OBJECTIVETo evaluate the acute effects of indoor and outdoor particulate matter on lung function and respiratory symptoms of college students in winter.

METHODSA panel of 37 college students aged 19-21 in Wuhan were included and the investigation was carried out from 12/23/2009 to 01/05/2010. Daily morning/evening forced expiratory volume in one second (FEV1) and respiratory symptoms (cough, phlegm and runny) were measured and reported by subjects, respectively. Meanwhile, daily data of indoors and outdoors PM10, PM2.5, temperature, and relative humidity were collected. Generalized Estimating Equations (GEEs) were used to estimate the association between particulate matters exposure and respiratory symptoms and FEV1).

RESULTSAverage daily concentrations of indoor, outdoor PM2.5 during the study period were (110.6 ± 42.3), (143.5 ± 51.2) µg/m³, (148.2 ± 43.2) and (239.1 ± 71.3) µg/m³ for indoor, outdoor PM10, respectively. Outdoor exposure to PM2.5 on lag 0 had little effect on evening FEV1). However, researchers observed a significant lagging effect (lag 1 d) and accumulative effect (lag 0-1 d and lag 0-2 d). A rise in the PM2.5 concentration of 10 µg/m³ resulted in the change of evening FEV1) of -0.28% (95% CI: -0.52%, -0.03%), -0.45% (95% CI: -0.81%, -0.08%) and -0.63% (95% CI: -1.15%, -0.11%), respectively. For respiratory symptoms of coughing up phlegm, 10 mg/m³ increase of indoor/outdoor PM2.5 concentration were associated with odds ratio of 1.18 (95% CI: 1.02-1.36) and 1.08 (95% CI: 0.97-1.19), respectively. Moreover, risk of coughing up phlegm increased with lagging time, and accumulative time of indoor and outdoor PM2.5 and PM10.

CONCLUSIONOur study suggested that short-term exposure to particulate matters in winter was significantly associated with acute changes of respiratory symptoms and FEV1) of college students in Wuhan. Moreover, the effects of particulate matters tended to be larger as the increase of lagged and accumulative days.