【作者】 樊文雁；

【导师】 王式功； 孙扬；

【作者基本信息】 兰州大学 ， 气象学， 2008， 硕士

【摘要】 为了系统研究北京大气污染特征,探索京津冀城市群区域污染形成的原因,本文利用中科院大气物理研究所325m铁塔2005-2006年PM_2.5和PM₁₀和2004.8-2007.8大气O₃、NO、NO₂、NOx的垂直分层观测资料及2007年夏季中国科学院建立的北京地区大气环境观测网实测数据,结合北京及7周边城市2004-2006年API指数和部分时段的气温、气压、露点温度、能见度、风速风向等资料,对北京及周边地区近年来的大气污染现状进行分析讨论研究。结果表明:（1）北京及其周边城市首要污染物均是可吸入颗粒物,且污染严重。2006年北京PM₁₀年平均浓度为162.1±92.3μg·m^-3,PM_2.5年平均浓度为77.4±53.7μg·m^-3,PM_2.5/PM₁₀的年平均比值为50.5%。春季受沙尘天气影响,3,4月PM₁₀平均浓度高达215.6±125.9μg·m^-3;北京市夏季细粒子污染也十分严重,8月份PM_2.5浓度在距地面8、120、240m上依次分别为66.8±40.3、64.4±40.7、58.8±39.3μg·m^-3,均超过WHO阈值1倍以上,表现为厚厚的霾层笼罩在北京的城市上空。（2）8月份细粒子在垂直上分布有明显的分层现象,240m的浓度低于其它两层,且呈现双峰形的日变化,低层的日变化呈现单峰形变化。15∶00,由于午后湍流运动和对流发展,将近地层的污染物向上输送,240m的浓度高于其它两层。（3）2005-2006年,北京大气氮氧化物年均值分别为66.5±71.4、48.6±42.1ppb;臭氧的年均值分别为19.0±23.7和18.3±22.3ppb,而2007年前8个月臭氧平均浓度达到了24.0±26.8ppb,和前三年相比有上升迹象;奥运时段的8月份,北京2004-2006年大气臭氧浓度依次分别为22.4±21.9、29.7±31.6、27.7±29.6ppb,且在垂直梯度上存在明显高污染“层结”。2007年8月,8m臭氧夜间浓度最低约为10ppb,120m夜间臭氧浓度约为20ppb,而280m约为30ppb,表现为夜间臭氧较高层贮存,造成对下一天臭氧白天高值的明显影响。（4）2007年8月17-20日北京车辆限行期间,NO日平均为5.1±9.3ppb,NO₂日平均为26.7±13.5ppb,与前后非限行期相比,NO约下降43.9%,NO₂下降约25.1%;但限行时段O₃日平均为41.0±31.4ppb,高出前后非限行期10.8ppb,上升约36%;由于静稳天气有利于污染物积累,细粒子上升显著,日平均增长量约为11.5μg·m^-3,但车辆限行在一定程度上缓解了可吸入颗粒物的上升。（5）2007年夏秋季节,北京325米气象塔8、80、240m平台梯度观测结果表明,雾、霾、晴三种典型天气状况大气细粒子质量浓度垂直分布各有其特点,11.5-6日的雾天低层浓度明显偏高,6日从低到高3层PM_2.5日均值分别为352.6±79.3、224.7±69.0、214.8±32.8μg·m^-3;霾天的8.19-20日细粒子上下混合均匀,19日从低到高3层PM_2.5浓度都在89.8±29.3、88.9±29.8、90.0±31.7μg·m^-3:8.22-23日晴天细粒子昼夜变化明显,夜间在80m高度出现明显分层,23日80m以下平均值为32.6±13.1μg·m^-3,240m平均值为27.4±13.5μg·m^-3。雾天细粒子主要形成于局地,霾天细粒子污染表现为时空分布十分均匀的城市群区域污染特征且污染物积累;连续晴天则存在明显的细粒子清除。更多还原

