Source Contributions to PM2.5 under Unfavorable Weather Conditions in Guangzhou City, China

Wang, Nan; Ling, Zhenhao; Deng, Xuejiao; Deng, Tao; Lyu, Xiaopu; Li, Tingyuan; Gao, Xiaorong; Chen, Xi

doi:10.1007/s00376-018-7212-9

Cited by 20 publications

(11 citation statements)

References 47 publications

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“…Previous studies indicated that meteorological conditions played important roles in the secondary aerosol and O 3 formation. 29 , 30 For example, relatively low wind speed, high temperature, high solar radiation, and low planetary boundary layer height (PBLH) were the favorable meteorological conditions for the formation of secondary pollutants. Our analysis implied that meteorological conditions were more conducive to photochemical formation during the LOCK than during the PRE in Nanjing, but were more unfavorable in Guangzhou.…”

Section: Resultsmentioning

confidence: 99%

Air Quality During COVID-19 Lockdown in the Yangtze River Delta and the Pearl River Delta: Two Different Responsive Mechanisms to Emission Reductions in China

Wang

Pei

et al. 2021

Environ. Sci. Technol.

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Despite the large reduction in anthropogenic activities due to the outbreak of COVID-19, air quality in China has witnessed little improvement and featured great regional disparities. Here, by combining observational data and simulations, this work aims to understand the diverse air quality response in two city clusters, Yangtze River Delta region (YRD) and Pearl River Delta region (PRD), China. Though there was a noticeable drop in primary pollutants in both the regions, differently, the maximum daily 8 h average ozone (O 3 ) soared by 20.6–76.8% in YRD but decreased by 15.5–28.1% in PRD. In YRD, nitrogen oxide (NOx) reductions enhanced O 3 accumulation and hence increased secondary aerosol formation. Such an increment in secondary organic and inorganic aerosols under stationary weather reached up to 36.4 and 10.2%, respectively, which was further intensified by regional transport. PRD was quite the opposite. The emission reductions benefited PRD air quality, while regional transport corresponded to an increase of 17.3 and 9.3% in secondary organic and inorganic aerosols, respectively. Apart from meteorology, the discrepancy in O 3 –VOCs–NOx relationships determined the different O 3 responses, indicating that future emission control shall be regionally specific, instead of one-size-fits-all cut. Overall, the importance of regionally coordinated and balanced control strategy for multiple pollutants is highly emphasized.

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Section: Resultsmentioning

confidence: 99%

Air Quality During COVID-19 Lockdown in the Yangtze River Delta and the Pearl River Delta: Two Different Responsive Mechanisms to Emission Reductions in China

Wang

Pei

et al. 2021

Environ. Sci. Technol.

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“…The detailed configuration of the WRF-CMAQ model was summarized in Table 1. Our previous studies have demonstrated that this configuration of the modelling system could have great performance in the simulation of air quality in the PRD region [35,36]. The 2008-based Multi-resolution Emission Inventory for China (MEIC), developed by Tsinghua University, was used for anthropogenic emissions.…”

Section: Description and Configuration Of Community Multiscale Air Qumentioning

confidence: 99%

“…The detailed configuration of the WRF-CMAQ model was summarized in Table 1. Our previous studies have demonstrated that this configuration of the modelling system could have great performance in the simulation of air quality in the PRD region [35,36]. In this study, measurement data from seven surface meteorological sites and one surface intensive observation site (i.e., the BGS site) were used to validate the simulated results from both WRF and CMAQ modeling systems.…”

Section: Description and Configuration Of Community Multiscale Air Qumentioning

confidence: 99%

PAN–Precursor Relationship and Process Analysis of PAN Variations in the Pearl River Delta Region

