistry was greatly weakened and had the minor impact on PM2.5 increasing. The measure involving VOCs reduction to alleviate PM2.5 pollution in winter needs to be cautiously considered and examined.
Keyword ：
Chemical loss Chemical loss PM2.5 PM2.5 OH oxidation OH oxidation VOCs VOCs O-3 oxidation O-3 oxidation
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| GB/T 7714 | Wei, Wei , Chen, Saisai , Wang, Yue et al. The impacts of VOCs on PM2.5 increasing via their chemical losses estimates: A case study in a typical industrial city of China [J]. | ATMOSPHERIC ENVIRONMENT , 2022 , 273 . |
| MLA | Wei, Wei et al. "The impacts of VOCs on PM2.5 increasing via their chemical losses estimates: A case study in a typical industrial city of China" . | ATMOSPHERIC ENVIRONMENT 273 (2022) . |
| APA | Wei, Wei , Chen, Saisai , Wang, Yue , Cheng, Long , Wang, Xiaoqi , Cheng, Shuiyuan . The impacts of VOCs on PM2.5 increasing via their chemical losses estimates: A case study in a typical industrial city of China . | ATMOSPHERIC ENVIRONMENT , 2022 , 273 . |
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Abstract ：
Co-pollution of surface O-3 and PM2.5 has become the most predominant type of air pollutions in Beijing-Tianjin-Hebei region in the hot season since 2017, particularly in May-July. Analysis based on observational data showed that co-pollution was always accompanied by high temperature, moderate relative humidity, extremely high SO2, and higher NO2. We also found that the meteorology and precursor dependence of O-3 was similar between co-pollution and O-3- single pollution. While PM2.5 in co-pollution was more related to temperature, relative humidity, and precursors, that in PM2.5-singe pollution were more related to small winds. These results indicate that co-pollution seemed to be more affected by atmospheric chemistry. According to the PM2.5 components, secondary inorganic aerosols (SIA) composed 44.3-48.7% of PM2.5 in co-pollution, while those accounting for 42.1-46.5% and 41.2 +1.3%, respectively, in O-3- and PM2.5-single pollution, which further confirmed the relatively stronger atmospheric chemistry processes in co-pollution. And the high proportion of SIA in co-pollution was mainly attributed to SO42-, which was observed to rapidly boom in non-refractory submicron aerosol (NR-PM1) on the condition of high level of O-3 at daytime. Additionally, we further explored the interactions of O-3 and PM2.5 in co-pollution. It was found that most (similar to 61.9%) co-pollution episodes were initiated by high O-3 at daytime; while for other episodes, high PM2.5 firstly occurred under the more stable meteorological conditions, and then accumulation of precursors further induced high O-3. A higher SIA concentration was observed in O-3-initiated co-pollution, indicating that the atmospheric oxidation in co-pollution caused by chemical processes was stronger than that by physical processes, which was further approved by the higher values of SOR and NOR in O-3-initiated co-pollution. This observational study revealed that controlling O-3 and precursor SO2 is the key to abating co-pollution in the hot season.
