Seasonal patterns and semi-empirical modeling of in-vehicle exposure to carbon dioxide and airborne particulates in Dalian, China

Field measurements of in-vehicle carbon dioxide (CO2), PM0.3, PM1.0, PM2.5, and PM10 mass concentrations were conducted along three main roadways in Dalian, China, during spring, summer, and winter. The temperature, relative humidity, and air pressure both inside and outside the vehicle were recorded simultaneously. A correlation analysis was used to evaluate the dominant factors influencing the CO2 and particle mass concentrations. Two semi-empirical pollutant models describing the in-vehicle CO2 and particle mass concentrations were established and validated using field data. The in-vehicle CO2 concentration exceeded the 1000 ppm limit during the majority of the period. Among the different cases, the averaged in-vehicle CO2 concentration under international air conditioning (AC) conditions was highest at 2977.9 +/- 914.1-3866.7 +/- 1035.9 ppm. In contrast, the in-vehicle PM2.5 mass concentration did not reveal significant variation among the different cases. These results, especially those of semi-empirical pollutant dispersion models, could predict in-vehicle pollutant exposure levels, providing useful guidance for optimized ventilation control in vehicles.

Automated summary

Field measurements were conducted to investigate the in-vehicle carbon dioxide (CO2) and particulate matter (PM) concentrations in Dalian, China. Two semi-empirical pollutant models were established to predict the pollutant exposure levels inside vehicles. The study found that in-vehicle CO2 concentration exceeded the limit in most cases, while the PM2.5 concentration showed less variation. These findings provide useful guidance for optimized ventilation control in vehicles.