People often travel a long distance on highways to the nearest city for professional/business activities. However, relatively few publications on passenger exposure to pollutants on highways in India or elsewhere are available. The aim of this study was to examine the contribution of different travel modes to passengers' pollutant exposure for a long distance travel on a national highway in India. We measured PM_2.5 and CO exposure levels of the passengers over 200 km on a national highway using two portable air monitors, EVM-7 and EPAM-5000. Personal concentration exposures and per min-, per hour-, per trip- and round trip mass exposures for three travel modes were calculated for 9 trips. Association between pollutants and weather variables were evaluated using levels Spearman correlation. ANOVA was carried out to evaluate the influence of travel mode, the timing of trips, temperature and RH on personal exposures. On an average, PM_2.5 personal concentration exposure levels were highest in the car (85.41 ± 61.85 μg m^− 3), followed by the bus (75.08 ± 55.39 μg m^− 3) and lowest in the car (ac) (54.43 ± 34.09 μg m^− 3). In contrast, CO personal exposure was highest in the car (ac) (1.81 ± 1.3 ppm). Travel mode explained the highest variability for CO (18.1%), CO₂ (9.9%), PM_2.5 (1.2%) exposures. In-city mass exposures were higher than trip averages; PM_2.5:1.21–1.22, 1.13–1.19 and 1.03–1.28 times; CO: 1.20–1.57, 1.37–2.10 and 1.76–2.22 times for bus, car and car (ac) respectively. Traveling by car (ac) results in the lowest PM_2.5 exposures, although it exposes the passenger to high CO level. Avoiding national highways passing through cities can reduce up to 25% PM_2.5 and 50% CO mass exposures. This information can be useful for increasing environmental awareness among the passengers and for framing better pollution control strategies on highways.

人们经常在高速公路上长途跋涉到最近的城市进行专业/商业活动。但是，关于印度或其他地方的公路上乘客接触污染物的出版物很少。这项研究的目的是检验在印度国道上长途旅行时，不同出行方式对乘客污染物暴露的影响。我们测量了PM _2.5使用两个便携式空气监测仪EVM-7和EPAM-5000，在国家高速公路上行驶200公里以上的乘客的CO暴露水平。对于9次旅行，计算了三种旅行模式下的个人专注力暴露以及每分钟，每小时，每次旅行和往返的质量暴露。使用Spearman相关性水平评估污染物与天气变量之间的关联。进行方差分析以评估出行方式，出行时间，温度和相对湿度对个人暴露的影响。平均而言，PM _2.5的个人浓度暴露水平在汽车中最高（85.41±61.85μgm ^{− 3}），其次是公共汽车（75.08±55.39μgm ^{− 3}），在汽车中最低（ac）（54.43±34.09）微克米^-3）。相比之下，汽车中的一氧化碳个人暴露量最高（ac）（1.81±1.3 ppm）。出行模式解释了CO（18.1％），CO ₂（9.9％），PM _2.5（1.2％）暴露的最大变异性。城市内的大众暴露水平高于出行平均水平；PM _2.5：1.21-1.22、1.13-1.19和1.03-1.28倍；CO：公共汽车，小汽车和小汽车（ac）分别为1.20–1.57、1.37–2.10和1.76–2.22倍。乘汽车旅行（ac）可使PM _2.5暴露最低，尽管这会使旅客暴露在高CO水平下。避免国道通过城市最多可减少25％的PM _2.5和50％的一氧化碳暴露量。这些信息对于提高乘客的环保意识以及为高速公路制定更好的污染控制策略很有用。