1
|
Lee HM, Kim NK, Ahn J, Park SM, Lee JY, Kim YP. When and why PM 2.5 is high in Seoul, South Korea: Interpreting long-term (2015-2021) ground observations using machine learning and a chemical transport model. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 920:170822. [PMID: 38365024 DOI: 10.1016/j.scitotenv.2024.170822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 01/12/2024] [Accepted: 02/06/2024] [Indexed: 02/18/2024]
Abstract
Seoul has high PM2.5 concentrations and has not attained the national annual average standard so far. To understand the reasons, we analyzed long-term (2015-2021) hourly observations of aerosols (PM2.5, NO3-, NH4+, SO42-, OC, and EC) and gases (CO, NO2, and SO2) from Seoul and Baekryeong Island, a background site in the upwind region of Seoul. We applied the weather normalization method for meteorological conditions and a 3-dimensional chemical transport model, GEOS-Chem, to identify the effect of policy implementation and aerosol formation mechanisms. The monthly mean PM2.5 ranges between about 20 μg m-3 (warm season) and about 40 μg m-3 (cold season) at both sites, but the annual decreasing rates were larger at Seoul than at Baengnyeong (-0.7 μg m-3 a-1 vs. -1.8 μg m-3 a-1) demonstrating the effectiveness of the local air quality policies including the Special Act on Air Quality in the Seoul Metropolitan Area (SAAQ-SMA) and the seasonal control measures. The weather-normalized monthly mean data shows the highest PM2.5 concentration in March and the lowest concentration in August throughout the 7 years with NO3- accounting for about 40 % of the difference between the two months at both sites. Taking together with the GEOS-Chem model results, which reproduced the elevated NO3- in March, we concluded the elevated atmospheric oxidant level increases in HNO3 (which is not available from the observation) and the still low temperatures in March promote rapid production of NO3-. We used Ox (≡ O3 + NO2) from the observation and OH from the GEOS-Chem as a proxy for the atmospheric oxidant level which can be a source of uncertainty. Thus, direct observations of OH and HNO3 are needed to provide convincing evidence. This study shows that reducing HNO3 levels through atmospheric oxidant level control in the cold season can be effective in PM2.5 mitigation in Seoul.
Collapse
Affiliation(s)
- Hyung-Min Lee
- Department of Environmental Science and Engineering, Ewha Womans University, Seoul, South Korea.
| | - Na Kyung Kim
- Department of Environmental Science and Engineering, Ewha Womans University, Seoul, South Korea
| | - Joonyoung Ahn
- Air Quality Research Division, National Institute of Environmental Research, Incheon, South Korea
| | - Seung-Myung Park
- Air Quality Research Division, National Institute of Environmental Research, Incheon, South Korea
| | - Ji Yi Lee
- Department of Environmental Science and Engineering, Ewha Womans University, Seoul, South Korea
| | - Yong Pyo Kim
- Department of Chemical Engineering and Materials Science, Ewha Womans University, Seoul, South Korea
| |
Collapse
|
2
|
Shi R, Zhang F, Shen Y, Shen J, Xu B, Kuang B, Xu Z, Jin L, Tang Q, Tian X, Wang Z. Aerosol liquid water in PM 2.5 and its roles in secondary aerosol formation at a regional site of Yangtze River Delta. J Environ Sci (China) 2024; 138:684-696. [PMID: 38135431 DOI: 10.1016/j.jes.2023.04.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 04/22/2023] [Accepted: 04/22/2023] [Indexed: 12/24/2023]
Abstract
Aerosol liquid water content (ALWC) plays an important role in secondary aerosol formation. In this study, a whole year field campaign was conducted at Shanxi in north Zhejiang Province during 2021. ALWC estimated by ISORROPIA-II was then investigated to explore its characteristics and relationship with secondary aerosols. ALWC exhibited a highest value in spring (66.38 µg/m3), followed by winter (45.08 µg/m3), summer (41.64 µg/m3), and autumn (35.01 µg/m3), respectively. It was supposed that the secondary inorganic aerosols (SIA) were facilitated under higher ALWC conditions (RH > 80%), while the secondary organic species tended to form under lower ALWC levels. Higher RH (> 80%) promoted the NO3- formation via gas-particle partitioning, while SO42- was generated at a relative lower RH (> 50%). The ALWC was more sensitive to NO3- (R = 0.94) than SO42- (R = 0.90). Thus, the self-amplifying processes between the ALWC and SIA enhanced the particle mass growth. The sensitivity of ALWC and OX (NO2 + O3) to secondary organic carbon (SOC) varied in different seasons at Shanxi, more sensitive to aqueous-phase reactions (daytime R = 0.84; nighttime R = 0.54) than photochemical oxidation (daytime R = 0.23; nighttime R = 0.41) in wintertime with a high level of OX (daytime: 130-140 µg/m3; nighttime: 100-140 µg/m3). The self-amplifying process of ALWC and SIA and the aqueous-phase formation of SOC will enhance aerosol formation, contributing to air pollution and reduction of visibility.
