Ambient fine particulate matter (PM) has been associated with impaired lung function, but the effect of temperature on lung function and the potential interaction effect between PM and temperature remain uncertain. To estimate the short-term effects of PM2.5 combined with temperature on lung function, we measured the daily peak expiratory flow (PEF) in a panel of 37 healthy college students in four different seasons. Meanwhile, we also monitored daily concentrations of indoor and outdoor PM2.5 (particulate matter with an aerodynamic diameter ≤2.5 μm), ambient temperature and relative humidity of the study area, where the study participants lived and attended school. Associations of air pollutants and temperature with lung function were assessed by generalized estimating equations (GEEs). A 10 μg/m3 increase of indoor PM2.5 was associated with a change of −2.09 L/min in evening PEF (95%CI: −3.73 L/min–−0.51 L/min) after adjusting for season, height, gender, temperature and relative humidity. The changes of −2.17 L/min (95%CI: −3.81 L/min– −0.52 L/min) and −2.18 L/min (95%CI: −3.96 L/min–−0.41 L/min) in evening PEF were also observed after adjusting for outdoor SO2 and NO2 measured by Environmental Monitoring Center 3 kilometers away, respectively. An increase in ambient temperature was found to be associated with a decrease in lung function and our results revealed a small but significant antagonistic interactive effect between PM2.5 and temperature. Our findings suggest that ambient PM2.5 has an acute adverse effect on lung function in young healthy adults, and that temperature also plays an important role.

Objectives: To explore the health effects of indoor/outdoor carbonaceous compositions in PM2.5 on pulmonary function among healthy students living in the local university campus. Methods: Daily peak expiratory flow (PEF) and forced expiratory volume in 1 second (FEV1) were measured among 37 healthy students in the morning and evening for four two-week periods. Concurrent concentrations of indoor and outdoor PM2.5 (particulate matter with an aerodynamic diameter ≤ 2.5m), carbonaceous components in PM2.5, ambient temperature, and relative humidity in the study area were also obtained. Mixed-effects model was applied to evaluate the associations between carbonaceous components and lung function. Different lags for the carbonaceous components were investigated. Results: In single-pollutant model, a 10 g/m3 increase of indoor and outdoor EC (elemental carbon) associated with −3.93 (95%CI: −6.89, −0.97) L/min and −3.21 (95%CI: −5.67, −0.75) L/min change in evening PEF at lag 0 day, respectively. Also, a 10 g/m3 increase of indoor and outdoor POC (primary organic carbon) concentration was significantly associated with −5.82 (95%CI: −10.82, −0.81) L/min and −7.32 (95%CI: −12.93, −1.71) L/min change of evening PEF at lag 0 day. After adjusting total mass of PM2.5, indoor EC consistently had a significant adverse impact on evening PEF and FEV1 at lag3 day and a cumulative effect at lag0-3 day. Conclusions: This study suggests that carbonaceous components in PM2.5 indeed have impacts on pulmonary function among healthy young adults especially on evening PEF. Thus, the local mitigation strategies on pollution are needed.