AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Insights into a Haze Episode over a Coastal City Based on Multiple Measurements and Modeling Study
XIN WU, Junjun Deng, Youwei Hong, Lingling Xu, Lisi Zhao, Jinsheng Chen, Institute of Urban Environment, Chinese Academy of Sciences
Abstract Number: 262 Working Group: Regional and Global Air Quality and Climate Modeling
Abstract To further investigate the aerosol characteristics and probable causes of atmospheric pollution, a severe accumulated regional haze episode over a coastal city Xiamen, China, was diagnosed. Daily samples were collected to analyze the chemical components of fine particulate matters (PM2.5). Aerosol optical properties were acquired through a sun-photometer. The results show that stagnant meteorological conditions played a key role in the accumulation of aerosol particles during this episode. The height of the planetary boundary layer (PBL) was considered as one of the key factors together with other factors in the haze formation. Aerosol optical depth (AOD), light extinction coefficient and depolarization ratio in surface layer indicate that PM2.5 dominated this haze event. A negative correlation was found between the concentrations of PM2.5 and visibility. The distributions of gas pollutants (SO2, NOx and CO) were similar to that of fine particulate matters. Rising temperature, high relative humidity and low wind speed were the inducements of this episode. Water-soluble inorganic ions (WSIIs), organic carbon (OC) and elemental carbon (EC) were detected to elaborate the probable sources. Secondary inorganic ions and secondary organic carbon significantly influenced this haze episode. Backward trajectories results indicate that local circulation and slow air-mass prevented the diffusion of atmospheric pollutants. Simulated results of concentration of PM2.5 and surface wind field by WRF-CMAQ demonstrate the evolution of this haze episode, indicating that this episode was mainly caused by local emission, barely by long-ranged transportation from north. Pollution accumulated by local emission, secondary aerosol formation and the stagnant meteorological conditions dominated the formation of this haze episode.