Collapse
Affiliation(s)
- Ruifang Shi
- College of Environmental and Resource Sciences, Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China
| | - Fei Zhang
- College of Environmental and Resource Sciences, Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China
| | - Yemin Shen
- Zhejiang Ecological and Environmental Monitoring Center, Hangzhou 310012, China
| | - Jiasi Shen
- Zhejiang Ecological and Environmental Monitoring Center, Hangzhou 310012, China
| | - Bingye Xu
- Zhejiang Ecological and Environmental Monitoring Center, Hangzhou 310012, China
| | - Binyu Kuang
- College of Environmental and Resource Sciences, Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China
| | - Zhengning Xu
- College of Environmental and Resource Sciences, Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China
| | - Lingling Jin
- Zhejiang Ecological and Environmental Monitoring Center, Hangzhou 310012, China
| | - Qian Tang
- Zhejiang Ecological and Environmental Monitoring Center, Hangzhou 310012, China
| | - Xudong Tian
- Zhejiang Ecological and Environmental Monitoring Center, Hangzhou 310012, China
| | - Zhibin Wang
- College of Environmental and Resource Sciences, Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China; ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311215, China.
| |
Collapse
|
3
|
Yang J, Qu Y, Chen Y, Zhang J, Liu X, Niu H, An J. Dominant physical and chemical processes impacting nitrate in Shandong of the North China Plain during winter haze events. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169065. [PMID: 38065496 DOI: 10.1016/j.scitotenv.2023.169065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/14/2023] [Accepted: 12/01/2023] [Indexed: 01/18/2024]
Abstract
Nitrate has been a dominant component of PM2.5 since the stringent emission control measures implemented in China in 2013. Clarifying key physical and chemical processes influencing nitrate concentrations is crucial for eradicating heavy air pollution in China. In this study, we explored dominant processes impacting nitrate concentrations in Shandong of the North China Plain during three haze events from 9 to 25 December 2021, named cases P1 (94.46 (30.85) μg m-3 for PM2.5 (nitrate)), P2 (148.95 (50.12) μg m-3) and P3 (88.03 (29.21) μg m-3), by using the Weather Research and Forecasting/Chemistry model with an integrated process rate analysis scheme and updated heterogeneous hydrolysis of dinitrogen pentoxide on the wet aerosol surface (HET-N2O5) and additional nitrous acid (HONO) sources (AS-HONO). The results showed that nitrate increases in the three cases were attributed to aerosol chemistry, whereas nitrate decreases were due mainly to the vertical mixing process in cases P1 and P2 and to the advection process in case P3. HET-N2O5 (the reaction of OH + NO2) contributed 45 % (51 %) of the HNO3 production rate during the study period. AS-HONO produced a nitrate enhancement of 24 % in case P1, 12 % in case P2 and 19 % in case P3, and a HNO3 production rate enhancement of 0.79- 0.97 (0.18- 0.60) μg m-3 h-1 through the reaction of OH + NO2 (HET-N2O5) in the three cases. This study implies that using suitable parameterization schemes for heterogeneous reactions on aerosol and ground surfaces and nitrate photolysis is vital in simulations of HONO and nitrate, and the MOSAIC module for aerosol water simulations needs to be improved.
