Office of Border Health

Assessment of Children's Respiratory Symptoms and Air Quality in Ambos Nogales (Arizona and Sonora)

Executive Summary:

Residents of Nogales, Arizona have raised concerns about the quality of air and its possible relationship to respiratory symptoms. In response, multiple agencies collaborated in a study during the autumn of 1996 to determine the prevalence of respiratory symptoms among the 5th grade students in the border towns of Ambos Nogales (Arizona and Sonora). Parents and students completed baseline questionnaires. During the 11 weeks of the study, 631 students recorded their daily respiratory symptoms daily and measured their peak expiratory flow rates twice per school day. The agencies collected air quality data during the study period.

Air quality measurements revealed considerable day-to-day variation in the level of particulate matter (PM). PM levels tended to be greater on the Sonora side of the border. Measurements of PM, carbon monoxide and ozone levels on the Arizona side were consistently below the maximum US air quality standards. Respiratory symptoms and peak flow measurements were linked to PM levels. Respiratory symptoms noted by the children on both sides of the border increased with PM increase. Also, there was an inverse correlation between PM level and peak expiratory flow rate

The study found that the prevalence of self-reported asthma among 5th grade students was 7.6% on the Arizona side and 6.9% on the Sonora side. The prevalence of respiratory symptoms such as wheezing and frequent cough, as well as the limitations inherent in self-reporting, suggests in the prevalence of asthma-like respiratory diseases may actually be higher. Smoking in the home was common on both sides of the border and was associated with a greater risk of self-reported asthma and respiratory complaints.

Further efforts are needed to control the level of PM in Ambos Nogales. Reduction in PM on both sides of the border could result in modest reductions of respiratory symptoms and improved respiratory health among children. Anti-smoking efforts aimed at parents could reduce children's exposure to second hand smoke and remove a known trigger of asthma. Children with persistent, undiagnosed, respiratory symptoms are encouraged to consult with their physicians.