Air pollution morbidity along the U.S.-Mexico border.
The rapid increase in population near highways and roads along the
United States-Mexico border has raised concerns about the health impact
or urban air pollution on children with asthma. Sarnat et al. (p. 437)
studied 58 asthmatic children from two schools in Ciudad Juarez, Mexico,
and two schools in El Paso, Texas. Health outcomes (exhaled nitric oxide (eNO), a marker of airway inflammation, and respiratory symptom surveys]
and pollutant measurements (indoor and outdoor 48-hr size-fractionated
particulate matter, 48-hr black carbon, and 96-hr nitrogen dioxide) were
collected at each school for 16 weeks. Small associations were observed
between eNO and pollutants, with estimated increases in eNO of 1--3% per
interquartile range increase in pollutant concentrations. Effect
estimates from models using school-based concentrations were generally
stronger than were corresponding estimates based on concentrations from
ambient air monitors. Traffic-related and non--traffic-related particles
were typically more robust predictors of eNO than was nitrogen dioxide.
Associations differed significantly across the four school-based
cohorts, consistent with heterogeneity in pollutant concentrations and
cohort characteristics. The authors conclude that air pollution exposure
has adverse effects on the subclinical respiratory health of children
with asthma and suggest that using air pollution monitors near schools
might be beneficial in tracking exposure and potential health risks in
this susceptible population.