Modeling of aerosol property evolution during winter haze episodes over a megacity cluster in northern China: roles of regional transport and heterogeneous reactions of SO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;

Du, Huiyun; Li, Jie; Chen, Xueshun; Wang, Zifa; Sun, Yele; Fu, Pingqing; Li, Jianjun; Gao, Jian; Wei, Yang

doi:10.5194/acp-19-9351-2019

Cited by 36 publications

(17 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, aerosol characteristics in Beijing are influenced by regional transport from adjacent polluted regions. Polluted air masses from the southern regions contributed more secondary inorganic aerosols (SIAs) than primary aerosols in Beijing (Zhang et al, 2014;Du et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Rapid transition in winter aerosol composition in Beijing from 2014 to 2017: response to clean air actions

et al. 2019

View full text Add to dashboard Cite

Abstract. The clean air actions implemented by the Chinese government in 2013 have led to significantly improved air quality in Beijing. In this work, we combined the in situ measurements of the chemical components of submicron particles (PM1) in Beijing during the winters of 2014 and 2017 and a regional chemical transport model to investigate the impact of clean air actions on aerosol chemistry and quantify the relative contributions of anthropogenic emissions, meteorological conditions, and regional transport to the changes in aerosol chemical composition from 2014 to 2017. We found that the average PM1 concentration in winter in Beijing decreased by 49.5 % from 2014 to 2017 (from 66.2 to 33.4 µg m−3). Sulfate exhibited a much larger decline than nitrate and ammonium, which led to a rapid transition from sulfate-driven to nitrate-driven aerosol pollution during the wintertime. Organic aerosol (OA), especially coal combustion OA, and black carbon also showed large decreasing rates, indicating the effective emission control of coal combustion and biomass burning. The decreased sulfate contribution and increased nitrate fraction were highly consistent with the much faster emission reductions in sulfur dioxide (SO2) due to phasing out coal in Beijing compared to reduction in nitrogen oxides emissions estimated by bottom-up inventory. The chemical transport model simulations with these emission estimates reproduced the relative changes in aerosol composition and suggested that the reduced emissions in Beijing and its surrounding regions played a dominant role. The variations in meteorological conditions and regional transport contributed much less to the changes in aerosol concentration and its chemical composition during 2014–2017 compared to the decreasing emissions. Finally, we speculated that changes in precursor emissions possibly altered the aerosol formation mechanisms based on ambient observations. The observed explosive growth of sulfate at a relative humidity (RH) greater than 50 % in 2014 was delayed to a higher RH of 70 % in 2017, which was likely caused by the suppressed sulfate formation through heterogeneous reactions due to the decrease in SO2 emissions. Thermodynamic simulations showed that the decreased sulfate and nitrate concentrations have lowered the aerosol water content, particle acidity, and ammonium particle fraction. The results in this study demonstrate the response of aerosol chemistry to the stringent clean air actions and identify that the anthropogenic emission reductions are a major driver, which could help to further guide air pollution control strategies in China.

show abstract

Section: Introductionmentioning

confidence: 99%

Rapid transition in winter aerosol composition in Beijing from 2014 to 2017: response to clean air actions

et al. 2019

View full text Add to dashboard Cite

show abstract

“…6b). This result indicates that POA particles in the regional haze layer provided surfaces for the heterogeneous reactions of SO 2 and NO x , which promotes the formation of SIA on POA particles in the humid polluted air (Ebert et al, 2016;Zhang et al, 2017).…”

Section: Atmospheric Aging Of Poa Particlesmentioning

confidence: 86%

“…3a). These particles are stable under strong electron beams and appear as dark features in TEM images, reflecting their high thickness and refractory properties (Ebert et al, 2016;Liu et al, 2018). The SEM image acquired at a 75 • tilt angle shows that these particles did not deform upon impaction and retained high vertical dimensions ( Fig.…”

Section: Classification Of Individual Particle Typesmentioning

confidence: 97%

Persistent residential burning-related primary organic particles during wintertime hazes in North China: insights into their aging and optical changes

