Short-term joint exposure to air pollution & grass pollen and lung function in French school-age children: the PARIS (Pollution and Asthma Risk: an Infant Study) birth cohort

Abstract

BackgroundAs the joint effect of chemical and biological air pollution on respiratory function has been poorly studied, we aimed to investigate these associations at school age in the PARIS birth cohort.MethodsThis study included 1,063 children who participated in the health check-up (including lung function tests) at 8 years. The maximum daily concentrations of grass pollen and the maximum global air quality (ATMO) index based on four ambient air pollutants: PM10, NO2, O3 and SO2 in the Paris area during the four days prior to health check-up were determined using measurements from the Paris air quality monitoring and the French aerobiological surveillance networks. The considered exposure thresholds were ≥10 grains/m3 for grass pollen (“intermediate” allergic risk) and ≥6/10 for the ATMO index ("poor" to "very poor" air quality). Four groups of recent exposure were built by combining these two variables. The associations of these groups with respiratory parameters were studied by linear regression models adjusting for potential confounders.ResultsAmong the study population, 51% of the children were in group 1 (grass pollen <10 grains/m3, ATMO <6), 25% in group 2 (grass pollen <10 grains/m3, ATMO ≥6), 19% in group 3 (grass pollen ≥10 grains/m3, ATMO <6), and 5% in group 4 (grass pollen ≥10 grains/m3, ATMO ≥6). Compared with children in group 1, children in group 4, exposed above the thresholds for both grass pollen and air pollution, had a significant lower FEV1 (adjusted β = -69.6mL, 95% CI: -129.0 to -10.3) and FVC (adjusted β = -90.2mL, 95% CI: -161.5 to -18.8). No associations were found for children in groups 2 and 3.ConclusionThis study suggested a synergy between chemical and biological air pollutants, with deleterious effect of joint exposure to air pollution and grass pollen on lung function in children from the general population.