Correlation Study of the Association of PM10 with the Main Respiratory Diseases in the Populations of Mexicali, Baja California and Imperial County, California

Resumen

Mexicali is the third most contaminated city in Mexico and the second city in the country with the highest level of particles smaller than 10 micrometers in diameter (PM10). It continuously fails to meet annual air quality standards (50 µg/m3). Mexicali’s U.S. neighbor, the Imperial County, has the same geographical characteristics and is in non-attainment for PM10, ozone, and carbon monoxide. One health condition associated with high PM10 levels is asthma and both Imperial Valley and Mexicali have the highest child asthma indices for their respective states of California and Baja California. PM10 is primarily formed naturally, from dust and pollen, but anthropogenic sources are gaining importance due to an accelerated growth in this bi-national basin. Thermoelectric plants recently constructed are an example of this accelerated growth and their construction prompts bi-national concern in a basin with an already deteriorated air quality. There are a limited number of published documents focusing on Mexicali’s and Imperial County’s health or environment. Only a few articles contain data on PM10 levels or respiratory illnesses (including asthma), and even less jointly report on health conditions and the environment. This lack of information has produced flawed and unproductive environmental policy in the U.S.-Mexican border region. A model based on the Poisson regression was used to study the impact PM10 may have had on primary respiratory diseases given the temperature and relative humidity in the Imperial Valley-Mexicali basin. The years 1997 to 2000 were measured in series by seasons. Air quality data, specifically PM10 data, were supplied by a regional network of air monitoring stations in the Imperial Valley and Mexicali. Health data, including asthma, acute respiratory infections, bronchitis, and pneumonia were obtained from Baja California public health centers and the California Office of Statewide Health Planning and Development, Healthcare Quality and Analysis Division.