Collapse
Affiliation(s)
- Juan Yang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu Qu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Yong Chen
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jingwei Zhang
- Department of Atmospheric Sciences, Yunnan University, Kunming 650091, China
| | - Xingang Liu
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Hongya Niu
- School of Earth Sciences and Engineering, Hebei University of Engineering, Handan 056038, China
| | - Junling An
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| |
Collapse
|
4
|
Zhang Y, Wang H, Huang L, Qiao L, Zhou M, Mu J, Wu C, Zhu Y, Shen H, Huang C, Wang G, Wang T, Wang W, Xue L. Double-Edged Role of VOCs Reduction in Nitrate Formation: Insights from Observations during the China International Import Expo 2018. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:15979-15989. [PMID: 37821356 DOI: 10.1021/acs.est.3c04629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Aerosol nitrate (NO3-) constitutes a significant component of fine particles in China. Prioritizing the control of volatile organic compounds (VOCs) is a crucial step toward achieving clean air, yet its impact on NO3- pollution remains inadequately understood. Here, we examined the role of VOCs in NO3- formation by combining comprehensive field measurements conducted during the China International Import Expo (CIIE) in Shanghai (from 10 October to 22 November 2018) and multiphase chemical modeling. Despite a decline in primary pollutants during the CIIE, NO3- levels increased compared to pre-CIIE and post-CIIE─NO3- concentrations decreased in the daytime (by -10 and -26%) while increasing in the nighttime (by 8 and 30%). Analysis of the observations and backward trajectory indicates that the diurnal variation in NO3- was mainly attributed to local chemistry rather than meteorological conditions. Decreasing VOCs lowered the daytime NO3- production by reducing the hydroxyl radical level, whereas the greater VOCs reduction at night than that in the daytime increased the nitrate radical level, thereby promoting the nocturnal NO3- production. These results reveal the double-edged role of VOCs in NO3- formation, underscoring the need for transferring large VOC-emitting enterprises from the daytime to the nighttime, which should be considered in formulating corresponding policies.
Collapse
Affiliation(s)
- Yingnan Zhang
- Environment Research Institute, Shandong University, 250100 Ji'nan, China
- State Environmental Protection Key Laboratory of the Cause and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, 200233 Shanghai, China
| | - Hongli Wang
- State Environmental Protection Key Laboratory of the Cause and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, 200233 Shanghai, China
| | - Liubin Huang
- Environment Research Institute, Shandong University, 250100 Ji'nan, China
| | - Liping Qiao
- State Environmental Protection Key Laboratory of the Cause and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, 200233 Shanghai, China
| | - Min Zhou
- State Environmental Protection Key Laboratory of the Cause and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, 200233 Shanghai, China
| | - Jiangshan Mu
- Environment Research Institute, Shandong University, 250100 Ji'nan, China
| | - Can Wu
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, 200241 Shanghai, China
| | - Yujiao Zhu
- Environment Research Institute, Shandong University, 250100 Ji'nan, China
- State Environmental Protection Key Laboratory of the Cause and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, 200233 Shanghai, China
| | - Hengqing Shen
- Environment Research Institute, Shandong University, 250100 Ji'nan, China
| | - Cheng Huang
- State Environmental Protection Key Laboratory of the Cause and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, 200233 Shanghai, China
| | - Gehui Wang
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, 200241 Shanghai, China
| | - Tao Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, 999077 Hong Kong, China
| | - Wenxing Wang
- Environment Research Institute, Shandong University, 250100 Ji'nan, China
| | - Likun Xue
- Environment Research Institute, Shandong University, 250100 Ji'nan, China
| |
Collapse
|
5
|
Li Y, Han Y, Ma S, Zhang Y, Wang H, Yang J, Yao L, Bi X, Wu J, Feng Y. Comparative analysis of nitrate evolution patterns during pollution episodes: Method development and results from Tianjin, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159436. [PMID: 36302427 DOI: 10.1016/j.scitotenv.2022.159436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 09/29/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023]
Abstract
Particulate nitrate plays an increasingly important role in the formation of air pollution process, while the main mechanisms of nitrate concentration change are different in each stage, same as the driving factors. In this study, we proposed an episode-based analysis to illustrate the typical nitrate evolution patterns and identify the possible impacting factors in different evolution stages. Applying into twelve air pollution episodes, three typical patterns of nitrate evolution were abstracted, and the corresponding conceptual models were constructed. All the pollution episodes were grouped by their evolving shapes, which were driven by physical and chemical processes. Episodes started slowly typically arose from gradual pollutant accumulation, both locally and regionally, and chemical formation under high humidity. Type 1 ("hump-shaped type"), accounting for 66.3 % of the total episode durations, including two "peak" concentrations, displays a rapid growth rate which could up to 4.6 μg m-3 h-1 in average, mainly relying on the sharp drop in the planetary boundary layer height. Short scavenging processes and thoroughly dissipated stages of the pollution episodes always accompanied by strong north wind affected by Siberia-Mongolia cold current. Type 2 ("triangle-shaped type", 24.3 %) shows a gentle growth rate and short duration. Compared with Type 1, chemical process may be more important "source" for the increase of nitrate concentration during Type 2. Type 3 ("trapezoid-shaped type", 9.4 %) presents a long platform stage, during which high humidity (RH > 90 %) provides favorable conditions for wet removal and secondary production, and the updraft can carry pollutants to high altitude. The source and sink are roughly balanced for Type 3. Our study highlights the importance of pattern identification for understanding the nitrate evolution behavior, it may also provide insights for pollution prediction and scientific mitigation strategies.