Keyword ：
Precursors Precursors Co-pollution Co-pollution High level of oxidation products High level of oxidation products Meteorology Meteorology Surface O-3 and PM2.5 Surface O-3 and PM2.5
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| GB/T 7714 | Ou, Shengju , Wei, Wei , Cai, Bin et al. Exploring the causes for co-pollution of O-3 and PM2.5 in summer over North China [J]. | ENVIRONMENTAL MONITORING AND ASSESSMENT , 2022 , 194 (4) . |
| MLA | Ou, Shengju et al. "Exploring the causes for co-pollution of O-3 and PM2.5 in summer over North China" . | ENVIRONMENTAL MONITORING AND ASSESSMENT 194 . 4 (2022) . |
| APA | Ou, Shengju , Wei, Wei , Cai, Bin , Yao, Shiyin , Wang, Kai , Cheng, Shuiyuan . Exploring the causes for co-pollution of O-3 and PM2.5 in summer over North China . | ENVIRONMENTAL MONITORING AND ASSESSMENT , 2022 , 194 (4) . |
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Currently, the characteristics of volatile organic compounds (VOC) released from coking industry are still vague, and the widely used VOC emission factors (EFs) were still from the measurements of 1990s. Hence, focusing on coking industry, we conducted an in-situ measurement campaign in several typical plants, developed a set of VOC EFs for various release units, and estimated the current emission amounts and future reduction potentials of VOC in China. The measurements show that the levels of VOC in stationary units were 63.82–9563.93 μg·m−3, and those surrounding fugitive units were 111.37–1436.36 μg·m−3. VOC emissions from stationary units were directly calculated, which deducing EFs of 11.57, 15.51, 127.13, 0.28, 0.16 g·t−1 coke respectively for coke charging, coke pushing, coke oven chimney, dry quenching, and wastewater treatment processes. Meanwhile, VOC emissions from fugitive units were simulated following the inverse dispersion method, which achieving EFs of 443.34 ± 66.31, 352.12 ± 65.81, and 718.56 ± 132.69 g·t−1 coke respectively for the coke oven leakage, byproduct recovery with VOC treatment system, and byproduct recovery without VOC treatment system. Generally, the coking plants installing VOC treatment system had total VOC EF of 953.76 g·t−1 coke, about 37.1% lower than those never considering VOC treatment (1516.25 g·t−1 coke). According to these developed EFs, the VOC emission amount from coking industry in China were estimated, slightly decreasing from 623.54 to 578.17 Gg per year, although the coke production increasing from 410.86 to 418.26 Tg during 2015–2019. In future, according to the national industrial policies, regulations and standards, technical guidelines, the VOC reduction potential of this industry in China could reach 336.9 Gg, to which headstream adjustment, process improvement, and end-of-pipe control contributed about 21.4%, 31.6%, and 47.0%, respectively. © 2022 Elsevier B.V.
Keyword ：
Coking industry; Emission factors; Emission reduction potential; Volatile organic compounds Coking industry; Emission factors; Emission reduction potential; Volatile organic compounds
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| GB/T 7714 | Cheng, L. , Wei, W. , Zhang, C. et al. Quantitation study on VOC emissions and their reduction potential for coking industry in China: Based on in-situ measurements on treated and untreated plants [J]. | Science of the Total Environment , 2022 , 836 . |
| MLA | Cheng, L. et al. "Quantitation study on VOC emissions and their reduction potential for coking industry in China: Based on in-situ measurements on treated and untreated plants" . | Science of the Total Environment 836 (2022) . |
| APA | Cheng, L. , Wei, W. , Zhang, C. , Xu, X. , Sha, K. , Meng, Q. et al. Quantitation study on VOC emissions and their reduction potential for coking industry in China: Based on in-situ measurements on treated and untreated plants . | Science of the Total Environment , 2022 , 836 . |
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Abstract ：
Beijing has achieved significant air quality improvement over the past decade. In this study, we applied a simulation technique on pollutant monitoring data to investigate the contribution of emission reduction (ERE) and meteorological effects (ME) to the improvement of air quality. We measured the daily PM2.5 concentrations during four months (representing the four seasons) in 2013 and 2018. We found that the concentrations of NH4+, NO3, and SO42- decreased from 2013 to 2018, but the proportion of NO3 in PM2.5 showed an apparent increase. Multiple scenarios were simulated using the WRF-CAMx model to determine the impact of ERE and ME on air pollution. The results showed that both variables positively contributed to the annual air quality improvement, with ERE contributing more than 70% to the total PM2.5 reduction. However, their seasonal contributions showed notable differences. In winter, ME contributed more than 40 mu g/m(3) to the PM2.5 decrease, which was much higher than that in other seasons. This suggests that the positive effect of pollutant emission reduction on air quality may have been weakened under extremely adverse meteorological conditions. Hence, the monitoring and modeling results were coupled to evaluate the secondary conversion degree. We found that the emissions of precursors, including SO2 and NOx, notably decreased, but both the local and regional conversion degrees increased from 2013 to 2018. Therefore, for effective air pollution reduction, we suggest that future air pollution mitigation measures should focus on reducing secondary pollution in Beijing.
