TY - JOUR
T1 - Persistent residential burning-related primary organic particles during wintertime hazes in North China
T2 - insights into their aging and optical changes
AU - Liu, Lei
AU - Zhang, Jian
AU - Zhang, Yinxiao
AU - Wang, Yuanyuan
AU - Xu, Liang
AU - Yuan, Qi
AU - Liu, Dantong
AU - Sun, Yele
AU - Fu, Pingqing
AU - Shi, Zongbo
AU - Li, Weijun
PY - 2021/2/16
Y1 - 2021/2/16
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=85100890185&partnerID=8YFLogxK
U2 - 10.5194/acp-21-2251-2021
DO - 10.5194/acp-21-2251-2021
M3 - Article
AN - SCOPUS:85100890185
SN - 1680-7316
VL - 21
SP - 2251
EP - 2265
JO - Atmospheric Chemistry and Physics
JF - Atmospheric Chemistry and Physics
IS - 3
ER -