Associations between short-term exposure to ambient air pollution and lung function in adults

Evidence of the acute effects of high-level air pollution on small airway function and systemic inflammation in adults is scarce.

To examined the associations of short-term (i.e., daily) exposure to multiple air pollutants with lung function and inflammatory markers.

We assessed short-term (daily) effects of air pollutants, including particulate matter with aerodynamic diameter less than 2.5 μm (PM_2.5) and 10 μm (PM₁₀), nitrogen dioxide (NO₂), sulfur dioxide (SO₂) and carbon monoxide (CO), on lung function and peripheral immune cell counts over various lag times using generalized linear regression models.

A total of 4764 adults were included from the general community-dwelling population in Shanghai, China. Exposure to air pollutants and lung function were negatively correlated. Decline in FEF between 25% and 75% of vital capacity (FEF_25-75%) were found associated with PM_2.5, SO₂, and CO, and decline in forced expiratory volume in 3 s (FEV₃) to forced vital capacity (FVC) ratio were associated with all examined pollutants, indicating obstruction in small airways. Obstructed airflow in large and middle airways as indicated by decline in FEV₁/FVC were also associated with all pollutants. In subgroup analysis, significant negative associations between the five pollutants and SAD parameters were found only in males but not in females. The difference in the associations of SO₂ with FEF_75% between males and females achieved statistical significance. Additionally, all examined pollutants were significantly associated with lower peripheral neutrophil count.

Acute exposure to air pollutants were associated with airflow-limitation. Both small airways and proximal airways were affected. Acute exposure to air pollutants were accompanied with a lower neutrophil count.