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

Objective : The main sources of nitrogen dioxide (NO 2 ), 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 NO 2 by 25% from current levels. Methods : 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, NO 2 exposure from a land‐use regression model using satellite data, and risk estimates derived from two meta‐analyses and one Australian study. Results : A 25% reduction in NO 2 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. Conclusions : Even the lowest of these estimates would be a worthwhile reduction in this common childhood illness. Implications for public health : A 25% reduction in NO 2 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 NO 2 should be revised downwards.