1. By Cesar E. Lebron

2. Bronx County has some of the highest rates of asthma in the United States. Rates of death from asthma in the Bronx are about three times higher than the national average. Hospitalization rates are about five times higher

7. The association between air pollution and asthma remains poorly understood. Since exposure is always to a mix of pollutants it is difficult for epidemiological studies to define causal agents in the mix. Asthma has been linked to a number of pollutants.

8. The most commonly studied are the criteria pollutants which are regulated in the United States by the Clean Air Act. The criteria pollutants are carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), particulate matter (PM10 and PM2.5) and lead (Pb). Of these, lead is not considered relevant to the development or exacerbation of asthma.

9. Laboratory studies suggest that pollutants can attach themselves to allergens such as pollen and increase their allergenic potential. Pollutants can induce airway inflammation and they can also facilitate the access of inhaled allergens to the cells of the immune system.