PDF《黄石市大气 PM2 5 中水溶性离子浓度特征及来源分析》

5 samples were collected with a MiniVol portable air sampler from March

2012 to February

2013 in Huangshi City? Hubei Province. Nine water~soluble inorganic ions (NH4 + ? Ca2+ ? Mg2+ ? Na+ ? K+ ? Cl- ? NO3 - ? SO4 2- and F- ) were analyzed by ion chromatography (IC)? and the possible sources of these species were determined with the positive matrix factorization (PMF) method. The average mass concentrations of total water~soluble ions were (61? 5±26? 8)μgMm3 ? accounting for 63? 9% of the PM2?

5 mass. The concentrations of these species were in the order of ρ(SO4 2- ) >

ρ(NO3 - ) >

ρ(NH4 + ) >

ρ(Na+ ) >

ρ(Cl- ) >

ρ(Ca2+ ) >

ρ(K+ ) >

ρ(F- ) >

ρ(Mg2+ ). The water~soluble ions were mainly composed of secondary ions ( NH4 + ? NO3 - and SO4 2- )? accounting for 74? 4% of total water~soluble ions. The ratio of ρ( NO3 - ) to ρ(SO4 2- ) was in the range of 0? 12~1? 29? with a mean value of 0? 53±0? 30? indicating that anthropogenic stationary sources had more contributions to the atmospheric pollution in Huangshi City. The sulfur oxidation rate (SOR) and nitrogen oxidation rate (NOR) were greater than 0?

10 in the four seasons? suggesting that sulfate and nitrate in PM2?

5 were formed mainly through secondary transformation. The overall correlation between cations and anions in spring? summer? autumn and winter were strong (R2 = 0? 98)? and the annual PM2?

5 第7期郑敬茹等:黄石市大气 PM2?

5 中水溶性离子浓度特征及来源分析 components were partial acidic. PMF analysis indicated that the major sources of PM2?

5 were combustion? secondary transformation and soilMmineral dust. In conclusion? results showed that SNA were the main water~soluble ions in PM2?

5 in Huangshi City? and combustion? secondary transformation and soilMmineral dust were the main sources. Keywords: Huangshi City? PM2?

5 ? water~soluble ions? source? ion chromatography (IC) 大气颗粒物?特别是 PM2? 5(细颗粒物)对人体健 康[1~2] 、大气能见度[3~4] 和全球气候变化[5~6] 有重要影 响. PM2?

5 主要组分包括水溶性离子、碳组分、地壳元 素和各种微量元素等[7] . 水溶性离子作为颗粒物的 重要组分之一?对大气酸度、大气光学性质和能见度 等有显著影响[3?8~9] . 研究发现?水溶性离子是 PM2?

5 中的 重要组成部分? 可以占ρ(PM2?

5 ) 的40% 以上[10~11] ?灰霾期占比为50% ~ 60%[12] . SNA ( 为SO4 2- 、NO3 - 和NH4 + 的统称) 是大气二次气溶胶的重 要组成?主要来源于 SO2 的直接排放及 NOx 和NH3 的氧化作用?三者占比之和可在 80%以上[13] ?是造成 许多城市大气能见度降低的主要原因. Na+ 、K+ 、Ca2+ 和Mg2+ 则主要来源于自然源?如海盐、土壤和矿物扬 尘及森林大火[14] . 水溶性离子组成特征与颗粒物的 形成、增长和转化相关?因此要评价颗粒物的生态环 境影响与健康效应?就必须对颗粒物的水溶性离子组 成特征进行详细的调查研究. 近年来?国内外许多学者对 PM2?

5 中水溶性离子 的浓度水平、季节性变化、粒径分布、来源等进行了广 泛深 入地研究? 但大多集中在京津冀[15~17] 、 珠三角[18~19] 、长三角[20~23] 、成渝[24~25] 和关中盆地[26~29] 等地 区. 随着近几年我国雾霾污染影响范围的不断扩大? 如2013 年1月6―16 日我国中东部大范围、持续性 的雾霾?使得一些学者开始关注中部地区的大气环境 污染问题. 目前?对于我国华中地区大气颗粒物的研 究主要集中在武汉市等特大城市[30~33] ?而其他城市 大气 PM2?