Long-term PM_2.5 exposure impairs lung growth and increases airway inflammation in Taiwanese school children

Prolonged exposure to particulate matter with aerodynamic diameter <2.5 µm (PM_2.5) may aggravate asthma, impair lung development and increase airway inflammation. This study investigated the impact of long-term PM_2.5 exposure on respiratory health, lung function growth and fractional exhaled nitric oxide (F _ENO) in a large longitudinal cohort of school children.

A total of 6120 elementary school children residing in townships near coal-fired power plants in Taiwan were prospectively enrolled from 2016 to 2018. Baseline and follow-up data on asthmatic symptoms, spirometry, F _ENO and environmental factors were collected. Annual PM_2.5 exposure was estimated using land-use regression models based on school and home addresses, and associations were adjusted for SO₂ and NO₂.

The final analysis included 5364 children and revealed that a 1 μg·m^-3 increase in annual PM_2.5 exposure was associated with higher odds of current wheezing (OR 1.07), "ever" wheeze (OR 1.03), diagnosed asthma (OR 1.03) and exercise-induced wheeze (OR 1.04) (p<0.05). Each unit increase in PM_2.5 exposure was associated with a decrease of 7 mL in forced expiratory volume in 1 s (FEV₁), 5 mL in forced vital capacity (FVC) and a 0.479-ppb rise in F _ENO after adjusting for potential confounders (p<0.05). Among 207 new-onset wheezing patients, increased PM_2.5 exposure significantly decreased FEV₁ by 13 mL and FVC by 15 mL, while increasing F _ENO levels by 0.847 ppb (p<0.05).

Long-term PM_2.5 exposure significantly increases the risk of asthma symptoms, impedes lung growth and triggers airway inflammation, particularly affecting children with new-onset wheezing in community settings.