 In a longitudinal, prospective study, men who were exposed to a 27 parts per billion increase were found to have a 2-fold increase in asthma diagnosis.Although this trend was not found for women, the size of this ozone effect was not diminished when the researchers considered other air pollutants such as (PM10, SO4, NO2, and SO2).Additionally, it was found that after ozone levels equaled or exceeded 0.11 ppm, there was a 37% increase in hospital visits for asthma for African American families in low income areas.