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Meteorological factors and aerosol characteristics during two long-lasting fog/haze event in Xi¢an |
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Abstract Based on the meteorological and aerosol observed data, the change of wind, temperature ,humidity, aerosol mass concentration, particle size distribution and scatter coefficient had been analyzed in Xi`an on 17~25 December 2013 and 20~26 February 2014. These factors had an effect on the fog/Haze of formation, development and lasting. The results showed: By ASP observation, particle number concentration between 0.5μm and 0.835μm of aerodynamic diameter increased obviously during the formation and maintaining of fog/haze. After the process of fog/haze, the particle number concentration of aerodynamic diameter 3.5μm decreased significantly. By SMPS observation, particle number concentration was mainly concentrated in 30nm~300nm of aerodynamic diameter and had obvious diurnal variation during the formation and maintaining of fog/haze, the time of large particle number concentration appeared from 8a.m. to 2p.m and from 6p.m to 2a.m. The increase of pollutant concentration was mainly related to the increase of number concentration of aerodynamic diameter>140nm.The increase of scatter coefficient was related to the increase of number concentration of aerodynamic diameter<1.0μm. This was one of the important factors which caused the visibility deterioration.
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Received: 18 December 2014
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