天津市典型市区隧道机动车黑碳污染排放特征与健康风险评价

Pollution characteristics and health risks assessment of black carbon from vehicles emissions in typical urban tunnel of Tianjin

在天津五经路隧道开展机动车排放的黑碳(Black carbon,BC)浓度特征及其对人群健康影响研究,对机动车排放BC的浓度水平与变化特征进行分析,同时计算获得汽油车和柴油车的BC排放因子,并通过美国环保局(US EPA)的健康风险评价模型对BC的健康风险进行评价.结果表明,隧道入口和出口处BC质量浓度均值分别为(2.21±0.74)和(4.02±1.56)μg·m^(-3).隧道内BC累计质量浓度在凌晨、早高峰和晚高峰3个时间段上存在极大值点,说明交通道路BC浓度变化与车辆类型和车流量变化密切相关.隧道中机动车BC综合排放因子为(2.62±0.60)mg·km^(-1)·辆^(-1),基于多元线性回归方法计算获得隧道内汽油车和柴油车的BC排放因子分别为(1.51±0.24)和(56.9±15.2)mg·km^(-1)·辆^(-1).健康风险评价结果表明,对于儿童和成人,隧道进口与出口处BC的非致癌风险指数均小于1,非致癌风险在安全范围之内.但BC对成人和儿童的致癌风险均超过EPA推荐的可接受风险阈值(10^(-4)~10^(-6)),很大可能会对暴露人群造成致癌风险.

In order to study pollution characteristics and health risk of black carbon(BC)from vehicle emissions,a tunnel test was conducted in the Wujing Road tunnel of Tianjin,China.The concentration level and change characteristics of vehicle emission BC were analyzed.The BC emission factors of gasoline vehicles and diesel vehicles were studied.The health risk of BC was assessed by using the health risk assessment method(US EPA).The results showed that the mean values of BC mass concentration at the entrance and exit of the tunnel were(2.21±0.74)and(4.02±1.56)μg·m^(-3),respectively.The cumulative concentration of BC in the tunnel has a maximum value in the early morning,morning peak and evening peak time periods,indicating that the BC concentration on the traffic road is closely related to the change of vehicle types and traffic volume.The BC comprehensive emission factor of motor vehicles in the tunnel was(2.62±0.60)mg·km^(-1)·vehicle^(-1).Based on the multiple linear regression method,the BC emission factors of gasoline and diesel vehicles in the tunnel were(1.51±0.24)mg·km^(-1)·vehicle^(-1)and(56.9±15.2)mg·km^(-1)·vehicle^(-1).The health risk assessment results showed that the non-carcinogenic risk index of BC at the entrance and exit of the tunnel was less than 1 for children and adults,which was within safe limits.However,the carcinogenic risk of BC to adults and children exceeds the acceptable risk threshold recommended by EPA(10^(-4)~10^(-6)),and it is likely to cause carcinogenic risk to exposed people.