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Acute effects of ambient ozone on asthmatic, wheezy, and healthy children
E L Avol1, W C Navidi, E B Rappaport
1University of Southern California, Division of Occupational and Environmental Medicine, School of Medicine, Los Angeles, USA.
Insights
Children with asthma and wheezing show varied responses to ambient ozone (O3), with inconsistent patterns in symptoms and activity levels. Further research is needed to clarify these effects on pediatric respiratory health.
Area of Science:
- Environmental Health
- Pediatric Respiratory Medicine
- Air Pollution Studies
Background:
- Ambient ozone (O3) is a significant air pollutant with known respiratory effects.
- Children, particularly those with pre-existing respiratory conditions like asthma, may be more vulnerable to air pollution impacts.
- Understanding the acute effects of O3 on children's respiratory health is crucial for public health interventions.
Purpose of the Study:
- To assess the acute respiratory effects of ambient ozone on children aged 10-12 in Southern California.
- To compare the responses of asthmatic, wheezy, and healthy children to varying ozone exposures.
- To investigate the relationship between personal ozone exposure, physical activity, and respiratory symptoms.
Main Methods:
- A two-season study involving 195 children (49 asthmatic, 53 wheezy, 93 healthy).
- Children completed a four-day protocol in spring and summer, using symptom diaries, heart rate monitors, personal O3 samplers, and spirometry.
- Ambient O3 concentrations were monitored using regional stations and personal samplers.
Main Results:
- Children spent more time outdoors and were more active in spring than summer; boys were more active than girls.
- Personal O3 samplers showed poor correlation with ambient monitors.
- Higher personal O3 exposure was linked to increased inhaler use, outdoor time, and physical activity.
- Asthmatic children exhibited more symptoms and inhaler use on high O3 days in spring but reduced activity in summer.
- Wheezy children reported more breathing difficulties on low O3 days in summer.
Conclusions:
- Asthmatic and wheezy children demonstrate altered behaviors in response to ambient ozone compared to healthy children.
- The observed relationships between ozone exposure and respiratory outcomes were inconsistent and difficult to interpret.
- The precise nature of ozone's acute respiratory effects on children remains ill-defined and warrants further investigation.
Abstract:
Southern California children (10 to 12 years old) participated in a two-season study to assess the potential acute respiratory effects of ambient ozone (O3). Asthmatic (n = 49), wheezy (n = 53), and healthy (n = 93) children completed a four-day (Friday through Monday) study protocol, once in spring and again in summer, that included the use of daily activity and symptom diaries, heart rate recording devices, personal O3 samplers, and maximal effort spirometry several times per day. Data from regional monitoring stations were used to establish ambient hourly O3 concentrations. Analyses revealed that the children spent more time outdoors and were more physically active in the spring. Girls spent less time outdoors and were less physically active than boys. Personal O3 samplers correlated poorly with, and generally gave lower readings than, outdoor ambient monitors. Higher personal O3 exposures were associated generally with increased inhaler use, more outdoor time, and more physical activity. Children with asthma spent more time outdoors and were more active in the spring on high-O3 days (measured by personal sampler), and had the most trouble breathing, the most wheezing, and the most inhaler use on these days. Activity pattern data suggested that children with asthma protected themselves by being less physically active outdoors during the summer on high-O3 days. Wheezy children had the most trouble breathing during the summer on low-O3 days (measured by personal sampler). Observed relationships between O3 and pulmonary function were erratic and difficult to reconcile with existing knowledge about the acute respiratory effects of air pollution. We conclude that although asthmatic and wheezy children behave differently from their healthy peers with regard to symptoms and patterns of activity when challenged by ambient ozone, the nature of these changes remains inconsistent and ill-defined.