河北张家口市大气污染观测研究

冀北重镇张家口,全年干旱少雨风沙大,自然生态环境极其脆弱,但近年来工业发展极为迅速.为了解张家口市大气污染物浓度水平及季节变化,2009年12月1日～2010年11月30日,利用自动在线仪器对张家口市区大气典型污染物NOx、SO2、O3和PM10进行了连续观测研究.结果表明,张家口市首要污染物为可吸入颗粒物(PM10),年均质量浓度达(137±105)μg.m-3.NO、NO2、SO2和O3年均质量浓度分别为:(8±13)、(30±15)、(19±26)和(54±35)μg.m-3.NOx和SO2质量浓度冬季最高,分别达(51±35)μg.m-3和(42±29)μg.m-3;夏季最低,分别为(28±8)μg.m-3和(4±3)μg.m-3.O3质量浓度夏季最高,达(92±40)μg.m-3,最高小时均值可达271μg.m-3;冬季最低,为(34±20)μg.m-3.PM10质量浓度春季最高,达(144±131)μg.m-3;冬季最低,为(130±129)μg.m-3,但季节变化不明显.依照国家二级标准PM10日均值超标率为28%.季节统计日变化显示NOx和PM10为早晚双峰型,SO2为午间单峰型,O3为午后单峰型.张家口市区大气污染日变化受到交通源显著影响,气态污染物冬季受取暖燃煤显著影响.夏季东南气流对张家口O3有输送作用,自西北的沙尘及局地扬尘(浮尘)对张家口PM10影响显著,并对华北平原区域造成一定影响.

Observation and Analysis of Air Pollution in Zhangjiakou, Hebei

Zhangjiakou is an important city in the north of Hebei province with rapidly developing industry in recent years,which has little precipitation and a very fragile ecological environment.The observation of atmospheric pollutants was done from December 2009 to November 2010 to illuminate the air pollution situation.The results showed that the annual mean concentration of PM10,the primary pollutant,reached(137±105) μg·m-3,and those of NO,NO2,SO2 and O3 were(8±13),(30±15),(19±26) and(54±35) μg·m-3,respectively;The seasonal mean concentrations of NOx and SO2 were highest in winter,with values of(51±35) μg·m-3 and(42±29) μg·m-3,respectively,and lowest in summer,only(28±8) and(4±3) μg·m-3,respectively.For O3,the highest value was recorded in summer,with seasonal mean of(92±40) μg·m-3 and the highest daily maximum hourly concentration of 271 μg·m-3,whereas the lowest seasonal mean value of(34±20) μg·m-3 was obtained in winter.The highest seasonal average PM10 was measured in spring,reaching(144±131) μg·m-3,and lowest in winter,with a value of(130±129) μg·m-3,indicating little seasonal variation of PM10.The rate that PM10 exceeded the National Ambient Air Quality Standard Ⅱ was 28%.The diurnal variations of pollutants in four seasons showed that the average diurnal variations of NOx and PM10 were similar with peaking in early morning and evening,while the peak of SO2 and O3appeared at noon and in the afternoon,respectively.The diurnal variation of air pollutants was significantly affected by the traffic,and the seasonal variation of gas pollutants was significantly affected by coal-fired heating in winter.In summer,the air masses from southeast regions could transport O3 and its precursors to Zhangjiakou.Dust carried by northwestern air masses and local dust with strong winds greatly affected PM10 in Zhangjiakou,and North China Plain was also affected in some degree.