EXPOSURE TO AIR POLLUTION IS ASSOCIATED WITH LUNG HYPERINFLATION IN HEALTHY CHILDREN AND ADOLESCENTS IN SOUTHWEST MEXICO CITY: A Pilot Study

Abstract

Air pollution produces adverse health effects. The consequences of lifelong daily exposures to atmospheric pollutants upon the respiratory apparatus of healthy children are of considerable clinical importance. We investigated the association between exposure to a highly polluted urban environment with a complex mixture of air pollutants-ozone and particulate matter the predominant ones-and chest x-ray abnormalities in 59 healthy Mexican children who are lifelong residents of Southwest Metropolitan Mexico City (SWMMC), with a negative history of tobacco exposure and respiratory illnesses. Their clinical results and x-ray findings were compared to those of 19 Mexican control children, residents of a low-pollution area, with a similar negative history of tobacco exposure and respiratory illnesses. Ozone concentrations in SWMMC exceeded the U.S. Environmental Protection Agency (U.S. EPA) National 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 peaks are usually recorded between 2 and 5 pm coinciding with children's outdoor physical activities. Children in the control group reported no upper or lower respiratory symptomatology. Every SWMMC child complained of upper and/or lower respiratory symptoms, including epistaxis, nasal dryness and crusting, cough, shortness of breath, and chest discomfort. Children aged 7-13 yr had the most symptomatology, while 5- to 6-year olds and adolescents with the lowest number of statistically significant outdoor exposure hours had less respiratory symptoms. Bilateral symmetric mild lung hyperinflation was 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 hyperinflation, suggestive of small airway disease, in a population of clinically healthy children and adolescents. Small airways are a target of air pollutants in SWMMC children, with ozone and PM being most likely responsible, based on experimental animal, controlled-chamber, and epidemiological data available. Our main concern is the potential likelihood for the development of chronic lung disease in this highly exposed population.

Risk assessment of PM2.5 to child residents in Brazilian Amazon region with biofuel production

“…The children under the age of 8 showed toxicological PM 2.5 risk 12% higher than the risk for adolescents (12–14 years). Our results corroborate other studies such as Calderon-Garciduanas et al (2000) [43] which found that the long term inhalation of air pollutants such as PM was associated with lung hyperinflation indicative of small airway disease and that children between the ages of 7–13 had more symptoms when compared to 5–6 year olds and adolescents. Another study conducted in the metropolitan zone of Mexico city [44] utilized the same methodology of evaluating the health risk of PM 2.5 inhalation, however, differentiated into three different age groups: children 2–6 years of age, children 6–12 years old and adults.…”

Acute Ozone-Induced Transcriptional Changes in Markers of Oxidative Stress and Glucocorticoid Signaling in the Rat Hippocampus and Hypothalamus Are Sex-Specific

“…This observational study comparing sex differences in O 3 -induced OS and glucocorticoid-mediated transcriptional changes neither assessed potential protein levels of markers or functional effects, and rather associated changes to our prior publications related to neural and glucocorticoid changes. The O 3 concentrations used are several folds higher than what is encountered environmentally in tropical atmospheres, however, they are comparable to human clinical studies performed during intermittent exercise with O 3 concentrations ranging from 0.2 to 0.4 ppm [ 77 , 78 , 79 , 80 ]. Humans exposed during intermittent exercise retain 4–5 times the inhaled dose of O 3 compared to rodents exposed during rest [ 81 ].…”

Controlled Exposure of Healthy Young Volunteers to Ozone Causes Cardiovascular Effects

“…Although higher than the Environmental Protection Agency National Ambient Air Quality Standards standard of 0.076 ppm and not seen in American cities, it is only slightly higher than peak hourly concentrations observed in heavily polluted cities such as Beijing and Mexico City. 16,17 In addition, the subjects in this study were exposed to elevated levels of ozone for only 2 hours, in contrast to "real-life" situations that would involve much lengthier ozone exposures. Each exposure was separated by at least 2 weeks.…”