Childhood Asthma in the U.S.-Mexico Border Region: Trends in Hospitalizations and Air Quality
EHIB examined air quality data from 1983 to 1994 in two counties on the US-Mexico border to investigate trends in childhood asthma hospitalizations. The study period marked growing industrialization and rapid increases in population in San Diego and Imperial Counties, which are both located on the California-Mexico border.
Air quality findings reported that that both counties failed to meet state standards for ozone and particulate matter, pollutants known to aggravate asthma. Imperial County reported the highest rates of childhood asthma in California for non-Hispanic whites and African-Americans, and the second highest for Hispanics. San Diego County reported rates below the state average.
Reasons for this disparity are discussed in the scientific journal article published in 1998. Further research on the relationship between air pollutants and asthma prevalence in the border region was recommended.
Abstract of the scientific journal article:
Since the passage of the North American Free Trade Agreement in 1993, there has been an increasing need to monitor environmental health trends that may be related to the rapid industrialization of the United States/Mexico border. We studied two counties on the California/Baja California border to obtain baseline data on trends in childhood asthma hospitalizations and two pollutants that aggravate asthma, ozone and particulate matter (less than 10 microns in diameter), from 1983 to 1994. Hospital discharge records of children 14 years and younger were analyzed, and rates by county, race, and sex were age-adjusted to the 1990 California population. Data on five ozone and particulate matter indices obtained from the California Environmental Protection Agency were used. Imperial County had the highest childhood asthma hospitalization rates in California for non-Hispanic whites and African-Americans, and the second highest for Hispanics. San Diego County had rates below the state average. Over the time period examined, rates in Imperial County increased 59%, while those in San Diego County decreased 9%. Maximum ozone levels increased 64% in Imperial County but decreased 46% in San Diego County. Particulate matter levels were four times higher in Imperial than in San Diego County. High rates of childhood asthma hospitalizations in Imperial County may be partially related to high levels of poverty and worsening air quality conditions produced by increased burdens on the local airshed. Asthma prevalence surveys and binational time-series analyses examining asthma-pollutant relationships are needed.