【Abstract】 We use the mass concentration of PM_2.5and M₁₀,which were observed on 8,80, 240m platform in 325m Beijing meteorological tower from 2005 to 2006,the cubage concentration of O₃,NO,NO₂、NOx,which were observed on 8,80,240 m platform in 325m Beijing meteorological tower from August,2004 to August 2007;and the PM_2.5,M₁₀,O₃,NO,NO₂,NOx observations of Beijing,Tianjin,Tangshan in August 2007,which camme from the Beijing Area atmosphere pollution observe net,add the API of Beijing,Tianjin,Tangshan,Datong,Taiyuan,Chifeng,Jinan,Shijiaxzhuang from 2004 to 2006,the air temperature,air pressure,dew point,visibility,wind,to research the local pollution of Beijing and the area pollution of Beijing surrounding area.The results are as follows:（1）The primary contamination of Beijing Area is PM₁₀,it is more serious than the pollution,caused by sulfur dioxide.In 2006 the Beijing aergsol pollution is serious, the annual average concentraation of PM2.5 and M₁₀is 162.1±92.3,77.4±53.7μg·m^-3 respectively.The annual average ratios of PM_2.5to PM₁₀is 50.5%,the PM_2.5mass is an half of PM₁₀mass.Primrose season the PM₁₀concentration,goes up 215.6±125.9μg·m^-3caused by dust storm.PM_2.5pollution is serious.in summer,from. 8,120 to 240m the mensal average PM_2.5concentration were.66.8±40.3,64.4±40.7 and 58.8±39.3μg·m^-3respectively,they all overstep WHO range more than one multiple,show a very thick haze layer structure oyercast the top of Beijing city.（2）The concentrations of PM_2.5show a very distinct variation.There is an obvious vertical layer,structure in August.The concentrations of PM_2.5in 240 meter lower than the concentrations in 8,80 meter,and it show a very clear cycle with two peaks.The diurnal variations of the PM_2.5concentration in the low layers（8 and 80, meter）show a very.clear cycle with one peak.The pollutions is transported from ground to the high layer by the air onflow and air convection at afternoon,so the concentrations of PM_2.5in 240-meter layer is higher than.the concentrations in the. other layers at 15:00.（3）During the gas contamination of Beijing,NOx pollution is light,the annual average concentration of NOx in 2005 and 2006 is 66.5±71.4,48.6±42.1 ppb respectively,the NOx concentration decrease year after year.But ozone pollution increase obviously,the annual average concentration of ozone in 2005 and 2006 is 9.3±23.7,18.3±22.3 ppb respectively,and the average concentration of ozone from January to August in 2007 is 24.0±26.8ppb.Ozone pollution in August is very distinct. In August of 2005,2006,2007,the ozone mensal average concentration is 22.4±21.9, 29.7±31.6 and 27.7±29.6 ppb respectively.There was an obvious vertical layer structure of Ozone,especially at night.From 8-280m the ozone concentration at night arel0,20,and 30ppb.The Ozone deposit at night,and make the ozone concentration increase in the next day.（4）In the "car drive selectivity" days,（from 17th to 20th of August in 2007）,the daily average NO concentration is 5.1±9.3ppb,the daily average NO₂ concentration is 26.7±13.5 ppb,they are lower than the average concentration of the other days in August,reduce rate of NO and NO₂ are 43.9%,25.1%respectively.The daily average ozone concentration is 41.0±31.4 ppb,overtop 10.8 ppb to the average concentration of the other days in August,increase rate is 36%.As a result of the weather concentration of PM2.5,is increased 11.5μg·m^-3day-by-day.The "car drive selectivity" reduces the car in the road,and slower the PM_2.5increased extent.（5）PM_2.5are installed on 8,80,240 m platform in 325 m Beijing meteorological tower during summer and autumn in 2007.Results show that there is an obvious vertical distribution of PM_2.5concentration in diffreent weather condition.There is an obvious vertical distribution of PM_2.5concentration in diffreent weather condition.During the fog period（11.5-6）,from 8-240m the daily average PM_2.5 concentration are 352.6±79.3,224.7±69.0 and 214.8±32.8μg·m^-3respectively.On 6th of Nov.,the PM_2.5concentration altere obvious.In haze weather condition（8.19-20）, PM_2.5concentration mix uniformly,the daily average concentration in 8,80,240 m are 89.8±29.3,88.9±29.8 and 90.0±31.7μg·m^-3on 19th of August.During the sunshine condition（8.22-23）,The concentrations of PM_2.5show a very distinct diural variation.There is an obvious vertical layer structure,especially at night.On 23rd of Aug.,8-80 m the aerosol mix uniformly the daily average PM_2.5concentration is 32.6±13.1μg·m^-3,and the concentration of 240 m is 27.4±13.5μg·m^-3.The particle of fog are mainly from local sources.However,the particle of haze are maily from regional sources,and show increased setrend of concentration accumulated.There is a elimination process of PM_2.5during the continuously fine days.更多还原