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| Study on the formation and the cause of the fog-haze transformation in the lover reaches of Huaihe River |
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Abstract Based on the soundings of temperature, surface meteorological parameters, air pollutants concentration, the multi-day widespread fog-haze processes and the transformation between fog and haze during June 2012 at the downstream of the Huai River were investigated. Surface layer breeze provided nice dynamic conditions for the longtime maintain fog-haze; the neutrosphere or the inversion layer near the surface supplied a thermodynamic conditions; the large-scale crop residue burning provided enough condensation nucleus. During the haze-fog process, the visibility reduced with the wind speed decrease, and lifted with the wind speed increase. The formation and development of moderate and severe haze were accompanied with increasing specific humidity, while the haze-fog conversion processes were accompanied with decreasing specific humidity. The higher the specific humidity, the longer the fog-haze duration. The higher the specific humidity before the fog, the lower the minimum visibility during the fog. Visibility was positively correlated with the concentration of SO2 (Pearson correlation coefficients is 0.42), but was inversely correlated with PM2.5 and PM10 concentrations (Pearson correlation coefficients are -0.49and -0.56, respectively). During the fog-haze processes, the upwind SO2, NO2 concentrations were higher than about 2times those of downwind. However, the downwind NO and PM10 concentrations were about 1.5 times higher than those of the upwind. Pollutants conversions occurred during the fog-haze processes.
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Received: 30 October 2013
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CHEN Huan-Yu, LIU Jing-Qing, WEI Zong-Yuan, ZHANG Hui-Hui, HE Xiao-Fang, ZHOU Xiao-Yan, QIU Shang-De, HU Bao-Lan, LOU Li-Ping. Radial differences in contaminant distribution in large-diameter pipe scales of main pipelines in drinking water distribution system[J]. CHINA ENVIRONMENTAL SCIENCECE, 2015, 35(9): 2706-2712. |
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