Collapse
Affiliation(s)
- Yafei Li
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control & Center for Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; CMA-NKU Cooperative Laboratory for Atmospheric Environment-Health Research, Tianjin 300000, China
| | - Yan Han
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Simeng Ma
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control & Center for Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; CMA-NKU Cooperative Laboratory for Atmospheric Environment-Health Research, Tianjin 300000, China
| | - Yufen Zhang
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control & Center for Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; CMA-NKU Cooperative Laboratory for Atmospheric Environment-Health Research, Tianjin 300000, China.
| | - Haoqi Wang
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control & Center for Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; CMA-NKU Cooperative Laboratory for Atmospheric Environment-Health Research, Tianjin 300000, China
| | - Jingyi Yang
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control & Center for Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; CMA-NKU Cooperative Laboratory for Atmospheric Environment-Health Research, Tianjin 300000, China
| | - Lu Yao
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control & Center for Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; CMA-NKU Cooperative Laboratory for Atmospheric Environment-Health Research, Tianjin 300000, China
| | - Xiaohui Bi
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control & Center for Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; CMA-NKU Cooperative Laboratory for Atmospheric Environment-Health Research, Tianjin 300000, China
| | - Jianhui Wu
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control & Center for Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; CMA-NKU Cooperative Laboratory for Atmospheric Environment-Health Research, Tianjin 300000, China
| | - Yinchang Feng
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control & Center for Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; CMA-NKU Cooperative Laboratory for Atmospheric Environment-Health Research, Tianjin 300000, China.
| |
Collapse
|
6
|
Tao J, Huang J, Bian G, Zhang L, Zhou Z, Zhang Z, Li J, Miao Y, Yuan Z, Sha Q, Xiao L, Wang B. Fine particulate pollution driven by nitrate in the moisture urban atmospheric environment in the Pearl River Delta region of south China. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 326:116704. [PMID: 36356536 DOI: 10.1016/j.jenvman.2022.116704] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/17/2022] [Accepted: 11/01/2022] [Indexed: 06/16/2023]
Abstract
To identify potential sources of fine particles (PM2.5, with aerodynamic diameter (Da) ≤ 2.5 μm) in urban Dongguan of south China, a comprehensive campaign was carried out in the whole 2019. Hourly PM2.5 and its dominant chemical components including organic carbon (OC), elemental carbon (EC), water-soluble inorganic ions (WSIIs) and thirteen elements were measured using online instruments. Gaseous pollutants including NH3, HNO3, NO2, NO and O3 and meteorological parameters were also synchronously measured. PM2.5 was dominated by carbonaceous aerosols in summer and by WSIIs in the other seasons. PM2.5 and its dominant chemical components mostly peaked around noon (10:00-14:00 LST). Furthermore, high PM2.5 levels during the daytime were closely related with the increased NO3- levels. The high mass concentrations of NO3- in urban Dongguan during the daytime were likely related with regional transport of NO3- from suburban Dongguan, which was originated from the reaction between NO2 and O3 under the moisture condition during the nighttime. Seven major source factors for PM2.5 including secondary sulfate, ship emission, traffic emission, secondary nitrate, industrial processes, soil dust and coal combustion were identified by positive matrix factorization (PMF) analysis, which contributed 26 ± 14%, 16 ± 16%, 16 ± 10%, 14 ± 11%, 12 ± 11%, 8 ± 6% and 8 ± 6%, respectively, to annual PM2.5 mass concentration. Although secondary sulfate contributed much more than secondary nitrate to PM2.5 on annual basis, the latter exceeded the former source factor when daily PM2.5 mass concentration was higher than 60 μg m-3, indicating the critical role nitrate played in PM2.5 episode events.
