A study published in the May, 2014, edition of Environmental Research, “investigated associations of short-term changes in ambient ozone (O3), fine particulate matter (PM2.5) and nitrogen dioxide (NO2) concentrations and the timing of new-onset asthma, using a large, high-risk population in an area with historically high ozone levels. The study population included 18,289 incident asthma cases identified among Medicaid-enrolled children in Harris County Texas between 2005-2007, using Medicaid Analytic Extract enrollment and claims files. [Researchers] used a time-stratified case-crossover design and conditional logistic regression to assess the effect of increased short-term pollutant concentrations on the timing of asthma onset. Each 10ppb increase in ozone was significantly associated with new-onset asthma during the warm season (May-October), with the strongest association seen when a 6-day cumulative average period was used as the exposure metric….Similar results were seen for NO2 and PM2.5….[The] results indicate that among children in this low-income urban population who developed asthma, their initial date of diagnosis was more likely to occur following periods of higher short-term ambient pollutant levels.”

Click here to read the abstract.