Exposure to air pollution is associated with lung hyperinflation in healthy children and adolescents in Southwest Mexico City: A pilot study

Air pollution produces adverse health effects. The consequences of lifelong daily exposures to atmospheric pollutants upon the respiratory apparatus o f healthy children are of considerable clinical importance. We investigated the association between exposure to a highly polluted urban environment wi th a complex mixture of air pollutants-ozone and particulate matter the pre dominant ones-and chest x-ray abnormalities in 59 healthy Mexican children who are lifelong residents of Southwest Metropolitan Mexico City (SWMMC), w ith a negative history of tobacco exposure and respiratory illnesses. Their clinical results and x-ray findings were compared to those of 19 Mexican c ontrol children. residents of a low-pollution area, with a similar negative history of tobacco exposure and respiratory illnesses. Ozone concentration s in SWMMC exceeded the U.S. Environmental Protection Agency (U.S. EPA) Nat ional Ambient Air Quality Standard (NAAQS) for O-3: 0.08 ppm as 1-h maximal concentration, not to be Exceeded more than 4 times a year, on 71% of days in 1986 and 95% in 1997, with values as high as 0.48 ppm. Ozone maximal pe aks are usually recorded between 2 and 5 pm coinciding with children's outd oor physical activities. Children in the control group reported no upper or lower respiratory symptomatology. Every SWMMC child complained of upper an d/or lower respiratory symptoms, including epistaxis, nasal dryness and cru sting, cough, shortness of breath, and chest discomfort Children aged 7-13 yr had the most symptomatology, while 5- to 6-year olds and adolescents wit h the lowest number of statistically significant outdoor exposure hours had less respiratory symptoms. Bilateral symmetric mild lung hyperinflation wa s significantly associated with exposure to the SWMMC atmosphere (p = .0004 ). Chronic and sustained inhalation of a complex mixture of air pollutants, including ozone and particulate matter (PM), is associated with lung hyper inflation, suggestive of small airway disease, in a population of clinicall y healthy children and adolescents. Small airways are a target of air pollu tants in SWMMC children, with ozone and PM being most likely responsible, b ased on experimental animal, controlled-chamber, and epidemiological data a vailable. Our main concern is the potential likelihood for the development of chronic lung disease in this highly exposed population.