Collapse
Affiliation(s)
- Jun Tao
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China; South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, China.
| | - Junjun Huang
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China
| | - Guojian Bian
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, China
| | - Leiming Zhang
- Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, Canada
| | - Zhen Zhou
- Dongguan Sub-branch of Guangdong Ecological and Environmental Monitoring Center, Dongguan, China
| | - Zhisheng Zhang
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, China
| | - Jiawei Li
- RCE-TEA, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
| | - Yucong Miao
- Chinese Academy of Meteorological Sciences, Beijing, China
| | - Ziyang Yuan
- Sailbri Cooper Inc., Tigard, Oregon, United States
| | - Qinge Sha
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China
| | - Linhai Xiao
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China
| | - Boguang Wang
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China
| |
Collapse
|
7
|
Wang F, Lv S, Liu X, Lei Y, Wu C, Chen Y, Zhang F, Wang G. Investigation into the differences and relationships between gasSOA and aqSOA in winter haze pollution on Chongming Island, Shanghai, based on VOCs observation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 316:120684. [PMID: 36400138 DOI: 10.1016/j.envpol.2022.120684] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/08/2022] [Accepted: 11/14/2022] [Indexed: 06/16/2023]
Abstract
To investigate the formation of secondary organic aerosol (SOA) under current atmospheric conditions, we conducted a field observation of SOA precursors in the downwind region of the Yangtze River Delta (YRD) in winter 2019 using a variety of offline and online instruments. During the entire observation period, the averaged fine particulate SOA was 7.9 ± 2.3 μg m-3, with precursor concentrations of 31 ± 11 ppbv for the measured volatile organic compounds (VOCs) and 16 ± 12 ppbv for NOx. Compared to those on the clean days, SOA on the haze days increased by a factor of 1.6, while the VOC and NOx increased by a factor of 1.3 and 2.0, respectively. Aerosol liquid water content (ALWC) and oxygenated VOCs (OVOCs, including acetaldehyde, formic acid, acetone, acetic acid, methyl ethyl ketone, and methylglyoxal) relationships suggested that the gasSOA and aqSOA occurred simultaneously on Chongming Island in winter. The gasSOA was primarily formed by the oxidation of aromatics and NOx at low RH (RH < 80%) conditions. In contrast, the aqSOA was formed under higher RH (RH > 80%) conditions via a combination of daytime photochemical aqueous phase processes of water-soluble OVOCs and nocturnal dark aqueous phase processes of primary emissions from biomass. The inversed higher mass ratio of NACs to (benzene + toluene) and nitrogen oxidation ratio (NOR) in the daytime during the gasSOA-dominated haze periods indicated that gasSOA could be transformed to aqSOA at high NOx levels. Our results also suggested the importance of NOx and VOC reduction measures in directly mitigating gasSOA and indirectly mitigating aqSOA during winter haze pollution.
Collapse
Affiliation(s)
- Fanglin Wang
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200062, China
| | - Shaojun Lv
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200062, China
| | - Xiaodi Liu
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200062, China
| | - Yali Lei
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200062, China
| | - Can Wu
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200062, China
| | - Yubao Chen
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200062, China
| | - Fan Zhang
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200062, China
| | - Gehui Wang
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200062, China; Institute of Eco-Chongming, Chenjia Zhen, Chongming, Shanghai, 202162, China.
