Chemical characteristics and sources of PM1 during the 2016 summer in Hangzhou

Li, Kangwei; White, Stephen; Zheng, Xianjue; Lv, Biao; Lin, Changpo; Bao, Zhier; Wu, Xuecheng; Gao, Xiang; Fang, Ying; Shen, Jiandong; Azzi, Merched; Cen, Kefa

doi:10.1016/j.envpol.2017.09.016

Cited by 35 publications

(5 citation statements)

References 52 publications

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“…We found that the BC concentration in Hangzhou (1.29 μg/m 3 ) during COVID‐1ock was much lower than that (3.2 μg/m 3 ) in Beijing during the 2008 Olympics (Okuda et al, 2011) and the concentration (2.5 μg/m 3 ) during the 2014 APEC (Zhang, Li, et al, 2018) but was close to that (1.20 μg/m 3 ) during the 2015 China Victory Day parade (Zhao et al, 2017). The 44% BC reduction from the COVID‐19 lockdown to the pre‐COVID period is twice as much as the control periods during the 2016 G20 summit in Hangzhou (Li et al, 2018). These comparisons show that the BC during the COVID‐19 lockdown maintained the lowest concentration in the megacity.…”

Section: Resultsmentioning

confidence: 99%

“…Controlling anthropogenic emissions is an effective way to mitigate the air pollution level. Various emission reduction campaigns have been employed to improve the local air quality during several major events, including the 2008 Beijing Olympic (Okuda et al, 2011), the 2014 Asia-Pacific Economic Cooperation (APEC) meeting (Zhang, Li, et al, 2018), the 2015 China Victory Day Parade (Zhao et al, 2017), and the 2016 G20 summit (Li et al, 2018). During these special events, some factories with high emissions were temporarily closed, construction activities were stopped, and the number of vehicles was restricted (Sun et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

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Variation in Concentration and Sources of Black Carbon in a Megacity of China During the COVID‐19 Pandemic

Zhang

Sun

et al. 2020

Geophysical Research Letters

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Black carbon (BC) not only warms the atmosphere but also affects human health. The nationwide lockdown due to the Coronavirus Disease 2019 (COVID-19) pandemic led to a major reduction in human activity during the past 30 years. Here, the concentration of BC in the urban, urban-industry, suburb, and rural areas of a megacity Hangzhou were monitored using a multiwavelength Aethalometer to estimate the impact of the COVID-19 lockdown on BC emissions. The citywide BC decreased by 44% from 2.30 to 1.29 μg/m 3 following the COVID-19 lockdown period. The source apportionment based on the Aethalometer model shows that vehicle emission reduction responded to BC decline in the urban area and biomass burning in rural areas around the megacity had a regional contribution of BC. We highlight that the emission controls of vehicles in urban areas and biomass burning in rural areas should be more efficient in reducing BC in the megacity Hangzhou. As the first country reporting and fighting Coronavirus Disease 2019 (COVID-19), China has implemented a series of effective measures to prevent the spread of COVID-19, including stay-at-home orders, travel bans, shutting down nonessential commercial activities, and a national lockdown (Tian et al., 2020). These nationwide restrictions have led to the lowest human activity in modern China in the past 30 years, resulting in the

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Variation in Concentration and Sources of Black Carbon in a Megacity of China During the COVID‐19 Pandemic

Zhang

Sun

et al. 2020

Geophysical Research Letters

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“…The composition of SOA was determined by a high-resolution time of flight aerosol mass spectrometry (HR-ToF-AMS, hereafter AMS; Aerodyne Research Inc., USA), with method described in detail in our previous studies 57,58 . In brief, the AMS was operated in the high sensitivity V-mode and the high resolution W-mode every 2 min, alternately.…”

