The Effect of Tree Cover and Vegetation on Incidence of Childhood Asthma in Metropolitan Statistical Areas of Texas

Abstract

The number of asthma cases in children has increased significantly in the last couple of decades. Studies on links between outdoor air pollutants and asthma have had mixed results, suggesting the need for more focused studies. An increase in tree plantings for urban areas is now being called upon as a solution to the higher heat indexes and pollution rates for more densely populated areas. Green spaces and trees could further benefit some urban areas by providing an effective means to improve air conditions. The purpose of this study was to assess whether there is a relationship between levels of vegetation and reported rates of childhood asthma in Texas. Childhood asthma data were collected from the Center for Health Statistics and the Texas Department of State Health Services for the years 2005 and 2006. The asthma rates for each metropolitan statistical area (MSA) were mapped and inserted into a corresponding vegetation map using geographical mapping software. A comparison of vegetation rates and asthma rates in metropolitan areas was used to investigate whether vegetation and tree cover led to higher or lower incidences of childhood asthma rates. Asthma data, normalized difference vegetation index (NDVI), and canopy cover data were analyzed using statistical software. Regression analysis and correlations were calculated to analyze the data for the tree coverage/vegetation rates and asthma rates variable. No statistically significant relationships between NDVI, canopy cover, and asthma were found in this study.