| |
Collapse
|
8
|
Xie X, Hu J, Qin M, Guo S, Hu M, Wang H, Lou S, Li J, Sun J, Li X, Sheng L, Zhu J, Chen G, Yin J, Fu W, Huang C, Zhang Y. Modeling particulate nitrate in China: Current findings and future directions. ENVIRONMENT INTERNATIONAL 2022; 166:107369. [PMID: 35772313 DOI: 10.1016/j.envint.2022.107369] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 06/07/2022] [Accepted: 06/20/2022] [Indexed: 06/15/2023]
Abstract
Particulate nitrate (pNO3) is now becoming the principal component of PM2.5 during severe winter haze episodes in many cities of China. To gain a comprehensive understanding of the key factors controlling pNO3 formation and driving its trends, we reviewed the recent pNO3 modeling studies which mainly focused on the formation mechanism and recent trends of pNO3 as well as its responses to emission controls in China. The results indicate that although recent chemical transport models (CTMs) can reasonably capture the spatial-temporal variations of pNO3, model-observation biases still exist due to large uncertainties in the parameterization of dinitrogen pentoxide (N2O5) uptake and ammonia (NH3) emissions, insufficient heterogeneous reaction mechanism, and the predicted low sulfate concentrations in current CTMs. The heterogeneous hydrolysis of N2O5 dominates nocturnal pNO3 formation, however, the contribution to total pNO3 varies among studies, ranging from 21.0% to 51.6%. Moreover, the continuously increasing PM2.5 pNO3 fraction in recent years is mainly due to the decreased sulfur dioxide emissions, the enhanced atmospheric oxidation capacity (AOC), and the weakened nitrate deposition. Reducing NH3 emissions is found to be the most effective control strategy for mitigating pNO3 pollution in China. This review suggests that more field measurements are needed to constrain the parameterization of heterogeneous N2O5 and nitrogen dioxide (NO2) uptake. Future studies are also needed to quantify the relationships of pNO3 to AOC, O3, NOx, and volatile organic compounds (VOCs) in different regions of China under different meteorological conditions. Research on multiple-pollutant control strategies involving NH3, NOX, and VOCs is required to mitigate pNO3 pollution, especially during severe winter haze events.
Collapse
Affiliation(s)
- Xiaodong Xie
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Jianlin Hu
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China.
| | - Momei Qin
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Song Guo
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Min Hu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Hongli Wang
- State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, China
| | - Shengrong Lou
- State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, China
| | - Jingyi Li
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Jinjin Sun
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Xun Li
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Li Sheng
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Jianlan Zhu
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Ganyu Chen
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Junjie Yin
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Wenxing Fu
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Cheng Huang
- State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, China
| | - Yuanhang Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; CAS Center for Excellence in Regional Atmospheric Environment, Chinese Academy of Science, Xiamen 361021, China.
| |
Collapse
|
9
|
Li Z, Walters WW, Hastings MG, Song L, Huang S, Zhu F, Liu D, Shi G, Li Y, Fang Y. Atmospheric nitrate formation pathways in urban and rural atmosphere of Northeast China: Implications for complicated anthropogenic effects. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 296:118752. [PMID: 34968617 DOI: 10.1016/j.envpol.2021.118752] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 12/14/2021] [Accepted: 12/23/2021] [Indexed: 06/14/2023]
Abstract
Effects of human activities on atmospheric nitrate (NO3-) formation remain unclear, though the knowledge is critical for improving atmospheric chemistry models and nitrogen deposition reduction strategies. A potentially useful way to explore this is to compare NO3- oxidation processes in urban and rural atmospheres based upon the oxygen stable isotope composition of NO3- (Δ17O-NO3-). Here we compared the Δ17O-NO3- from three-years of daily-based bulk deposition in urban (Shenyang) and forested rural sites (Qingyuan) in northeast China and quantified the relative contributions of different formation pathways based on the SIAR model. Our results showed that the Δ17O in Qiangyuan (26.2 ± 3.3‰) is significantly higher (p < 0.001) than in Shenyang (24.0 ± 4.0‰), and significantly higher in winter (Shenyang: 26.1 ± 6.7‰, Qingyuan: 29.6 ± 2.5‰) than in summer (Shenyang: 22.7 ± 2.9‰, Qingyuan: 23.8 ± 2.4‰) in both sites. The lower values in the urban site are linked with conditions that favored a higher relative contribution of nitrogen dioxide reaction with OH pathway (0.76-0.91) than in rural site (0.47-0.62), which should be induced by different levels of human activities in the two sites. The seasonal variations of Δ17O-NO3- in both sites are explained by a higher relative contribution of ozone-mediated oxidation chemistry and unfavorable conditions for the OH pathway during winter relative to summer, which is affected by human activities and seasonal meteorological condition change. Based on Δ17O, wintertime conditions led to a contribution of O3 related pathways (NO3 + DMS/HC and N2O5 hydrolysis) of 0.63 in Qingyuan and 0.42 in Shenyang, while summertime conditions led to 0.15 in Qingyuan and 0.05 in Shenyang. Our comparative study on Δ17O-NO3- between urban and rural sites reveals different anthropogenic effects on nitrate formation processes on spatial and temporal scales, illustrating different responses of reactive nitrogen chemistry to changes in human activities.
