CONTEXT: Exposure to ozone and particulate matter of 2.5 microm or less (PM2.5) in air at levels above current US Environmental Protection Agency (EPA) standards is a risk factor for respiratory symptoms in children with asthma. OBJECTIVE: To examine simultaneous effects of ozone and PM2.5 at levels below EPA standards on daily respiratory symptoms and rescue medication use among children with asthma. DESIGN, SETTING, AND PARTICIPANTS: Daily respiratory symptoms and medication use were examined prospectively for 271 children younger than 12 years with physician-diagnosed, active asthma residing in southern New England. Exposure to ambient concentrations of ozone and PM2.5 from April 1 through September 30, 2001, was assessed using ozone (peak 1-hour and 8-hour) and 24-hour PM2.5. Logistic regression analyses using generalized estimating equations were performed separately for maintenance medication users (n = 130) and nonusers (n = 141). Associations between pollutants (adjusted for temperature, controlling for same- and previous-day levels) and respiratory symptoms and use of rescue medication were evaluated. MAIN OUTCOME MEASURES: Respiratory symptoms and rescue medication use recorded on calendars by subjects' mothers. RESULTS: Mean (SD) levels were 59 (19) ppb (1-hour average) and 51 (16) ppb (8-hour average) for ozone and 13 (8) microg/m3 for PM2.5. In copollutant models, ozone level but not PM2.5 was significantly associated with respiratory symptoms and rescue medication use among children using maintenance medication; a 50-ppb increase in 1-hour ozone was associated with increased likelihood of wheeze (by 35%) and chest tightness (by 47%). The highest levels of ozone (1-hour or 8-hour averages) were associated with increased shortness of breath and rescue medication use. No significant, exposure-dependent associations were observed for any outcome by any pollutant among children who did not use maintenance medication. CONCLUSION: Asthmatic children using maintenance medication are particularly vulnerable to ozone, controlling for exposure to fine particles, at levels below EPA standards.
CONTEXT: Exposure to ozone and particulate matter of 2.5 microm or less (PM2.5) in air at levels above current US Environmental Protection Agency (EPA) standards is a risk factor for respiratory symptoms in children with asthma. OBJECTIVE: To examine simultaneous effects of ozone and PM2.5 at levels below EPA standards on daily respiratory symptoms and rescue medication use among children with asthma. DESIGN, SETTING, AND PARTICIPANTS: Daily respiratory symptoms and medication use were examined prospectively for 271 children younger than 12 years with physician-diagnosed, active asthma residing in southern New England. Exposure to ambient concentrations of ozone and PM2.5 from April 1 through September 30, 2001, was assessed using ozone (peak 1-hour and 8-hour) and 24-hour PM2.5. Logistic regression analyses using generalized estimating equations were performed separately for maintenance medication users (n = 130) and nonusers (n = 141). Associations between pollutants (adjusted for temperature, controlling for same- and previous-day levels) and respiratory symptoms and use of rescue medication were evaluated. MAIN OUTCOME MEASURES: Respiratory symptoms and rescue medication use recorded on calendars by subjects' mothers. RESULTS: Mean (SD) levels were 59 (19) ppb (1-hour average) and 51 (16) ppb (8-hour average) for ozone and 13 (8) microg/m3 for PM2.5. In copollutant models, ozone level but not PM2.5 was significantly associated with respiratory symptoms and rescue medication use among children using maintenance medication; a 50-ppb increase in 1-hour ozone was associated with increased likelihood of wheeze (by 35%) and chest tightness (by 47%). The highest levels of ozone (1-hour or 8-hour averages) were associated with increased shortness of breath and rescue medication use. No significant, exposure-dependent associations were observed for any outcome by any pollutant among children who did not use maintenance medication. CONCLUSION: Asthmatic children using maintenance medication are particularly vulnerable to ozone, controlling for exposure to fine particles, at levels below EPA standards.
Authors: David M Hondula; Robert E Davis; David B Knight; Luke J Sitka; Kyle Enfield; Stephen B Gawtry; Phillip J Stenger; Michael L Deaton; Caroline P Normile; Temple R Lee Journal: Int J Biometeorol Date: 2012-03-22 Impact factor: 3.787
Authors: Matthew J Strickland; Lyndsey A Darrow; Mitchel Klein; W Dana Flanders; Jeremy A Sarnat; Lance A Waller; Stefanie E Sarnat; James A Mulholland; Paige E Tolbert Journal: Am J Respir Crit Care Med Date: 2010-04-08 Impact factor: 21.405
Authors: Stephanie A Shore; Erin S Williams; Lucas Chen; Leandro A P Benedito; David I Kasahara; Ming Zhu Journal: Inhal Toxicol Date: 2011-11-08 Impact factor: 2.724
Authors: Chris C Lim; Richard B Hayes; Jiyoung Ahn; Yongzhao Shao; Debra T Silverman; Rena R Jones; Cynthia Garcia; Michelle L Bell; George D Thurston Journal: Am J Respir Crit Care Med Date: 2019-10-15 Impact factor: 21.405