• 关键词：麦秸焚烧  因子分析  细粒子  污染特征

• 基金项目：北京市科委“北京市空气质量达标战略研究”项目(No.H030630540320)

• 李金香
• 北京市环境保护监测中心, 北京 100044

• 赵越
• 北京市环境保护监测中心, 北京 100044

• 李令军
• 北京市环境保护监测中心, 北京 100044

• 杨晓光
• 北京市环境保护监测中心, 北京 100044

• 李海军
• 北京市环境保护监测中心, 北京 100044

• 董欣
• 北京市环境保护监测中心, 北京 100044

• 李云婷
• 北京市环境保护监测中心, 北京 100044

• 摘要：为了全面评价农田秸秆焚烧产生的污染事件,并为制定有效的管理措施提供依据,于2006年6月20日监测了西南风下北京南部农田麦秸焚烧产生的污染物向北京传输的过程,获得了SO₂、CO、NO_x以及可吸入颗粒物(PM₁₀)质量浓度的数据、颗粒物的化学组分数据.数据分析结果表明,污染输送对北京市西南部地区空气质量影响最大(PM₁₀小时浓度超过600μg·m^-3),对北部山区影响较小(PM₁₀浓度峰值在110μg·m^-3),高浓度污染在市区持续时间最长.麦秸焚烧通过输送增加了PM₁₀(尤其是PM₁)、CO、NO₂以及NMHC等污染物质,这使得与前一日相比污染物之间的相关关系发生了变化:SO₂与其它污染物的相关性不显著,而CO与NO₂、CH₄与NO显著相关.因子分析进一步揭示,气象条件对污染物浓度变化具有主导作用,而由麦秸焚烧所产生的外来污染源属于次要地位.污染输送过程中,PM_2.5中的硝酸盐类和有机碳、碳黑质量浓度增大.麦秸焚烧所输送的气态污染物和细小颗粒物对人体健康存在威胁,在不利扩散的气象条件下在大气中存留时间加长.研究结果表明,气象条件不利于污染扩散时必须禁止农田秸秆焚烧.

• Abstract：A wide range of open burning of wheat stubble occurred south of Beijing on June 20,2006,and consequently polluted plumes were transported into Beijing area continuously by south-western winds in the following hours.The mass and chemical components of the particulate matter were measured for the entire pollution process and gaseous pollutants were measured as well.Detailed data analysis shows that a)in this case of 20 June 2006 agricultural burning,transported pollution had a heavy influence on air quality nearby the burning sites,with PM₁₀ peak concentration >600μg·m^-3,but rather light influence on the northern mountain areas of Beijing where the peak concentration only reached 110μg·m^-3.The duration of the pollution was longest in the urban center.b)The pollutants transported with the plumes were PM₁₀(mainly PM₁)、CO、NO₂ and NMHC,which could be identified through the correlation factors among all pollutants measured.c)Factor analysis indicates that the contribution of the unfavorable meteorological condition to this episode in the central urban area of Beijing was greater than that of abnormal emissions from the agricultural burning.d)Nitrates,organic carbon and black carbon in PM_2.5 increased greatly in concentration,and fine particles are dominant pollutant during the pollution event.Fine organic particles may have strong influences on human health.Thus,it is strongly recommended by our study that under unfavorable weather conditions for dispersion,agricultural burning upwind of Beijing should be unconditionally banned.

• Key words：wheat stubble open burning  factor analysis  fine particles  pollution characterization

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