摘要
依托河北省灰霾污染防治重点实验室,对2018年10月31日至12月3日期间石家庄市大气PM2.5的质量浓度和化学组分进行连续在线观测,解析石家庄市秋末冬初典型灰霾过程的特征.观测期间,石家庄市共发生4次霾污染过程,PM2.5均为首要污染物,日均浓度最大值分别为154、228、379和223μg·m^-3,达到重度污染甚至严重污染.PM2.5主要组分为无机水溶性离子(WSII)和含碳气溶胶,两者质量浓度的平均占比分别为(60.7±15.6)%和(21.6±9.7)%.相比优良天,两者浓度分别上升了4.4倍和3.1倍,是霾污染形成的主要原因.WSII中NO3^-为首要成分,SO4^2-和NH4^+次之,三者(SNA)质量浓度之和占WSII质量浓度的(91.5±17.3)%,污染期间SNA的暴发式增长是推高PM2.5浓度的主要原因.非高湿条件下,单位质量NO3^-和SO4^-的变化速率差异不明显,高湿条件触发SO2的液相氧化过程后,SO4^2-二次转化被显著促进.大气处于富NH3状态,PM2.5中n(NH4^+)与n(NO3^-+2×SO4^2-)的比值>1,过量NH3加剧NO3^-和SO4^2-的转化.霾污染时段,燃煤和机动车排放的一次污染物的积累为含碳气溶胶浓度上升的主要原因,相比优良天,二次有机碳的生成受到抑制.在采暖季开始之前的两次霾污染过程,移动源为PM2.5首要污染源,平均占比30.8%和39.8%.随着燃煤采暖污染排放的增加,燃煤源贡献逐步增高至25.2%,攀升为首要污染源.
The mass concentration and chemical composition of fine particles were continuously observed on-line from October 31 to December 3,2018 at Hebei Key Laboratory of Haze Pollution Prevention and Control in Shijiazhuang.The characteristics of haze pollution in autumn and winter in Shijiazhuang were analyzed.The results showed that during the observation period,four haze pollution episodes occurred with PM2.5 as the primary pollutant,and the maximum daily concentration was 154,228,379,and 223μg·m-3,respectively,reaching a heavy pollution level or above.The main components of PM2.5 were water-soluble inorganic ions(WSII)and carbon-containing aerosols,accounting for(60.7±15.6)%and(21.6±9.7)%of PM 2.5 mass concentration,respectively.Compared with clean days,the mass concentration of WSII and carbon aerosol during haze pollution increased by 4.4 times and 3.1 times,respectively,which was the main cause of haze pollution.NO3^-,SO4^2-,and NH+4(SNA)were the main components of WSII,accounting for(91.5±17.3)%of the total WSII concentration,of which NO3^- took up the highest proportion.The explosive growth of SNA during haze pollution was the main reason for the extremely high PM2.5 concentration.Under non-high humidity conditions,the formation rates of unit mass substrates(NO-3,SO4^2-)were not significantly different,but the transformation of SO4^2- was significantly promoted after the liquid phase oxidation of SO2 was triggered under high humidity conditions.The atmosphere in Shijiazhuang is rich in NH 3,and the molar ratio of n(NH4^+)to n(NO3^-+2×SO4^2-)in PM2.5 was greater than 1.The presence of a large amount of NH3 could promote the transformation of NO3^- and SO4^2- and aggravate pollution.During the haze pollution period,the accumulation of primary pollutants from coal and motor vehicles was the main reason for the increase in carbon-containing aerosol.Compared with clean days,the formation of SOC was inhibited.Before the beginning of the warm season,the mobile form was the main pollution source of PM2.5,contributing 30.8%and 39.8%of PM2.5 mass concentration.With the increase of coal combustion emissions,the contribution of coal-fired sources gradually increased to 25.5%,becoming the primary pollution source.
作者
宿文康
鲍晓磊
倪爽英
赵卫凤
SU Wen-kang;BAO Xiao-lei;NI Shuang-ying;ZHAO Wei-feng(Hebei Provincial Academy of Environmental Sciences,Shijiazhuang 050037,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2019年第11期4755-4763,共9页
Environmental Science
基金
国家重点研发计划项目(2017YFC0213006,2017YFC0213002)
关键词
霾污染
PM2.5成分分析
无机水溶性离子
含碳气溶胶
来源解析
石家庄市
haze pollution
PM2.5 component analysis
water-soluble inorganic ions
carbon-containing aerosols
source apportionment
Shijiazhuang
