Opportunity to reduce paediatric asthma in New South Wales through nitrogen dioxide control

The main sources of nitrogen dioxide (NO₂ ), road vehicles and electricity generation, are currently in a period of technological change. We assessed the number of cases of childhood asthma in New South Wales that could be avoided by lowering exposure to NO₂ by 25% from current levels.

Health impact assessment calculations for each of the 128 local government areas were based on the population of children aged 2 to 14, the prevalence of asthma derived from the 2017 NSW health survey, NO₂ exposure from a land-use regression model using satellite data, and risk estimates derived from two meta-analyses and one Australian study.

A 25% reduction in NO₂ below current exposure would lead to between 2,597 and 12,286 fewer children with asthma in NSW. The wide range in these estimates reflects the variation in concentration-response functions used.

Even the lowest of these estimates would be a worthwhile reduction in this common childhood illness. Implications for public health: A 25% reduction in NO₂ is ambitious, but it is achievable through improved vehicle exhaust standards, increasing electric vehicle numbers, and reform of the electricity sector. Current Australian ambient air quality standards for annual NO₂ should be revised downwards.