Effect modification by air pollutants
The associations of trees and allergenic trees definition 1 with higher AR and asthma were stronger in the high tertile of NO2compared to the low tertile of NO2 (Figure 1). The same holds for both definitions of allergenic trees and sensitization to aeroallergens. The associations of trees with aeroallergen sensitization and of allergenic trees definition 2 and food sensitization showed the opposite tendency. The associations of trees and allergenic trees and AR were stronger for the low ozone tertile compared to the high ozone tertile, the same was observed for the association between allergenic trees and aeroallergen sensitization (Figure E5).