北京机动车限行期间苯和甲苯的DOAS测量

基于差分光学吸收光谱(DOAS)技术在北京机动车限行期间8月7日到28日对苯和甲苯进行连续监测，获取苯、甲苯的变化特征，分析交通排放苯、甲苯和车流量关系. 监测结果表明，整个交通管制期间，监测点苯与甲苯相关系数为0.8，且二者比值为0.43～0.50，充分证明苯系物具有同源性. 限车时段苯的浓度下降11.4%，甲苯下降12.8%，而车流量下降11.8%，因此苯和甲苯是北京机动车排放的主要来源.

Benzene and Toluene Levels Measured with DOAS During Vehicular Restrictions in Beijing

Measurements of atmospheric benzene and toluene were carried out continuously using dif-ferential optical absorption spectroscopy from August 7 to August 28 in Beijing during the period of vehicular restrictions. The correlations between traffic flows and totals of benzene and toluene were studied during the period of vehicular traffic restrictions from August 17 to August 20 and non-traffic restrictions on August 16 and August 21. The correlation coef-ficient was 0.8 between benzene and toluene. And the calculated daily mean value ratios of benzene to toluene were 0.43-0.50. During the period of vehicular restrictions, traffic flows were reduced about 11.8% and the levels of benzene and toluene were reduced by 11.4% and 12.8%, respectively. The vehicle emissions were recognized as the major sources for atmospheric benzene and toluene in Beijing.