Urban roadside air pollution and human health: Real-time insights into fine particle exposure

• Spatio-temporal variation of road side PM exposure along three motorable routes was assessed. • PM concentration and RDD value differ significantly from CT to OT only on weekdays. • Variation of RDD for PM 2.5 is low for the car route and high for the bike route. • Weekday and weekend evening shows a similar kind of RDD value for bus and bike routes. High concentration of particulate matters (PM) has a negative impact on human health. Many studies focus on quantification of road side personal exposure and daily inhalation doses of fine PM < 2.5 µm (PM 2.5 ). However, personal exposure to roadside PM 2.5 is poorly documented in developing countries like India. Present research measured roadside personal PM exposure at a typical human breathing height on three pre-planned routes (bus, car, and bike) using systematic mobile monitoring. Measurements were carried out during weekday morning peak (WDM), weekday evening peak (WDE), weekend morning peak (WEM), and weekend evening peak (WEE) hours in a typical Indian town as Midnapore, west Bengal. This study also seeks to determine the significance of the difference in PM concentration and respiratory deposition doses (RDD) between town centre (CT) and town's outskirts (OT). The mean concentration of PM 2.5 on bus routes were 78 ± 10 μg/m 3 and 74 ± 18 μg/m 3 for morning and evening on weekdays. However, on weekend, the mean concentration of PM 2.5 was 77 ± 8 μg/m 3 and 69 ± 20 μg/m 3 for morning and evening peak times. The average concentrations of PM 2.5 trailed the following pattern: bus > car > bike during morning hours. Conversely, due to marketing rush hours, mean concentrations of PM 2.5 on car routes was often higher than those on bus and bike routes. RDD for bus route was always higher during weekday morning (23.2 ±3 .0 µg/h) and weekend morning (22.9 ± 2.4 µg/h) than other routes. The post-hoc ANOVA test demonstrates that PM concentration and RDD values differ considerably from CT to OT on weekdays.