Air pollutants (PM2.5 and NO2) and development of adult asthma

A systematic review and meta-analysis looking at the link between air pollutants and incidence of asthma in adults.

Findings:

• 7% increased risk of developing adult asthma per 5 ug/m3 increase in particulate matter (PM2.5) exposure (pooled risk ratio 1.07 [95% CI 1.01 to 1.13], based on 9 studies)
• 11% increase in risk of developing asthma per 10 ug/m3 increase in nitrogen dioxide (NO2) (pooled risk ratio 1.11 [1.03 to 1.20], based on 9 studies)
• No significant association between ozone (O3) and developing asthma (pooled risk ratio 1.04 [0.79 to 1.36]), based on 4 studies)

Note: due to high variations between studies (heterogeneity), results should be interpreted with caution and further research is needed.