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Abstract: On August 29, 2005, Hurricane Katrina made landfall near New Orleans, Louisiana, a major metroplex with petroleum industries. In response to the potential impact of the storm on air quality and to assess the exposures to toxic air pollutants of public health concern, the United States Environmental Protection Agency conducted passive monitoring of air toxics for three months, starting in late October 2005 through early February 2006, at up to 18 sites in the New Orleans area affected by Hurricane Katrina. The overall results of the passive ambient monitoring are summarized with the concentrations for the twenty-nine observed volatile organic chemicals, which include benzene, toluene, ethylbenzene, and xylenes, and the measured concentrations are compared with available health-based screening levels. The results of passive monitoring are also compared with those of the collocated canister sampling at one of the sites. The overall results showed that the outdoor levels of atmospheric volatile organic chemcals in the post-Katrina New Orleans area were very low and far below the available screening levels. The results also confirm the effectiveness of passive monitoring in a large geographical area where conventional methods are not feasible, electrical power is not available, and the need for sampling is urgent, as in the aftermath of natural disasters and other catastrophes. [Copyright &y& Elsevier]

Abstract: Objective: We 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. Methods: 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. We 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. Results: 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 (odds ratio [OR]=1.05, 95% confidence interval [CI], 1.02–1.08). Similar results were seen for NO2 and PM2.5 (OR=1.07, 95% CI, 1.03–1.11 and OR=1.12, 95% CI, 1.03–1.22, respectively), and PM2.5 also had significant effects in the cold season (November–April), 5-day cumulative lag (OR=1.11. 95% CI, 1.00–1.22). Significantly increased ORs for O3 and NO2 during the warm season persisted in co-pollutant models including PM2.5. Race and age at diagnosis modified associations between ozone and onset of asthma. Conclusion: Our 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. [Copyright &y& Elsevier]