Characteristics and source apportionment of fine haze aerosol in Beijing during the winter of 2013

Xiaona Shang, Kai Zhang, Fan Meng, Shihao Wang, Meehye Lee, Inseon Suh, Daigon Kim, Kwonho Jeon, Hyunju Park, Xuezhong Wang, Yuxi Zhao
2018 Atmospheric Chemistry and Physics  
<p><strong>Abstract.</strong> For PM<sub>2.5</sub> filter samples collected daily at the Chinese Research Academy of Environmental Sciences (Beijing, China) from December of 2013 to February of 2014 (the winter period), chemical characteristics and sources were investigated with an emphasis on haze events in different alert levels. During the 3 months, the average PM<sub>2.5</sub> concentration was 89<span class="thinspace"></span>µg<span class="thinspace"></span>m<sup>−3</sup>, exceeding the
more » ... p>, exceeding the Chinese national standard of 75<span class="thinspace"></span>µg<span class="thinspace"></span>m<sup>−3</sup> in 24<span class="thinspace"></span><span class="thinspace"></span>h. The maximum PM<sub>2.5</sub> concentration was 307<span class="thinspace"></span>µg<span class="thinspace"></span>m<sup>−3</sup>, which characterizes developed-type pollution (PM<sub>2.5</sub><span class="thinspace"></span>/<span class="thinspace"></span>PM<sub>10</sub><i>&amp;gt;</i>0.5) in the World Health Organization criteria. PM<sub>2.5</sub> was dominated by SO<sub>4</sub><sup>2−</sup>, NO<sub>3</sub><sup>−</sup>, and pseudo-carbonaceous compounds with obvious differences in concentrations and proportions between non-haze and haze episodes. The non-negative matrix factorization (NMF) analysis provided reasonable PM<sub>2.5</sub> source profiles, by which five sources were identified: soil dust, traffic emission, biomass combustion, industrial emission, and coal combustion accounting for 13, 22, 12, 28, and 25<span class="thinspace"></span><span class="thinspace"></span>% of the total, respectively. The dust impact increased with northwesterlies during non-haze periods and decreased under stagnant conditions during haze periods. A blue alert of heavy air pollution was characterized by the greatest contribution from industrial emissions (61<span class="thinspace"></span><span class="thinspace"></span>%). During the Chinese Lantern Festival, an orange alert was issued and biomass combustion was found to be the major source owing to firework explosions. Red-alert haze was almost equally contributed by local traffic and transported coal combustion emissions from the vicinity of Beijing (approximately 40<span class="thinspace"></span><span class="thinspace"></span>% each) that was distinguished by the highest levels of NO<sub>3</sub><sup>−</sup> and SO<sub>4</sub><sup>2−</sup>, respectively. This study also reveals that the severity and source of haze are largely dependent on meteorological conditions.</p>
doi:10.5194/acp-18-2573-2018 fatcat:wira7d7vwnd3bkvqx3xkoifix4