Collapse
Affiliation(s)
- Zhengjie Li
- National Engineering Laboratory for Applied Technology of Forestry & Ecology in Southern China, College of Biological Science and Technology, Central South University of Forestry and Technology, Changsha, Hunan, 410004, China; CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning, 110016, China
| | - Wendell W Walters
- Institute at Brown for Environment and Society, Brown University, Providence, RI, 02912, USA
| | - Meredith G Hastings
- Institute at Brown for Environment and Society, Brown University, Providence, RI, 02912, USA; Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI, 02912, USA
| | - Linlin Song
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning, 110016, China; Key Laboratory of Stable Isotope Techniques and Applications, Liaoning Province, 110016, China
| | - Shaonan Huang
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Geography and Environment Science, Henan University, Kaifeng, 475004, China
| | - Feifei Zhu
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning, 110016, China; Qingyuan Forest CERN, Chinese Academy of Sciences, Shenyang, Liaoning, 110016, China; Key Laboratory of Stable Isotope Techniques and Applications, Liaoning Province, 110016, China
| | - Dongwei Liu
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning, 110016, China; Qingyuan Forest CERN, Chinese Academy of Sciences, Shenyang, Liaoning, 110016, China; Key Laboratory of Stable Isotope Techniques and Applications, Liaoning Province, 110016, China
| | - Guitao Shi
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, Shanghai, 200241, China
| | - Yilan Li
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, Shanghai, 200241, China
| | - Yunting Fang
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning, 110016, China; Qingyuan Forest CERN, Chinese Academy of Sciences, Shenyang, Liaoning, 110016, China; Key Laboratory of Stable Isotope Techniques and Applications, Liaoning Province, 110016, China.
| |
Collapse
|
10
|
Chen Z, Tian Z, Liu X, Sun W. The potential risks and exposure of Qinling giant pandas to polycyclic aromatic hydrocarbon (PAH) pollution. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 292:118294. [PMID: 34626712 DOI: 10.1016/j.envpol.2021.118294] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 09/28/2021] [Accepted: 10/04/2021] [Indexed: 06/13/2023]
Abstract
Rapid industrialization and urbanization have created a substantial urban-rural gradient for various pollutants. The Qinling Mountains are highly important in terms of biodiversity, providing habitat for giant pandas, which are endemic to China and are a widely recognized symbol for conservation. Whether polycyclic aromatic hydrocarbon (PAH) exposure risks regarding in situ animal conservation zones are affected by environmental pollution or even enhanced by the mountain-trapping effect requires further research. Our group carried out a large-scale investigation on the area ranging from Xi'an to Hanzhong across the giant panda habitat in the Qinling Mountains by collecting atmosphere, soil, bamboo, and fecal samples from different sites over a two-year period. The total toxicity of atmospheric PAHs and the frequencies of soil PAHs above effect range low (ERL) values showed a decreasing trend from urban areas to the central mountains, suggesting a distance effect from the city. The proportions of total 5- and 6-ring PAHs in the atmosphere were higher in the central mountainous areas than in the urban areas, while this difference was reversed in the soil. Health risk assessments showed that the incremental lifetime carcinogenic risks (ILCR) of PAH exposure by bamboo ingestion ranged from 2.16 × 10-4 to 3.11 × 10-4, above the critical level of 10-4. Bamboo ingestion was the main driver of the PAH exposure risks. The concentration difference between bamboo and fecal samples provided a reference for the level of PAHs absorbed by the panda digestive system. Since the Qinling Mountains possess the highest density of giant pandas and provide habitats to many other endangered animal and plant species, we should not ignore the probability of health risks posed by PAHs. Monitoring the pollution level and reducing the atmospheric emissions of toxic pollutants are recommended actions. Further detailed research should also be implemented on pandas' health effects of contaminant exposure.
Collapse
Affiliation(s)
- Zhigang Chen
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, And School of Environment, Tsinghua University, Beijing, 100084, China
| | - Zhaoxue Tian
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, And School of Environment, Tsinghua University, Beijing, 100084, China
| | - Xuehua Liu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, And School of Environment, Tsinghua University, Beijing, 100084, China.
| | - Wanlong Sun
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, And School of Environment, Tsinghua University, Beijing, 100084, China
| |
Collapse
|