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Asthma and Respiratory Related Emergency Room Visits Associated with a Wildfire in Eastern North Carolina in the Summer of 2008
Citation:
RAPPOLD, A. G., R. B. DEVLIN, M. S. CARRAWAY, J. V. KILARU, S. STONE, W. CASCIO, AND J. Szykman. Asthma and Respiratory Related Emergency Room Visits Associated with a Wildfire in Eastern North Carolina in the Summer of 2008. Presented at American Thoracic Annual Meeting, New Orleans, LA, May 14 - 19, 2010.
Impact/Purpose:
Preliminary findings indicate that exposure to smoke from the wildfire resulted in a statistically significant increase of relative risk for asthma related emergency room visits.
Description:
Rationale: Epidemiological studies have shown associations between the incidence of increased emergency room admissions, hospital and outpatient clinic visits for respiratory causes with the exposures to wood stove, wildfires, and other forms of organic mass burning. In June 2008 a lighting strike initiated a wildfire on North Carolina's Pocosin Lakes National Wildlife Park burning through peat moss and producing massive quantities of smoke. In order to investigate the association of adverse health effects and exposure to Pocosin wildfires, we evaluated the rates of asthma and other respiratory related emergency room visits on high and low exposure days of the counties affected by the wildfire. Methods: Eastern North Carolina is a region of homogeneous background with low population density and limited monitoring of air pollutants. High and low exposure gradients were identified through aerosol optical density (AOD) measurements from a GOES satellite. Individual level emergency room data included the date of visit, list of chief complaints, up to eleven discharge ICD9 codes, gender, and age. Locations of the emergency rooms were specified at the county level only. County level exposures were, therefore, obtained by areal integration of statistically interpolated daily AOD surfaces. A log-linear Poisson regression model was used to estimate the expected daily number of ER visits as a function of the dichotomous exposure predictor, adjusted for weekend and county level disease rates. Results: Preliminary findings indicate that exposure to smoke from the wildfire resulted in a statistically significant increase of relative risk for asthma related emergency room visits. A 12.4% (0-26.4%) association with smoke exposure was found with a day 0 lag and a 9.6% (0-22%) association with a day lag 1 . The small size (median 0.1um in diameter) and large concentration of carbon particles in the smoke permitted GOES AOD to trace the plume well. However, due to the small number FRM monitors in eastern NC, a direct relationship between AOD and measured pollutant levels could not be established at this time. Conclusions: These findings show that short-term exposure to smoke produced by the Pocosin Wildfires resulted in increased rates of emergency room visits due to asthma related respiratory complications. We are currently assessing the contribution of organic carbon, fine and ultrafine PM to the increased emergency room visits. This is an abstract ora proposedpresentation and does not necessarily reflect EPA policy.