Health effects study of ambient formaldehyde exposure based on satellite remote sensing

Formaldehyde (HCHO) is a toxic and hazardous air pollutant that widely exists in atmosphere. Insufficient spatial and temporal coverage of surface HCHO measurements is limiting studies on surface HCHO-related air quality management and health risk assessment. The study derived global ground-level HCHO concentrations from satellite-based tropospheric HCHO columns. We conducted a two-stage time series analysis to investigate associations between ambient HCHO and daily nonaccidental, circulatory, and respiratory mortality in 275 Chinese counties. The results show that mortality risks in nonaccidental, circulatory, and respiratory diseases increased significantly and indicated a possible threshold concentration at approximately 5 ppb for significant impact on nonaccidental and circulatory diseases. Besides, global cancer burden caused by long-term outdoor HCHO exposure was estimated and we found up to 418188 more people worldwide will develop this cancer during the human life cycle. The global cancer burden is mainly from the South-East Asia region (33.11 %) and the Western Pacific region (22.95 %). This cancer occurrence in India and China is ranked 1st and 2nd in the world due to the large population size and serious HCHO pollution. Our results provide new insight into timely HCHO pollution regulation and health protection.