et al. 2018

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Peroxy acetyl nitrate (PAN) is an important photochemical product formed from the reactions between volatile organic compounds (VOCs) and nitrogen oxides (NO x ) under sunlight. In this study, a field measurement was conducted at a rural site (the backgarden site, or BGS) of the Pearl River Delta (PRD) region in 2006, with the 10 min maximum PAN mixing ratios of 3.9 ppbv observed. The factors influencing the abundance of PAN at the BGS site was evaluated by the process analysis through the Weather Research and Forecasting-Community Multiscale Air Quality (WRF-CMAQ) model. The results suggested that the increase of PAN abundance at the BGS site was mainly controlled by the gas-phase chemistry, followed by vertical transport, while its loss was modulated mainly by dry deposition and horizontal transport. As the dominant important role of gas-phase chemistry, to provide detailed information on the photochemical formation of PAN, a photochemical box model with near-explicit chemical mechanism (i.e., the master chemical mechanism, MCM) was used to explore the relationship of photochemical PAN formation with its precursors based on the measured data at the BGS site. It was found that PAN formation was VOC-limited at the BGS site, with the oxidation of acetaldehyde the most important pathway for photochemical PAN production, followed by the oxidation and photolysis of methylglyoxal (MGLY). Among all the primary VOC precursors, isoprene and xylenes were the main contributors to PAN formation. Overall, our study provides new insights into the PAN photochemical formation and its controlling factors, and highlighted the importance of gas chemistry on the PAN abundance in the PRD region.Atmosphere 2018, 9, 372 2 of 16 nitrogen oxides (NO x ), PAN could also be formed in air far away from these sources. PAN is relatively stable at low temperatures; however, it can be decomposed when the atmospheric temperature is high [2]. As a NO 2 reservoir species, it reduces NO 2 concentrations near the emission sources but releases NO 2 in regions remote from fresh emission sources [3]. It is, hence, concerning that PAN can affect NO x abundance and, ultimately, influence tropospheric ozone formation on local and regional scales.PAN is formed from the reaction of NO 2 and peroxy acetyl (PA) radical which is produced through photolysis and oxidation of a small number of oxygenated volatile organic compounds (OVOCs) (e.g., acetaldehyde (CH 3 CHO), acetone, methacrolein (MACR), methyl vinyl ketone (MVK), methyl ethyl ketone, and methylglyoxal (MGLY)) initiated by OH, NO 3 , and O 3 . Therefore, the abundances of aforementioned OVOCs will directly impact PAN levels in the atmosphere. Since PAN was first discovered in photochemical smog in Los Angeles in the 1950s, numerous studies have investigated the distribution and source contributions of PAN through field measurements and model simulations [3][4][5][6]. The characterization includes the abundance of PAN, the relationship with its precursors, and the contributions of regional transport i...

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“…Haze pollution in the ambient atmosphere induced by high aerosol concentrations, especially anthropogenic fine particles with aerodynamic diameters less than or equal to 2.5 μm (PM 2.5 ) ( Li et al, 2017 ), has been the most prevalent atmospheric pollution phenomenon in China ( Guo et al, 2014 ; An et al, 2019 ). Considerable attention has been paid to PM 2.5 particles because of their important roles in air quality and climate change ( Tao et al, 2012 ; Wang et al, 2018 ; Zheng et al, 2015 ; Rosenfeld et al, 2014 ).…”

Section: Introductionmentioning

confidence: 99%

Importance of meteorology in air pollution events during the city lockdown for COVID-19 in Hubei Province, Central China

Shen

Zhao

Wang

et al. 2021

Science of The Total Environment

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Compared with the 21-year climatological mean over the same period during 2000–2020, the aerosol optical depth (AOD) and Angstrom exponent (AE) during the COVID-19 lockdown (January 24–February 29, 2020) decreased and increased, respectively, in most regions of Central-Eastern China (CEC). The AOD (AE) values decreased (increased) by 39.2% (29.4%) and 31.0% (45.3%) in Hubei and Wuhan, respectively, because of the rigorous restrictions. These inverse changes reflected the reduction of total aerosols in the air and the contribution of the increase in fine-mode particles during the lockdown. The surface PM 2.5 had a distinct spatial distribution over CEC during the lockdown, with high concentrations in North China and East China. In particular, relatively high PM 2.5 concentrations were notable in the lower flatlands of Hubei Province in Central China, where six PM 2.5 pollution events were identified during the lockdown. Using the observation data and model simulations, we found that 50% of the pollution episodes were associated with the long-range transport of air pollutants from upstream CEC source regions, which then converged in the downstream Hubei receptor region. However, local pollution was dominant for the remaining episodes because of stagnant meteorological conditions. The long-range transport of air pollutants substantially contributed to PM 2.5 pollution in Hubei, reflecting the exceptional importance of meteorology in regional air quality in China.

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Source Contributions to PM2.5 under Unfavorable Weather Conditions in Guangzhou City, China

Cited by 20 publications

References 47 publications

Air Quality During COVID-19 Lockdown in the Yangtze River Delta and the Pearl River Delta: Two Different Responsive Mechanisms to Emission Reductions in China

Air Quality During COVID-19 Lockdown in the Yangtze River Delta and the Pearl River Delta: Two Different Responsive Mechanisms to Emission Reductions in China

PAN–Precursor Relationship and Process Analysis of PAN Variations in the Pearl River Delta Region

Importance of meteorology in air pollution events during the city lockdown for COVID-19 in Hubei Province, Central China

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