东北地区气溶胶质量浓度分布特征

为了解东北地区的空气质量状况,2006年7月至2008年4月,选取有代表性的三个城市,用Anderson分级撞击式采样器对沈阳市、长春市和哈尔滨市进行大气气溶胶分级采样,得到逐日气溶胶质量浓度值,气溶胶平均质量浓度沈阳市哈尔滨市长春市,它们均具有明显的季节差异,冬季采暖期污染最重,以煤烟型污染为主,较细粒子所占比重高。非采暖期则以汽车尾气和自然扬尘污染为主,夏秋季节相对最清洁,春季多沙尘。春季沙尘天气与春节期间烟花爆竹造成的污染粒级分布特征不同:沙尘天气时PM10是平时的3倍多,0级和1级等粗粒级增长十分显著,6~8级细粒子增长不明显;烟花爆竹污染时PM10是平时的2倍多,以细粒子增长为主。不同天气情况气溶胶质量浓度存在明显不同,长春市和哈尔滨市清洁大气时粒级集中在8级、0级、1级和5级,且以来自自然源的较粗粒子为主,烟幕天气时PM10、PM2.5和PM1均比清洁大气时高1倍多,其质量浓度随粒径分布也有明显不同,烟幕天气主要集中在5级(1.1~2.1μm)、1级(5.8~9.0μm)和0级(9~10μm)等粒级,并以代表人为源污染的较细粒级增长为主。

Distribution characteristics of aerosol mass concentrations in Northeastern China

Mass concentrations and size distribution of aerosol particles are of current interest due to their effects on climate change,visibility and human health.Numemus studies have been conducted on it from different fields of the world.Northeastern China is the base of heavy industry in the country and PMl0 has already become the major influence factors to the urban air quality.However,there are few studies on it.Therefore,it has great scientific and practical significances to develop the researches on aerosol mass concentrations and size distribution time-space distribution characteristics in northeastern China.It also helps us to explore the sources of pollution and to take tar-geted measures to comprehensively manage atmospheric pollutants.Used with Anderson sampler,aerosol mass con-centrationb were collected from July,2006 to April,2008 in the 3 typical cities including Shcnyang,Changchun and Harbin.Results indicate that seasonal concentration difference was existed clearly.Aerosol mass concentration in Shenyang was thicker than that in Changchun,but that of Changchun was thicker than harbin's.Moreover,the most serious pollution was in winter heating period and main pollution was due to coal smoke and fine particles in it.Fine particles amount to high proportion.The pollution in non-heating period was mainly from vehicle exhaust and surface dust.Pollution was more serious in spring with strong dust storm and tIIe air was relatively clean in summer and fall.Size distribution characteristics of heavy pollution in heating winter were very different from that in sand-dust weather in spring:PM_(10) in sand-dust weather was 3 times more than usual.Coarse particles such as size classifications of 0(9-10μm)and 1(5.8-9.0 μm)grew significantly and fine particles such as size classification of 6-8(<2.5μm)did not grow apparently.PM_(10) in fireworks pollution was 2 times more than usual and mainly with relatively fine size.Aerosols mass concentrations under different weather conditions showed distinct difference :in the clean air in Changchun and Harbin City,particles size was mainly with the classifications of 8 (<0.43 μm),0(9-10μm),1(5.8-9.0μm)and 5(1.1-2.1 μm)and they were mainly focused on relative-ly coarse size from natural sources;In the weather with smoke screen,mass concentrations of PM_(10)、PM_(2.5) and PM_1 were two times over that in the clean weather,but they showed distinct distributions of mass concentration-particle size,particles size was mainly with the classifications of 5(1.1-2.1 μm),1(5.8-9.0 μm)and 0(9-10μm)and they mainly focused on relatively fine size from anthropogenic origins.