Indoor ozone and particulate matter modify the association between airborne endotoxin and schoolchildren's lung function

Background: To date, the effect of household airborne pollutants on the association between airborne endotoxin and lung function of schoolchildren is unknown. Objectives: The objective of this study is to evaluate whether indoor air pollutants such as carbon monoxide (CO), carbon dioxide (CO₂), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), ozone (O₃), particulate matter with aerodynamic diameter <10 and 2.5 μm (PM₁₀, PM_2.5) can modify the association between airborne endotoxin and school children's lung function in a heavy industrial city in Taiwan. Methods: We recruited 120 elementary school-age children in Kaohsiung City, Taiwan. Aerosol samples were collected on a filter membrane for 24 h period and then analyzed for endotoxin. Air pollutants were measured for 24 h in living rooms while school children's lung function was measured. The modification of air pollutants on the relationship between airborne endotoxin and children's lung function was estimated after adjusting the gender, age, height, weight, and case-control status. Results: We found that both O₃ and PM₁₀ concentrations significantly modified the relationships between airborne endotoxin and school children's lung function. Among children living in homes with O₃ ≥ 0.01 ppm or PM₁₀ ≥ 62 μg/m³, airborne endotoxin was negatively associated with lung functions, whereas among those living in homes with O₃ < 0.01 ppm or PM₁₀ < 62 μg/m³, airborne endotoxin was positively associated with lung functions. Conclusions: The indoor air pollutant concentration of O₃ and PM₁₀ modifies the association between airborne endotoxin and school children's lung function.