Combined Impacts of Urban Pollution and Wildland Fire Emissions on Human Health

Whereas, it is established that particulate pollution associated with smoke from wildland fires causes exacerbation of respiratory diseases, there are additional complexities associated with urban settings. In an urban setting, smoke pollution could co-occur with ozone pollution, exacerbating the effect of smoke. Further, depending upon the nature of the wildland fire, smoke plumes could interact with ozone chemistry, enhancing the production of ozone and leading to both particulate and ozone exceedances. Houston, TX, is an urban center where such concerns are relevant, as there is frequent intrusion of smoke from wildland fires within the United States and also from Mexico and Central America.

In this context, the differences in hospital admissions in Houston, TX during wildland fire events are examined. The Healthcare Cost and Utilization Project (H*CUP) Nationwide Inpatient Sample (NIS) database is being utilized for this purpose. Occurrence of smoke in the study region is determined through the use of National Oceanic and Atmospheric Administration (NOAA) Hazard Mapping System (HMS). Inpatient admission statistics from H*CUP are categorized based on the International Classification of Diseases-9th Revision (ICD-9) for asthma, chronic obstructive pulmonary disease (COPD), bronchitis, and other respiratory diseases such as pneumonia that are present as a primary or secondary diagnosis. The following analysis based on this dataset will be presented. Based on the diagnoses categorization, counts of inpatient admissions for similar diagnoses are compared for a two-week period before and after the time of the wildland fire event. Because weekday and weekend admission rates can differ, pre-fire weekday and weekend admissions are also be compared. Differences in lengths of stay for the disorders, including both pre- and post-fire periods, are also calculated.