China's emission control strategies have suppressed unfavorable influences of climate on wintertime PM 2.5 concentrations in Beijing since 2002

• Published in: Atmospheric Chemistry and Physics
• Main Authors: M. Gao, Z. Liu, B. Zheng, D. Ji, P. Sherman, S. Song, J. Xin, C. Liu, Y. Wang, Q. Zhang, J. Xing, J. Jiang, Z. Wang, G. R. Carmichael, M. B. McElroy
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2020
• Subjects: Physics; QC1-999; Chemistry; QD1-999; aleutian low
• Online Access: https://doi.org/10.5194/acp-20-1497-2020; https://doaj.org/article/62afec3a55694d01905dffe5f66fba83

Severe wintertime PM 2.5 pollution in Beijing has been receiving increasing worldwide attention, yet the decadal variations remain relatively unexplored. Combining field measurements and model simulations, we quantified the relative influences of anthropogenic emissions and meteorological conditions on PM 2.5 concentrations in Beijing over the winters of 2002–2016. Between the winters of 2011 and 2016, stringent emission control measures resulted in a 21 % decrease in mean mass concentrations of PM 2.5 in Beijing, with 7 fewer haze days per winter on average. Given the overestimation of PM 2.5 by the model, the effectiveness of stringent emission control measures might have been slightly overstated. With fixed emissions, meteorological conditions over the study period would have led to an increase in haze in Beijing, but the strict emission control measures have suppressed the unfavorable influences of the recent climate. The unfavorable meteorological conditions are attributed to the weakening of the East Asia winter monsoon associated particularly with an increase in pressure associated with the Aleutian Low.