Is neighborhood green space protective against associations between child asthma, neighborhood traffic volume and perceived lack of area safety? Multilevel analysis of 4447 Australian children
Protecting child respiratory health may be more effective if focused on expanding green space to buffer air pollution rather than trying to improve perceived safety
Heavy traffic volume is associated with a type of air pollution referred to as “particulate matter” which is dangerous for a range of health outcomes, including child asthma. Heavy traffic is also a safety concern of parents in many urban neighborhoods. This study considers whether parent perceptions of heavy traffic might influence their children’s asthma risk — not necessarily or exclusively because of air pollution — but over general safety concerns as stress, resulting from threats to safety, could contribute to asthma symptoms. The primary purpose of the study was to investigate the potential of green space as a modifier of environmental factors associated with asthma risk and to determine to what extent traffic volume may be a proxy for neighborhood safety rather than air pollution.
Researchers analyzed data from a nationally representative sample of 4447 Australian children, aged 6-7 years old. Case finding of children with affirmative asthma within this sample was based on parent report of all three of the following conditions: doctor diagnosis of childhood asthma, medication for asthma taken in the last 12 months, and an illness with wheezing in the chest lasting for a week or more. Parent report also provided data on perceptions of traffic volume near the household and perceived neighborhood safety. Additional data included objective measures of neighborhood green space (based on a percentage of land-use within a designated area of a local community).
Affirmative asthma was reported for 8.7% of all the participants. For children living in high traffic areas, the prevalence of affirmative asthma was 11.7%; for children living in low traffic areas, 7.5%. In neighborhoods with little green space coverage (20% or less), the prevalence of affirmative asthma was 9.2%. In neighborhoods with 20 – 40% of green space, the prevalence of affirmative asthma was 8.1%; and in neighborhoods with more than 40% green space, the prevalence was 7.5%. There was an association between traffic and asthma for children living in neighborhoods with lower levels of greenspace. However, this association was significantly lower for children living in areas with over 40% greenspace, suggesting green space can serve as a buffer against traffic-induced asthma. Results showed no association between affirmative asthma and green space coverage for children not exposed to heavy traffic. There was also no association between perceived neighborhood safety and asthma risk.
These findings indicate that efforts to protect child respiratory health may be more effective if focused on enhancing local air quality rather than improving perceived levels of neighborhood safety. One way to buffer traffic-related air pollution is to increase the quantities of nearby green space. This study suggests that while smaller amounts of neighborhood green space may have some health-related benefits, larger quantities may be necessary to protect children’s respiratory health. These findings support the protection of existing green spaces and investments in new urban greening to partially offset the harmful effects of air pollution on child respiratory health.
Citation
Feng, X., Astell-Burt, T., (2017). Is neighborhood green space protective against associations between child asthma, neighborhood traffic volume and perceived lack of area safety? Multilevel analysis of 4447 Australian children. International Journal of Environmental Research and Public Health, 14(5)
