Background: novel multipollutant approaches could help to understand the health effects of air pollution.

Aim: to assess the relationship of long-term exposure with chronic obstructive pulmonary disease (COPD) and asthma prevalence in an Italian multicenter study.

Methods: 14420 adults living in 6 Italian cities (Ancona, Pavia, Pisa, Sassari, Turin, Verona) were investigated in 2005-11 within 11 different study cohorts. Questionnaire information about risk factors and health outcomes was collected. Mean annual PM₁₀, PM_2.5, NO₂ and mean summer O₃ concentrations were estimated at the residential addresses (1-km resolution) for the period 2013-15. The associations between the pollutants and COPD and asthma symptoms/diagnosis were assessed using principal component logistic regression models (multipollutant model). All the models were adjusted for age, sex, education level, smoking habits, season of interview, climatic index; they included a random intercept for the cohorts.

Results: the three-year means (± standard deviation) were: 20.3±6.8 µg/m³ for PM_2.5, 29.2±7.0 µg/m³ for PM₁₀, 28.0±11.2 µg/m³ for NO₂, 70.9±4.3 µg/m³ for O₃. COPD and asthma were related to PM₁₀ (odds ratio - OR - 1.13, confidence intervals - 95% CI - 1.02-1.25, for 10 µg/m³ increase, and OR 1.23, 95% CI 1.08-1.40, respectively), PM_2.5 (OR 1.14, 95% CI 1.01-1.28 and OR 1.26, 95% CI 1.08-1.47, respectively) and NO₂ (OR 1.06, 95% CI 1.03-1.10 and OR 1.07, 95% CI 1.03-1.12, respectively). No significant association was found for O₃.

Conclusions: new information about the health effects of air pollution on COPD and asthma in adults emerged by applying innovative methods for multipollutant exposure assessment.