A seriously sand storm mixed air-polluted area in the margin of Tarim Basin: Temporal-spatial distribution and potential sources

Abstract

In order to analyze the temporal-spatial distribution characteristics of PM2.5, PM10, SO2, NO2, CO and O3 in five cities and the potential sources of PM10 in southern Xinjiang during 2016, we collected one year officially released data for analysis. The average PM10, PM2.5, SO2, NO2, O3 and CO concentrations were 289 ± 363, 99 ± 106, 17 ± 9, 29 ± 11, 65 ± 25 μg m−3 and 1.3 ± 0.6 mg m−3 in southern Xinjiang in 2016, respectively. The air pollutants presented distinct seasonal and spatial distribution characteristics. During sandstorm process, the particulate matters (PM) concentrations increased abruptly, with the PM10 and PM2.5 maximum concentrations exceeding 1000 and 500 μg m−3 in each city. The backward trajectory results showed that the air masses in Akesu, Kurla, Hotan, Kashi and Atushi were mainly from the Bayingol Mongolian Autonomous Prefecture, Kyrgyzstan, Kizilesu Kirgiz Autonomous Prefecture and Taklimakan Desert (TD). In addition, TD was the main potential contributor to ambient PM10 in five cities during the dust season (DS), with a weighted potential source contribution function (WPSCF) > 0.9. While the trajectories of air masses from TD, Bayingol Mongolian Autonomous Prefecture, Urumqi-Changji Area and local emission were potential sources contributing to PM2.5 in these five cities during DS, with a WPSCF > 0.7. Moreover, the high weighted concentration weighted trajectory (WCWT) values were distributed in the Tarim basin, with PM10 > 700 μg m−3, however, the local emission and long distance transport contributed to the PM2.5 > 160 μg m−3 for five cities. This study comprehensively analyzes the pollution characteristics of air pollutants in five important cities in the southern margin of the Tarim Basin for the first time, and will provide an important reference basis for the prevention and control of air pollution in southern Xinjiang.