TY - JOUR

T1 - Effectiveness of short-term air quality emission controls

T2 - a high-resolution model study of Beijing during the Asia-Pacific Economic Cooperation (APEC) summit period

AU - Ansari, Tabish

AU - Wild, Oliver

AU - Li, J.

AU - Yang, T.

AU - Xu, W.

AU - Sun, Y.

AU - Wang, Z.

PY - 2019/7/9

Y1 - 2019/7/9

N2 - We explore the impacts of short-term emission controls on haze events in Beijing in October-November 2014 using high-resolution Weather Research and Forecasting model with Chemistry (WRF-Chem) simulations. The model reproduces surface temperature and relative humidity profiles over the period well and captures the observed variations in key atmospheric pollutants. We highlight the sensitivity of simulated pollutant levels to meteorological variables and model resolution and in particular to treatment of turbulent mixing in the planetary boundary layer. We note that simulating particle composition in the region remains a challenge, and we overpredict span classCombining double low line"inline-formula"NH4/span and span classCombining double low line"inline-formula"NO3/span at the expense of span classCombining double low line"inline-formula"SO4/span. We find that the emission controls implemented for the Asia-Pacific Economic Cooperation (APEC) summit period made a relatively small contribution to improved air quality (20 %-26 %), highlighting the important role played by favourable meteorological conditions over this period. We demonstrate that the same controls applied under less favourable meteorological conditions would have been insufficient in reducing pollutant levels to meet the required standards. Continued application of these controls over the 6-week period considered would only have reduced the number of haze days when daily mean fine particulate matter exceeds 75 span classCombining double low line"inline-formula"μg m-3/span from 15 to 13 d (days). Our study highlights the limitations of current emission controls and the need for more stringent measures over a wider region during meteorologically stagnant weather.

AB - We explore the impacts of short-term emission controls on haze events in Beijing in October-November 2014 using high-resolution Weather Research and Forecasting model with Chemistry (WRF-Chem) simulations. The model reproduces surface temperature and relative humidity profiles over the period well and captures the observed variations in key atmospheric pollutants. We highlight the sensitivity of simulated pollutant levels to meteorological variables and model resolution and in particular to treatment of turbulent mixing in the planetary boundary layer. We note that simulating particle composition in the region remains a challenge, and we overpredict span classCombining double low line"inline-formula"NH4/span and span classCombining double low line"inline-formula"NO3/span at the expense of span classCombining double low line"inline-formula"SO4/span. We find that the emission controls implemented for the Asia-Pacific Economic Cooperation (APEC) summit period made a relatively small contribution to improved air quality (20 %-26 %), highlighting the important role played by favourable meteorological conditions over this period. We demonstrate that the same controls applied under less favourable meteorological conditions would have been insufficient in reducing pollutant levels to meet the required standards. Continued application of these controls over the 6-week period considered would only have reduced the number of haze days when daily mean fine particulate matter exceeds 75 span classCombining double low line"inline-formula"μg m-3/span from 15 to 13 d (days). Our study highlights the limitations of current emission controls and the need for more stringent measures over a wider region during meteorologically stagnant weather.

U2 - 10.5194/acp-19-8651-2019

DO - 10.5194/acp-19-8651-2019

M3 - Journal article

VL - 19

SP - 8651

EP - 8668

JO - Atmospheric Chemistry and Physics

JF - Atmospheric Chemistry and Physics

SN - 1680-7316

IS - 13

ER -