Liu

Zhang

et al. 2021

Atmos. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

Abstract. Primary organic aerosols (POAs) are a major component of PM2.5 in winter polluted air in the North China Plain (NCP), but our understanding of the atmospheric aging processes of POA particles and the resulting influences on their optical properties is limited. As part of the Atmospheric Pollution and Human Health in a Chinese Megacity (APHH-Beijing) program, we collected airborne particles at an urban site (Beijing) and an upwind rural site (Gucheng, Hebei province) in the NCP during 13–27 November 2016 for microscopic analyses. We confirmed that large numbers of light-absorbing spherical POA (i.e., tarball) and irregular POA particles with high viscosity were emitted from domestic coal and biomass burning at the rural site and were further transported to the urban site during regional wintertime hazes. During the heavily polluted period (PM2.5 > 200 µg m−3), more than 60 % of these burning-related POA particles were thickly coated with secondary inorganic aerosols (named as core–shell POA–SIA particles) through the aging process, suggesting that POA particles can provide surfaces for the heterogeneous reactions of SO2 and NOx. As a result, during the heavily polluted period, their average particle-to-core diameter ratios at the rural and urban sites increased to 1.60 and 1.67, respectively. Interestingly, we found that the aging process did not change the morphology and sizes of POA cores, indicating that the burning-related POA particles are quite inert in the atmosphere and can be transported over long distances. Using Mie theory we estimated that the absorption capacity of these POA particles was enhanced by ∼ 1.39 times in the heavily polluted period at the rural and urban sites due to the “lensing effect” of secondary inorganic coatings. We highlight that the lensing effect on burning-related POA particles should be considered in radiative forcing models and authorities should continue to promote clean energy in rural areas to effectively reduce primary emissions.

show abstract

“…Such regional pollution sources as BB and the coal and steel industries have a strong impact on the particulate chemical composition of the air in urban Beijing. Besides, according to model studies, air pollutants in such provinces as Hebei, Henan, and Shandong are transported to Beijing (Shi et al, 2019;Du et al, 2019). In these provinces, efforts have been made to abate emissions from the steel industry, power plants, and traffic.…”

Section: Discussionmentioning

confidence: 99%

Simultaneous Measurement of Urban and Rural Particles in Beijing, Part II: Case Studies of Haze Events and Regional Transport

Chen¹,

Shi²,

Cai³

et al. 2020

Preprint

View full text Add to dashboard Cite

Abstract. Two parallel field studies were conducted simultaneously at both urban and rural sites in Beijing from 11/01/2016 to 11/29/2016. Online single-particle chemical composition analysis was used as a tracer system to investigate the impact of heating activities and the formation of haze events. Central heating elevated EC-Nit, EC-Nit-Sul, and ECOC-Nit levels by 1.5&#8211;2.0 times due to the increased use of coal in the urban areas. However, in the rural areas, residential heating which mainly consumes low-quality coal and biomass burning elevated ECOC-Nit-Sul, Nak-Nit, and OC-Sul levels by 1.2&#8211;1.5 times. Four severe haze events (hourly PM2.5&#8201;>&#8201;200&#8201;&#181;g&#8201;m&#8722;3) occurred at both sites during the studies. In each event, a pattern of <q>transport and accumulation</q> was found. In the first stage, particles were regionally transported from the south or southwest and accumulated under air stagnations, creating the significant secondary formation. Consequently, the boosting of PM2.5 led to severe haze. At both sites, the severe haze occurred due to different patterns of local emission, transport, and secondary processes. At PG, the sulfate-rich residential coal burning particles were dominant. The regional transport between PG and PKU was simulated using the WRF-HYSPLIT model, confirming that the transport from PG to PKU was significant, but PKU to PG occurred occasionally. These cases can explain the serious air pollution in the urban areas of Beijing and the interaction between urban and rural areas. This study can provide references for enhancing our understanding of haze formation in Beijing.

show abstract

Modeling of aerosol property evolution during winter haze episodes over a megacity cluster in northern China: roles of regional transport and heterogeneous reactions of SO<sub>2</sub>

Cited by 36 publications

References 64 publications

Rapid transition in winter aerosol composition in Beijing from 2014 to 2017: response to clean air actions

Rapid transition in winter aerosol composition in Beijing from 2014 to 2017: response to clean air actions

Persistent residential burning-related primary organic particles during wintertime hazes in North China: insights into their aging and optical changes

Simultaneous Measurement of Urban and Rural Particles in Beijing, Part II: Case Studies of Haze Events and Regional Transport

Contact Info

Product

Resources

About