摘要
2012年11~12月在青岛采集58套denuder和PM2.5样品,分析了其中酸碱气体及相应的颗粒态组分浓度,探讨了它们的浓度特征和气粒平衡关系.青岛大气中HNO3、HNO2、HCl、SO2和NH3平均浓度分别为1.36、1.64、1.46、27.58和2.95μg·m-3.PM2.5中NO-3、NO-2、Cl-、SO2-4和NH+4浓度分别为6.49、0.12、1.95、9.36和6.04μg·m-3.霾天大气中酸碱气体浓度较之晴天时的增幅明显低于PM2.5中相应离子浓度的增幅;雾天时,除HNO2外其他气体浓度均低于晴天,但PM2.5中相应离子浓度较之晴天时均有明显增加.采样期间青岛大气为富氨环境,PM2.5中NH+4主要以(NH4)2SO4的形式存在,NO-3生成主要受HNO3的限制.利用ISORROPIAⅡ模型探讨了青岛PM2.5中二次离子的控制因子,通过敏感性实验发现NH+4对总NH3(TNH3)变化响应不敏感,但对总H2SO4(TSO4)和总HNO3(TNO3)变化响应敏感;NO-3和SO2-4则分别仅对TNO3和TSO4变化响应敏感,这暗示了减少TNO3和TSO4而不是TNH3的排放对降低青岛大气中PM2.5浓度更有效.
Fifty-eight samples were collected in Qingdao from November to December 2012 using a PM2. 5sampler. Concentrations of acidic gases,ammonia and their partner ions in PM2. 5were determined,and the correlation between concentrations and the gas-particle partitioning were analyzed. The averaged concentrations of HNO3,HNO2,HCl,SO2 and NH3in atmosphere samples of Qingdao were1. 36,1. 64,1. 46,27. 58 and 2. 95 μg·m- 3,respectively,for the concentrations of NO-3,NO-2,Cl-,SO2-4and NH+4in PM2. 5were6. 49,0. 12,1. 95,9. 36 and 6. 04 μg·m- 3,respectively. When the measurements made in haze days,compared to those made in clear days,the concentration of these ions in PM2. 5increased more than those of acidic gases and ammonia; In foggy days,the concentrations of gases were lower than those in clear days except HNO2,while the reverse was true for the concentrations of all particulate species in PM2. 5. During whole study period,the NH3 level was high and the NH+4in PM2. 5in Qingdao was mainly present as( NH4)2SO4. The analysis results suggested that formation of NO-3were mainly determined by HNO3. To further explore the control factors of these species in PM2. 5,the thermodynamic equilibrium model of ISORROPIA Ⅱ was employed. Our sensitivity tests showed that the formation of NH+4was less sensitive to the change of total NH3( TNH3),but sensitive to the changes of total H2SO4( TSO4)and total HNO3( TNO3). The formation of NO-3and SO2-4was sensitive to the changes of TNO3 and TSO4,respectively. Taken together,our findings implied that the reduction of TNO3 and TSO4rather than TNH3 appears to be more effective in lowering mass concentrations of PM2. 5in Qingdao.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2015年第9期3135-3143,共9页
Environmental Science
基金
国家重大科学研究计划项目(2014CB953701)
国家自然科学基金项目(41176097
41210008)
