Short-term effects of real-time individual fine particulate matter exposure on lung function: a panel study in Zhuhai, China

Fine particulate matter (PM2.5) is still the primary air pollutant in most Chinese cities and its adverse effects on lung function have been widely reported. However, short-term effects of individual exposure to PM2.5 on pulmonary expiration flow indices remain largely unknown. In this study, we examined the short-term effects of real-time individual exposure to PM2.5 on lung function in a panel of 115 healthy adults. We measured individual real-time PM2.5 exposure and lung function. Environmental PM2.5 concentrations in the same period were collected from the nearest monitoring station. Generalized linear model was used to assess the effects of individual PM2.5 exposure on lung function after adjusting for potential confounders. Individual PM2.5 exposure ranged from 18.5 to 42.4 mu g/m(3) with fluctuations over time and ambient PM2.5 concentrations presented a moderate trend of fluctuation at the same day. Except forced expiratory volume in 1 s (FEV1) decline related to 2-h moving average PM2.5 exposure, no significant associations between individual PM2.5 exposure and other volume indices including forced vital capacity (FVC) and FEV1/FVC ratio were observed. The adverse effects of individual PM2.5 exposure on pulmonary expiration flow indices including peak expiratory flow (PEF), maximal mid-expiratory flow (MMF) and forced expiratory flow at 50%, and 75% of vital capacity (FEF50% and FEF75%) were observed to be strongest at 2 moving average hours and could last for 24 h. Stratified analysis showed greater and longer effects among participants who were aged over 40 years, males, or smokers. These findings suggested that individual PM2.5 exposure was significantly associated with altered lung function, especially with pulmonary expiration flow indices decline, which was strongest at 2 moving average hours and could last for 24 h.