Abstract
OBJECTIVE: To assess the associations of different monitoring metrics for short-term exposure to ambient ozone (O(3)) with pulmonary function and airway inflammation in healthy young adults. METHODS: A total of 97 healthy young college students were recruited and followed in a panel study conducted from December 2017 to June 2018. Each participant underwent 3 follow-up visits, and lung function and fractional exhaled nitric oxide (FeNO) were measured at each visit. Ambient air pollutant concentrations were obtained from the environment monitoring station of Beijing closest to the participant residences, and meteorological data were collected from China Meteorological Data Service Center. Linear mixed-effect models were applied to assess the associations between different monitoring metrics for ambient O(3) short-term exposure with pulmonary function or airway inflammation in the healthy young adults. RESULTS: During the study period, the P(50) (P(25), P(75)) values for ambient O(3) concentration expressed as daily 1-hour maximum (O(3)-1 h max), daily maximum 8-hour average (O(3)-8 h max) and 24-hour average (O(3)-24 h avg) were 102.5 (76.8, 163.0) μg/m(3), 91.1 (68.3, 154.3) μg/m(3) and 61.6 (36.9, 81.7) μg/m(3), respectively. The different monitoring metrics for short-term exposure to ambient O(3) were significantly associated with reduced forced expiratory volume in the first second (FEV(1)) and increased FeNO. An interquartile range (IQR) increase in 6-d moving average of O(3)-1 h max (IQR=71.5 μg/m(3)) was associated with a 6.2% (95%CI: －11.8%, －0.5%) decrease in FEV(1) and a 63.3% (95%CI: 13.8%, 134.3%) increase in FeNO. An IQR increase in 7-d moving average of O(3)-8 h max (IQR=62.0 μg/m(3)) was associated with a 6.2% (95%CI: －11.6%, －0.7%) decrease in FEV(1)and a 75.5% (95%CI: 19.3%, 158.0%) increase in FeNO. An IQR increase in 5-d moving average of O(3)-24 h avg (IQR=32.9 μg/m(3)) was associated with a 3.7% (95%CI: －7.1%, －0.2%) decrease in FEV(1)and a 25.3% (95%CI: 3.6%, 51.6%) increase in FeNO. There was no significant association between the three monitoring metrics for O(3) exposure and peak expiratory flow (PEF). CONCLUSION: Short-term exposure to ambient O(3) was associated with decreased lung function and increased airway inflammation among the healthy young adults, and daily 1-hour maximum was more sensitively to the respiratory effects of O(3).