Characteristics and determinants of personal exposure to typical air pollutants: A pilot study in Beijing and Baoding, China.

Personal exposure to fine particulate matter (PM), nitrogen oxides (NO, NO and NO), ozone (O) and sulfur dioxide (SO) was repeatedly measured among fourteen office workers in Beijing and Baoding, China in summer, autumn and winter of 2019. Time-activity patterns were simultaneously recorded. Determinants of personal air pollution exposure were investigated for each pollutant via a linear mixed effect model. The personal concentrations of PM, NO, NO and O were higher in autumn and winter than those in summer. A decreasing trend was found in the personal PM level for a typical indoor population in Beijing, indicating that particulate pollution was effectively controlled in Beijing and its surrounding area. The personal levels of PM, NO, and O were weakly correlated with those monitored at ambient stations and were lower than the respective ambient levels except for PM in summer and NO in winter. This pilot study showed that the indoor air environment, ambient pollution, traffic-related variables and temperature were significant exposure sources for office workers. Our study highlighted the significance of controlling traffic emissions and improving the workplace air quality to protect the health of office workers. More importantly, we demonstrated the feasibility of model development for personal air pollution exposure prediction.