Section: Instrumentation and Analysismentioning

confidence: 99%

Suppression of anthropogenic secondary organic aerosol formation by isoprene

Zhang

Zhao

et al. 2022

npj Clim Atmos Sci

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Secondary organic aerosol (SOA) represents a major fraction of atmospheric fine particles. Both biogenic and anthropogenic volatile organic compounds (VOCs) can contribute to SOA through (photo-) oxidation. However, the current understanding of their combined, interactive effect on SOA formation and composition is still limited, challenging the accuracy in assessing global SOA budget, sources, and climate effect. Here we combine laboratory experiments and modelling to show that isoprene can suppress SOA formation from photo-oxidation of anthropogenic aromatics (toluene and p-xylene) with the presence of NOx, and similar SOA suppression phenomena are observed when replacing isoprene with propene. We find that the decreased SOA in such mixed-VOC conditions can be largely attributed to OH scavenging effect, resulting in reduced consumption of parent aromatics. However, various changes in SOA oxidation state (i.e., O/C) and oxidation pathways (i.e., more carbonyls formation) are observed following addition of isoprene, and the SOA chemical composition may not be similar to any single parent hydrocarbon, which implies the existence of complex interactions between the degradation chemistry for alkenes and aromatics. Under the conditions of this work, the OH scavenging effect is largely determined by gas-phase chemistry, which is expected to be widespread in binary or more complex systems in ambient air. More broadly, we infer that the global budget of anthropogenic SOA and its corresponding radiative forcing could be affected by biogenic emission of isoprene, particularly in urban environments with appreciable vegetation coverage.

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“…It is representative and instructive for similar cities to conduct research on the sources and characteristics of aerosol particles (i.e., PM 10 and PM 2.5 ) and gaseous pollutants (i.e., NO x , SO 2 , O 3 , and CO) in Hangzhou ( Liu et al, 2015 ; Wu et al, 2016 ; Zhang et al, 2018 ). Several studies focused on the assessment of control strategies for air pollution reduction during some mega-events, such as the World Internet Conference in 2015 and the G20 summit in 2016, which were held in Hangzhou ( Feng et al, 2018 ; Ji et al, 2018 ; Li et al, 2018 ; Ni et al, 2018 ). A study from the WRF-Chem model showed that long-range transport contributed 30%–85% of PM 2.5 in Hangzhou ( Ni et al, 2018 ).…”

Section: Introductionmentioning

confidence: 99%

Spatiotemporal variations and reduction of air pollutants during the COVID-19 pandemic in a megacity of Yangtze River Delta in China

Yuan

et al. 2021

Science of The Total Environment

101

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In recent decades, air pollution has become an important environmental problem in the megacities of eastern China. How to control air pollution in megacities is still a challenging issue because of the complex pollutant sources, atmospheric chemistry, and meteorology. There is substantial uncertainty in accurately identifying the contributions of transport and local emissions to the air quality in megacities. The COVID-19 outbreak has prompted a nationwide public lockdown period and provides a valuable opportunity for understanding the sources and factors of air pollutants. The three-month period of continuous field observations for aerosol particles and gaseous pollutants, which extended from January 2020 to March 2020, covered urban, urban-industry, and suburban areas in the typical megacity of Hangzhou in the Yangtze River Delta in eastern China. In general, the concentrations of PM 2.5 – 10 , PM 2.5 , NO x , SO 2 , and CO reduced 58%, 47%, 83%, 11% and 30%, respectively, in the megacity during the COVID-Lock period. The reduction proportions of PM 2.5 and CO were generally higher in urban and urban-industry areas than those in suburban areas. NO x exhibited the greatest reduction (>80%) among all the air pollutants, and the reduction was similar in the urban, urban-industry, and suburban areas. O 3 increased 102%–125% during the COVID-Lock period. The daytime elevation of the planetary boundary layer height can reduce 30% of the PM 10 , PM 2.5 , NO x and CO concentrations on the ground in Hangzhou. During the long-range transport events, air pollutants on the regional scale likely contribute 40%–90% of the fine particles in the Hangzhou urban area. The findings highlight the future control and model forecasting of air pollutants in Hangzhou and similar megacities in eastern China.

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Chemical characteristics and sources of PM1 during the 2016 summer in Hangzhou

Cited by 35 publications

References 52 publications

Variation in Concentration and Sources of Black Carbon in a Megacity of China During the COVID‐19 Pandemic

Variation in Concentration and Sources of Black Carbon in a Megacity of China During the COVID‐19 Pandemic

Suppression of anthropogenic secondary organic aerosol formation by isoprene

Spatiotemporal variations and reduction of air pollutants during the COVID-19 pandemic in a megacity of Yangtze River Delta in China

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