Investigating the impact of regional transport on PM2.5 formation using vertical observation during APEC 2014 Summit in Beijing - 王书肖教授课题组

During APEC (Asia-Pacific Economic Cooperation) Economic Leaders' 2014 Summit in Beijing, strict regional air emission control was implemented, providing a unique opportunity to investigate the transport and formation mechanism of fine particulate matter (PM2.5). This study explores the use of vertical observation methods to investigate the influence of regional transport on PM2.5 pollution in Beijing before and during the APEC Summit. Vertical profiles of extinction coefficient, wind, temperature and relative humidity were monitored. Three PM2.5 pollution episodes were analysed. In episode 1 (October 27th to November 1st), regional transport accompanied with the accumulation of pollutants under unfavourable meteorological conditions led to the pollution. In episode 2 (November 2nd to 5th), pollutants left from episode 1 were retained in the boundary layer for 2 days in the region and then settled down to the surface, leading to an explosive increase of PM2.5. The regional transport of aged aerosols played a crucial role in the heavy PM2.5 pollution. In episode 3 (November 6th to 11th), emission from large point sources had been controlled for several days while primary emissions from diesel vehicle might lead to the pollution. It is found that ground-level observation of meteorology condition and air quality could not fully explain the pollution process while vertical parameters (aerosol optical profile, wind profile, relatively humidity profile and temperature profile) improved the understanding of regional transport influence on heavy pollution process. Further vertical observations are needed to investigate the pollutants transport especially during the explosive increase pollution episode.

王书肖教授课题组

Investigating the impact of regional transport on PM<sub>2.5</sub> formation using vertical observation during APEC 2014 Summit in Beijing