Index Geophysics

Day-Night Differences, Seasonal Variations and Source Apportionment of PM10-Bound PAHs over Xi’an, Northwest China

Day-night PM10-bound PAHs were studied at an urban site of Xi’an from 20 December 2006 to 28 October 2007. The annual mean concentration of nighttime PAHs (285.0 ng m−3) was higher than that in daytime (239.4 ng m−3). A significant difference of PAH concentrations between daytime and nighttime was found in autumn with a coefficient of divergence (CD) of 0.23 (significant level 0.2). However, no distinct difference was observed in other seasons (with CD values < 0.2), although the difference of PAHs partition capacity in PM10 between daytime and nighttime was significant in the four seasons. Remarkable seasonal variations were observed in the total PAH levels, with a highest mean concentration of 344.6 ng m−3 in winter and a lowest mean concentration of 177 ng m−3 in summer. Positive matrix factorization results revealed that residential emission for heating is the major contributor of the elevated PAH levels in winter, accounting for 49% of the total PAH levels. The coal combustion including industrial and residential usage, contributed over 40% of the PAH emissions in PM10 of Xi’an during the one-year sampling period. These results can provide guidance for taking measures in reducing PAHs levels in the air.

Xin Wang

Zhenxing Shen

Yaling Zeng

Fobang Liu

Qian Zhang

Yali Lei

Hongmei Xu

Junji Cao

Liu Yang

PM10

PAHs

day-night difference

seasonal variation

positive matrix factorization

northwest China

Meteorology. Climatology

QC851-999

MDPI AG

2018-02-01T00:00:00Z

article

2073-4433

10.3390/atmos9020062

https://doaj.org/article/c3c0ae51bf70493ba6b98c538855e6ba

Atmosphere, Vol 9, Iss 2, p 62 (2018)

EN

http://www.mdpi.com/2073-4433/9/2/62

https://doaj.org/toc/2073-4433

Journal Licence: CC BY