Ultrafine particles, particle components and lung function at age 16 years: The PIAMA birth cohort study.

Background: Particulate matter (PM) air pollution exposure has been linked to lung function in adolescents, but little is known about the relevance of specific PM components and ultrafine particles (UFP).

Objectives: To investigate the associations of long-term exposure to PM elemental composition and UFP with lung function at age 16 years.

Methods: For 706 participants of a prospective Dutch birth cohort, we assessed associations of forced expiratory volume in 1 s (FEV) and forced vital capacity (FVC) at age 16 with average exposure to eight elemental components (copper, iron, potassium, nickel, sulfur, silicon, vanadium and zinc) in PM and PM, as well as UFP during the preceding years (age 13-16 years) estimated by land-use regression models. After assessing associations for each pollutant individually using linear regression models with adjustment for potential confounders, independence of associations with different pollutants was assessed in two-pollutant models with PM mass and NO, for which associations with lung function have been reported previously.

Results: We observed that for most PM elemental components higher exposure was associated with lower FEV, especially PM sulfur [e.g. adjusted difference -2.23% (95% confidence interval (CI) -3.70 to -0.74%) per interquartile range (IQR) increase in PM sulfur]. The association with PM sulfur remained after adjusting for PM mass. Negative associations of exposure to UFP with both FEV and FVC were observed [-1.06% (95% CI: -2.08 to -0.03%) and -0.65% (95% CI: -1.53 to 0.23%), respectively per IQR increase in UFP], but did not persist in two-pollutant models with NO or PM.

Conclusions: Long-term exposure to sulfur in PM may result in lower FEV at age 16. There is no evidence for an independent effect of UFP exposure.