北京市大气中BTEX工作日与非工作日的浓度变化

对2006年北京市大气中苯系物(BTEX)在工作日和非工作日的浓度变化进行研究.结果表明,BTEX在非工作日的平均浓度比工作日低4.8%,其中"五一"和"十一"假期BTEX的浓度分别为54%和13.2%.BTEX在非工作日浓度降低的主要原因是因为非工作日机动车使用量的减少.在工作日BTEX浓度峰值与上下班交通高峰有关,而在非工作日浓度从下午到夜间维持在一个较高浓度.BTEX各物质之间的比值在工作日和非工作日差别不大,但是各物质之间在非工作日的相关性比工作日好.苯和甲苯在工作日和非工作日都具有较好的相关性,乙苯和二甲苯之间在非工作日的相关性比工作日高.

DIFFERENCE BETWEEN WORKDAY AND NON-WORKDAY OF BTEX CONCENTRATION IN BEIJING URBAN AREA

Ambient concentrations of BTEX were analyzed to evaluate the difference between workday and non-work- day at 2006 in Beijing.The mean BTEX concentration on non-workday was 4.8% lower than on workday and much lower BTEX during Labor Day holiday and Nationality holiday,a 54% and 13.2% decreased respective- ly.The reduction of vehicle on the road during non-workday was the major contributor to the BTEX decrease. The diurnal pattern of BTEX was different between the weekday and weekend due to the difference of vehicle activity,BTEX concentration had two peak concentrations on the weekday,but on the weekend maintained high concentration from afternoon to night time.Little difference of the inter-species ratio was occurred between the workday and non-workday,but on the non-workday mutual correlations among the species was better than on the workday.Benzene and toluene had a good correlationship,while correlations were better on the non- workday between ethylbenzene and xylene.