Improving Air Quality and Childhood Respiratory Health in Mongolia: The Impact of the Raw Coal Ban and COVID-19 Restrictions—An Interrupted Time-Series Analysis

Background: In May 2019, Ulaanbaatar, Mongolia introduced a city-wide raw coal ban (RCB) to improve ambient air quality. Air pollution exposure particularly affects child health and is associated with acute respiratory disease. We assessed the effects of the RCB on air quality and child respiratory health. Methods: An interrupted time-series analysis was conducted on air quality (PM2.5, PM10, SO2, CO) and child (10 significantly decreased by −34.3 µg/m3 (95% CI −62.9, −5.8, p = 0.02) and PM2.5 by −17.1 µg/m3 (95% CI −26.3, −7.9, p < 0.01), immediately post-intervention. The subgroup analysis showed SO2 increased by 81.6 µg/m3 (95% CI 45.2, 117.9, p < 0.01) in the first month and by 4.9 µg/m3 (95% CI 2.6, 7.3, p < 0.01) monthly afterwards. CO increased by 56.1 µg/m3 (95% CI 13.5, 98.7, p = 0.01). Child respiratory health showed no significant change after adjusting for the COVID-19 effect. Discussion: The RCB successfully reduced key pollutants (PM), almost instantly. Long-term increases in SO2 and CO and limited health effects highlight the need for further air quality improvements. Outputs from Mongolia’s continuous air quality mitigation efforts provide useful insights for countries facing similar challenges.