Hourly concentrations of fine and coarse particulate matter and dynamic pulmonary function measurements among 4992 adult asthmatic patients in 25 Chinese cities.

The short-term associations of fine particulate matter (PM) and coarse particulate matter (PM) with pulmonary function were inconsistent and rarely evaluated by dynamic measurements. Our study aimed to investigate the associations of PM and PM with real-time pulmonary function. We conducted a longitudinal study based on dynamic pulmonary function measurements among adult asthmatic patients in 25 cities of 19 provincial regions of China from 2017 to 2020. Linear mixed-effects models combined with polynomial distributed lag models were used for statistical analysis. A total of 298,396 records among 4,992 asthmatic patients were evaluated. We found generally inverse associations of PM and PM with 16 pulmonary function indicators that were independent of gaseous pollutants. The associations occurred at lag 1 d, became the strongest at lag 4 d, and vanished a week later. PM had stronger associations than PM especially in southern China. Nationally, an interquartile increase in PM (28.0 μg/m) was significantly associated with decreases in forced expiratory volume in 1 s (FEV 41.6 mL), the ratio of FEV in forced vital capacity (1.1%), peak expiratory flow (136.9 mL/s), and forced expiratory flow at 25-75% of forced vital capacity (54.3 mL/s). We observed stronger associations in patients of male, BMI ≥ 25 kg/m, age ≥ 45 years old, and during warm seasons. In conclusion, this study provided robust evidence for impaired pulmonary function by short-term exposure to PM and PM in asthmatic patients using the largest dataset of dynamic monitoring. The associations can last for one week and PM may be more hazardous.