The Relationship of PM Variation with Visibility and Mixing-Layer Height under Hazy/Foggy Conditions in the Multi-Cities of Northeast China.

Hujia Zhao,Huizheng Che,Hongbin Yang,Hong Wang,Yuche Liu,Xiaoye Zhang,Yaqiang Wang,Yanjun Ma,Yangfeng Wang

doi:10.3390/ijerph14050471

Abstract

The variations of visibility, PM-mass concentration and mixing-layer height (MLH) in four major urban/industry regions (Shenyang, Anshan, Benxi and Fushun) of central Liaoning in Northeast China are evaluated from 2009 to 2012 to characterize their dynamic effect on air pollution. The annual mean visibilities are about 13.7 ± 7.8, 13.5 ± 6.5, 12.8 ± 6.1 and 11.5 ± 6.8 km in Shenyang, Anshan, Benxi and Fushun, respectively. The pollution load (PM × MLH) shows a weaker vertical diffusion in Anshan, with a higher PM concentration near the surface. High concentrations of fine-mode particles may be partially attributed to the biomass-burning emissions from September in Liaoning Province and surrounding regions in Northeast China as well as the coal burning during the heating period with lower MLH in winter. The visibility on non-hazy fog days is about 2.5–3.0 times higher than that on hazy and foggy days. The fine-particle concentrations of PM2.5 and PM1.0 on hazy and foggy days are ~1.8–1.9 times and ~1.5 times higher than those on non-hazy foggy days. The MLH declined more severely during fog pollution than in haze pollution. The results of this study can provide useful information to better recognize the effects of vertical pollutant diffusion on air quality in the multi-cities of central Liaoning Province in Northeast China.

Highlights

The degradation of visibility has been widely studied as one of the key parameters indicative of air quality [1,2,3,4]
The high aerosol loading of anthropogenic origin sources in urban areas contributes to the worse visibility [15] and could influence local and regional air quality [16,17,18]
The atmospheric mixing layer height (MLH) is one of the important meteorological parameters that affect the vertical dispersion of air pollutants and has been studied worldwide [19,20,21,22,23,24]

Summary

Introduction

The degradation of visibility has been widely studied as one of the key parameters indicative of air quality [1,2,3,4]. Some studies have shown that visibility degradation has become more serious in urban areas than the rural regions because of the rapid urbanization with a corresponding increase in traffic and higher energy consumption [12,13,14]. The high aerosol loading of anthropogenic origin sources in urban areas contributes to the worse visibility [15] and could influence local and regional air quality [16,17,18]. The atmospheric mixing layer height (MLH) is one of the important meteorological parameters that affect the vertical dispersion of air pollutants and has been studied worldwide [19,20,21,22,23,24]

Objectives

Methods

Conclusion