Abstract: In July 2022, mobile monitoring was conducted on the personal exposure concentration of PM2.5, O3 and NO2 air pollutants under two commuting modes of bus and walking in Urumqi, and the saptiotemporal changes and influencing factors of individual exposure concentration of pollutants under the two commuting modes were analyzed. The results show that: (1) In terms of temporal distribution, individual exposure concentration of PM2.5 decreases in the sequence of morning peak, off-peak, evening peak under bus mode; both individual exposure concentrations of O3 and NO2 show off-peak > evening peak > morning peak for both bus and walking modes. In morning peak, PM2.5 exposure concentration under bus mode is higher than that under walking mode, while the exposure concentrations of O3 and NO2 under walking mode are higher than those of under bus mode. In evening peak, the exposure concentrations of O3 and NO2 under walking mode are higher than those of under bus mode. In off-peak, the exposure concentration of NO2 under bus mode is higher that of under walking mode, walking O3 > bus. In terms of daily variation, the exposure concentrations of PM2.5 under bus mode is higher than that of under walk mode, while the exposure concentrations of O3 and NO2 under walk mode are higher than those of under bus model. And all the exposure concentrations of PM2.5, O3 in weekdays are higher than those in weekends for both bus and walking modes. (2) Spatially, PM2.5 concentration under foot mode is higher than that of under bus mode, while O3 and NO2 are opposite. In addition, the personal exposure concentration of pollutants in Liyushan South Road is relatively higher than that of in other road sections. Especially, the personal exposure concentration of pollutants is lower at the crossroads while comparatively higher before and after traffic lights. (3) There is a significantly positive correlation between the PM2.5 and O3 exposure concentrations and the background values for both bus and walking modes. Temperature is significantly correlated with the concentrations of PM2.5, O3, NO2 produced both in commuting modes of bus and walking. Humidity is significantly related to NO2 produced in commuting mode of buses and PM2.5, O3 and NO2 produced in commuting mode of walking. The wind speed is also significantly correlated to PM2.5, O3 and NO2 produced in commuting mode of walking, while there is a significant correlation between wind direction and PM2.5, O3, NO2 produced in commuting mode of bus and PM2.5 and O3 produced in walking mode. Finally, based on the research results in this work, , some suggestions are put forward on the residents' travel mode in order to reduce the harmful degree of air pollutant exposure to human body.

Key words: air pollutants, personal exposure, commuting mode, influencing factors