Keyword ：
Secondary conversion degree Secondary conversion degree Emission reduction effect Emission reduction effect Meteorological effect Meteorological effect Air quality improvement Air quality improvement
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| GB/T 7714 | Wang, Xiaoqi , Wei, Wei , Cheng, Shuiyuan et al. Evaluation of continuous emission reduction effect on PM2.5 pollution improvement through 2013-2018 in Beijing [J]. | ATMOSPHERIC POLLUTION RESEARCH , 2021 , 12 (5) . |
| MLA | Wang, Xiaoqi et al. "Evaluation of continuous emission reduction effect on PM2.5 pollution improvement through 2013-2018 in Beijing" . | ATMOSPHERIC POLLUTION RESEARCH 12 . 5 (2021) . |
| APA | Wang, Xiaoqi , Wei, Wei , Cheng, Shuiyuan , Wang, Ruipeng , Zhu, Jiaxian . Evaluation of continuous emission reduction effect on PM2.5 pollution improvement through 2013-2018 in Beijing . | ATMOSPHERIC POLLUTION RESEARCH , 2021 , 12 (5) . |
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Abstract ：
This study conducted a VOCs monitoring campaign in Jul and Oct of 2018, Jan and Apr of 2019 in Beijing urban area, to explore the atmospheric oxidation capacity and its impact on PM2.5 there through investigating the chemical behaviors of VOCs at a 1-h time resolution. We totally detected 53 VOCs in the atmosphere over Beijing, sum of them (TVOCs) reaching 29.0 ± 12.9, 47.6 ± 29.4, 45.7 ± 56.4 and 35.8 ± 19.3 ppb (mol/mol) in Jul, Oct, Jan and Apr respectively. The gap between VOCs and CO diurnal amplitudes presented the trend of Jul > Oct and Apr > Jan, which implies the more chemical loss of VOCs in non-winter seasons compared to winter. Then, according to the notable difference in OH- and O3- reactivity of various VOCs, hourly OH exposure ([OH]Δt), O3 exposure ([O3]Δt) and OH concentration were estimated. In result, in Jul, Oct, Jan and Apr, the daily [OH]Δt was 10.39 ± 4.95, 11.10 ± 6.01, 6.39 ± 3.74 and 8.96 ± 5.05 × 1010 molecules·s·cm−3, the nighttime [O3]Δt was 9.43 ± 2.83, 5.22 ± 3.62, 5.79 ± 3.65 and 8.60 ± 4.74 × 1015 molecules·s·cm−3, and the daily OH was 9.76 ± 5.17, 5.11 ± 2.98, 2.95 ± 2.18 and 6.26 ± 3.18 × 106 molecules·cm−3, in respective. The OH peak magnitudes agreed well with the OH measured in-site, which indicates the reliability of our estimates on the oxidation capacity of atmosphere over Beijing. During our studied periods, [OH]Δt, OH and atmospheric oxidability combining OH and O3 (ACO) were all positively related to PM2.5 in Jul and Apr; only [OH]Δt was positively related to PM2.5 in Oct; while [OH]Δt, OH and ACO were all negatively related to PM2.5 in Jan. The proportion of SO2 and VOCs oxidized through gaseous OH reactions was found to increase with PM2.5 increasing in non-winter seasons, but decrease with PM2.5 increasing in winter. It means that high PM2.5 concentrations are attributed more to gas-phase oxidations in non-winter seasons and potentially boosted by photochemistry in summer and spring. But, in winter high PM2.5 concentrations effectively inhibit photolysis reactions and weaken atmospheric oxidation capacity, which makes high PM2.5 less dependent on the gas-phase oxidations. © 2021 Elsevier B.V.
Keyword ：
Volatile organic compounds Volatile organic compounds Gas chromatography Gas chromatography Free radicals Free radicals Oxidation Oxidation Molecules Molecules Atmospheric chemistry Atmospheric chemistry
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| GB/T 7714 | Wei, Wei , Wang, Yue , Bai, Hongxiang et al. Insights into atmospheric oxidation capacity and its impact on PM2.5 in megacity Beijing via volatile organic compounds measurements [J]. | Atmospheric Research , 2021 , 258 . |
| MLA | Wei, Wei et al. "Insights into atmospheric oxidation capacity and its impact on PM2.5 in megacity Beijing via volatile organic compounds measurements" . | Atmospheric Research 258 (2021) . |
| APA | Wei, Wei , Wang, Yue , Bai, Hongxiang , Wang, Xiaoqi , Cheng, Shuiyuan , Wang, Litao . Insights into atmospheric oxidation capacity and its impact on PM2.5 in megacity Beijing via volatile organic compounds measurements . | Atmospheric Research , 2021 , 258 . |
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