城市道路及隧道空气中元素汞分布特征的研究

近年来随着城市交通基础建设的发展,汽车保有量的大幅增加,化石燃料的燃烧也随之增加,城市空气质量面临新的挑战。其中,大气汞污染受到越来越多的关注。文章利用Lumex RA-915和多功能汞分析仪,应用原位检测方法在隧道行车中和道路旁2 m远处,测定了城市隧道及道路周边空气中的元素汞的分布,初步研究了地面交通汞排放对周边环境中元素汞分布的特征的影响。结果表明:隧道内各点的大气汞浓度变化较小,并与通风情况有关;当隧道外自然风风速较大时,隧道内外大气中元素汞浓度均明显降低,从10~17ng/m3降低到4~8 ng/m3。地面道路旁大气元素汞的分布随汽车行驶状况、温度和昼夜变化而变化。中午大气中汞浓度较低,而傍晚较高;从白天至晚上呈上升趋势,从10.8 ng/m3和16.4 ng/m3升高到15.7 ng/m3和19.4 ng/m3;气温越高,大气中的汞浓度也越高;路口汽车怠速时汞浓度较高。因此,应加大交通排放对城市大气汞污染贡献的关注。

Distribution Feature of Atmospheric Elemental Mercury Emission of Urban Traffic and Tunnels

As the development of urban traffic construction and rapid growth of vehicle fleet,the burning of fossil fuels is growing rapidly in recent years.Urban air quality is facing a new challenge,in which mercury pollution has been aroused more and more attentions.Using Lumex RA-915+ multifunctional mercury analyzer,the distribution features of atmospheric mercury emission along urban tunnels and besides streets were assessed,while in the running vehicle through the tunnel and 2 m away from the street.Effect of elemental mercury distribution contributed by traffic emissions was preliminarily studied.Results showed that the mercury concentration inside the tunnel didn’t change so much and had a relationship with ventilation.The mercury emission inside and near both sides of tunnels would reduce a lot when ventilating situation was good,from 10~17 ng/m3 to 4~8 ng/m3.Traffic mercury emission had a relationship with traffic situation,temperature and time.Elemental mercury concentration would stay lower at noon and higher in the evening,with an escalating trend due to time of 10.8 ng/m3 and 16.4 ng/m3 up to 15.7 ng/m3 and 19.4 ng/m3.Traffic mercury concentration would get higher with higher temperature,and stay high at crossroad during the red light.Therefore,urban air pollution contributed by traffic emission should be taken more concerns.