Restrictions on indoor and outdoor NO₂ emissions to reduce disease burden for pediatric asthma in China: A modeling study.

Abstract

Epidemiological studies have reported the associations between nitrogen dioxide (NO₂) and pediatric asthma incidence, but unable to ascertain indoor NO₂ sources. We estimated the pediatric asthma incidence and corresponding economic losses attributable to NO₂ from indoor and outdoor sources in urban areas in China. Exposure to NO₂ from indoor and outdoor sources in 2019 were estimated separately with a source-specific model validated by measurements from different studies, and NO₂ exposure after restricting emissions indoor (from cooking or second-hand smoking) and outdoor (to meet WHO interim targets and air quality guideline) were projected. Disease burden of NO₂-attributable new-onset pediatric asthma were estimated based on NO₂ exposure, concentration-response function from a meta-analysis, and number of pediatric asthma populations. Economic impacts were estimated based on the costs of pediatric asthma in China. In China, NO₂ is associated with an estimated 637,000 (95% uncertainty interval 358,000-851,000) new pediatric asthma cases and 1,358 million (674-2145) RMB economic losses in urban areas in 2019. 296,000 (222,000-523,000) new pediatric asthma cases would be prevented each year by restricting NO₂ emissions indoor, i.e., switching from using gas stoves to electic stoves for cooking. 393,000 (119,000-463,000) new pediatric asthma cases would be prevented each year when outdoor air meets the air quality guideline for NO₂ (< 10 µg/m³). Restricting both indoor and outdoor NO₂ emissions are necessary to reduce pediatric asthma incidence in urban areas. NO₂ restrictions may be achieved through clean energy transition and adoption of climate change mitigation activities. Vanke School of Public Health, Tsinghua University (2021JC005).