上海大气颗粒物中溴、碘浓度水平的影响因素

统计分析了2008年采样期间大气颗粒物TSP和PM10中溴、碘浓度水平与气象条件和气态污染物SO2、NO2的关系。结果表明,风向为向岸流时,大气中TSP、PM10浓度以及颗粒物中溴、碘的浓度均低于离岸流时的数值;在各气象因素中,影响颗粒物中溴、碘浓度的主要气象因素为风向、气压和气温,风速和相对湿度的影响较小;颗粒物中溴、碘的浓度水平随大气中SO2、NO2浓度的上升而上升,颗粒物中碘与SO2、NO2呈显著正相关,而颗粒物中溴呈较弱的正相关性;当空气质量恶化时,PM10中Br、I浓度增大,而Br/I比值降低,城市大气中污染物质之间的化学反应对颗粒物中Br/I的比值有一定影响。

Influencing Factors of Bromine and Iodine Concentration Levels in Atmospheric Particulates in Shanghai

Aerosol samples including TSP and PM10 particulate were collected in 2008 to analyze the concentration levels of trace elements Br and I. Statistical analysis was done to investigate the relationship between bromine and iodine concentration levels with gaseous pollutants such as SO2 and NO2 as well as meteorological conditions. Results showed that when wind flowed to the shore,the concentrations of TSP and PM10,particulate bromine and particulate iodine were lower than values in the offshore flow. The wind direction,air pressure and air temperature were major factors in influencing the concentration of Br and I in aerosols,while wind speed and relative humidity were minor factors. Concentrations of Br,I in aerosols increased with the concentration of SO2 and NO2 increasing. Iodine in aerosols showed a highly positive correlation with SO2 and NO2,whereas for Br,it only weakly correlated with the pollutants. When air quality deteriorated,the concentrations of Br,I in PM10 increased and Br/I ratio decreased,which indicated that chemical reaction among urban air pollutants would affect Br/I ratio in aerosols.