Characteristics of Aerosol Liquid Water Content in Xiamen and Its Effect on Nitrate Production
Ambient aerosols contain a large number of hygroscopic components,which can absorb liquid water,and then change the size of aerosols and their environmental and climate effects.Therefore,it is necessary to study the aerosol liquid water(ALW)content(ALWC).The ambient air in Xiamen is rich in water vapor,and ALWC accounts for a large proportion in aerosols,and its characteristics and driving factors are lack of relevant reports.In this paper,the content and characteristics of main hygroscopic substances in PM2.5,as well as the seasonal and diurnal variations of ALWC in Xiamen were analyzed by using the ISORROPIAⅡ thermodynamic equilibrium model.The main factors affecting ALWC and degree of influence were also studied.The contribution of secondary ions to aerosol hygroscopicity was the largest in Xiamen,and its concentration was the highest in winter.The average level of ALWC in Xiamen was the highest in rainy season,reaching 113.5 μg/m3.The average proportion of ALWC in the total mass concentration of PM2.5 was 37.1%-86.6%.There was a negative correlation between visibility and ALWC in Xiamen.The concentration level of ALWC determined the overall situation of atmospheric visibility.Using sensitivity analysis method,it was found that sulfate had a significant effect on ALWC,and their concentration was linear.When nitrate concentration was low,it also had a linear correlation with ALWC,but when its concentration reached a certain level,it had no obvious effect on ALWC.In Xiamen,temperature change had little effect on ALWC,while RH had an exponential effect on ALWC.ALW had a significant promotion effect on the formation of nitrate.The analysis of the ratio of nitrate formation rate and ALWC revealed that the promotion ability of ALW on the formation of nitrate was stronger during the daytime.In addition,the strongest promotion ability of unit concentration of ALW for the formation of nitrate was observed in autumn.
NETL
NSTL
万方数据
维普
