广州地区SO42-、NO3-、NH4+与相关气体污染特征研究

本文获得了2009年12月1日至2011年12月31日广州二次无机离子(SO2-4、NO-3、NH+4)及相关反应性气体(NOx/SO2/HNO2/HNO3等)的小时浓度数据,并分析了其污染特征.研究结果表明:PM2.5的浓度季节变化特征为冬秋春夏,SO2-4的浓度季节变化特征为秋冬春夏,NH+4的为冬秋春夏,NO-3则为冬春秋夏,SO2-4、NO-3和NH+4之和占PM2.5的比重大小为秋夏春冬;硫氧化率(SOR)均大于0.1,秋冬季节的值高于春夏季节,与SO2-4的浓度变化趋势一致;氮氧化率(NOR)日变化呈单峰形式,最大值出现在06时,最小值出现在14时,春冬季节的值高于夏秋季节,与NO-3的浓度变化趋势一致;广州地区NH3/NH+4除10—12月外,其月均值均大于1;在典型过程中,SO2-4、NO-3、NH+4、SOR、NOR和NH3/NH+4与能见度的变化都存在较好的对应关系,说明广州地区低能见度与二次离子(SO2-4、NO-3、NH+4)的生成有关.

Characteristics of particulate SO42-, NO3-, NH4+ and related gaseous pollutants in Guangzhou

In this study, hourly water-soluble inorganic ions and related gaseous pollutants were continuously measured from December 2009 to December 2011 in Guangzhou, and their pollution characteristics were characterized. Results showed that the seasonal variation of the mass concentrations of PM_2.5, SO₄^2-, NH₄⁺ and NO₃^- was winter > autumn > spring > summer, autumn > winter > spring > summer, winter > autumn > spring > summer, and winter > spring > autumn > summer, respectively. The sum of SO₄^2-, NH₄⁺ and NO₃^- in PM_2.5 was in the order of winter > spring > autumn > summer. The diurnal variation of sulfate oxygenation efficiency (SOR) was greater than 0.1, and the values of SOR in autumn and winter were higher than those in spring and summer, in accord with the variations of SO₄^2- concentrations. Differently, the diurnal variation of nitrate oxygenation efficiency (NOR) showed a single peak at 6:00 LT and a trough at 14:00 LT. The values of NOR in spring and winter were higher than those in summer and autumn, similar to the trend of the seasonal variation of NO₃^- concentrations. The monthly means of NH₃/NH₄⁺ in Guangzhou were larger than 1 except from October to December. During haze days, SO₄^2-, NO₃^-, NH₄⁺, SOR, NOR and NH₃/NH₄⁺ were well correlated with visibility, implying the strong association between low visibility events in Guangzhou and formation of the secondary inorganic ions.