PURPOSE OF REVIEW: Studies over the last 2 years have added important new information on the relationship between air pollution and asthma incidence and severity.
RECENT FINDINGS: Outdoor air pollution has been associated with asthma exacerbations, including emergency department visits and hospitalizations, as well as with the onset of asthma. Possible mechanisms mediating both incidence and severity effects include the induction of oxidative stress, and/or allergic sensitization, as well as increased susceptibility to viral infections. Some of these mechanisms may be occurring in utero including epigenetic changes that may increase risk for development of asthma. Factors related to increased susceptibility for air pollution-related asthma severity include age, season and genetic polymorphisms related to antioxidant enzymes.
SUMMARY: Ambient pollution levels may be associated with both asthma incidence and severity. Susceptibility to air pollution may be higher in children with genetic polymorphisms related to the ‘oxidant stress pathways’. Potential interventions for susceptible children at risk for asthma development and/or severity include decreased exposure on high air pollution days, especially in the summer months, and antioxidant supplementation. On the population level, changes in school and home zoning to increase distance from busy roadways may help reduce both asthma incidence and severity.