Influence of PM₁ and PM_2.5 on lung function parameters in healthy schoolchildren-a panel study

To evaluate lung function responses to short-term indoor PM₁ and PM_2.5 concentrations, we conducted a panel study of healthy schoolchildren aged 13-14 years. The following lung function parameters FVC, FEV₁, PEF, and mid expiratory flows MEF₂₅, MEF₅₀, and MEF₇₅ were measured in 141 schoolchildren of the secondary school in Wroclaw, Poland in years 2009-2010. On days when spirometry tests were conducted, simultaneously, PM₁ and PM_2.5 samples were collected inside the school premises. Information about differentiating factors for children including smoking parents, sex, living close to busy streets, dust, mold, and pollen allergies were collected by means of questionnaires. To account for repeated measurements, the method of generalized estimating equations (GEE) was used. The GEE models for the entire group of children revealed the adverse effects (p < 0.05) of PM₁ and PM_2.5. Small differences in effects estimates per interquartile range (IQR) of PM₁ and PM_2.5 on MEF₂₅ (5.1 and 4.8 %), MEF₅₀ (3.7 and 3.9 %), MEF₇₅ (3.5 and 3.6 %) and FEV₁ (1.3 and 1.0 %) imply that PM₁ was likely the component of PM_2.5 that might have a principal health effect on these lung function parameters. However, the reduction of FVC and PEF per IQR for PM_2.5 (2.1 and 5.2 %, respectively) was higher than for PM₁ (1.0 and 4.4 %, respectively). Adjustment for potential confounders did not change the unadjusted analysis.