城市公交车非空调工况下CO_(2)及PM_(2.5)污染暴露特性

Characteristics of CO2 and PM_(2.5)Pollution Exposure for Urban Buses Under Non-air Conditioning Conditions

为研究城市公交车内污染物扩散特性,在2021年3月进行了大连市内某公交车非空调工况下平峰及高峰时期的内部环境现场实测,分析了气象参数及空气污染情况并分析公交车内人流量、温湿度、CO_(2)浓度以及颗粒物污染的分布规律及人员颗粒物暴露水平,采用Pearson相关和偏相关值达到方法分析影响公交车污染物的主要因素。结果表明:早高峰时段42.9%的时间车内CO_(2)浓度超过标准值最为严重,最高值达到2018 ppm,平峰和晚高峰的超标占比分别为15.6%和34.0%。不同于CO_(2)浓度,颗粒物的超标现象不显著,车内PM_(2.5)平均质量浓度12.16μg/m^(3),未超过低于国家标准二级浓度限35μg/m^(3)[16],人数变化是影响车内CO_(2)与PM_(2.5)浓度的主要因素。本文的研究为城镇居民出行规划和公交车环境调控提供了基础与依据。

In order to study the diffusion characteristics of pollutants in city buses,field measurements of the interior environment of buses under non-air conditioning in Dalian during non-peak hours and rush hours were conducted in March 2021.During the measurement,the meteorological parameters,passenger flow,temperature,relative humidity,CO_(2)concentration,particle concentration,and pollutant exposure levels were recorded and investigated.Meanwhile,Pearson correlation and partial correlation methods were used to analyze the main influencing factors of bus pollutants.The results showed that,during 42.9%of the morning peak hours,the in-vehicle CO_(2)concentration exceeded the standard value by the largest gap,with the highest value reaching 2,018 ppm,and the percentage of exceedances in the non-peak hours and evening peaks were 15.6%and 34.0%,respectively.Unlike CO_(2)concentration,the exceedance of particulate matter was not significant,and the average in-vehicle PM_(2.5)mass concentration stood at 12.16μg/m^(3),below the national standard secondary concentration limit of 35μg/m^(3)[16].Passenger flow dominantly impacted the pollutant concentration in the bus.The research in the study can provide support and basis for travel planning of resident and in-vehicle environmental control in the future.