Ulaanbaatar's Raw-Coal Ban & Ger-District Heating Transition

Ulaanbaatar's ger districts house roughly half the capital's population in unplanned, non-networked housing reliant on individual coal stoves, and winter PM2.5 levels there have ranked among the world's highest, disproportionately affecting pregnant women and young children.

With a policy-based loan from the Asian Development Bank, the government sought to cut particulate pollution by banning raw, unprocessed coal for household heating and cooking citywide from 15 May 2019, replacing it with subsidised semi-processed coal briquettes intended to burn more cleanly.

A peer-reviewed interrupted time-series study covering May 2016–December 2021 assessed ambient air-quality and child-health data before and after the ban, while the Asian Development Bank separately tracked its own results reporting against the government's air-quality target.

The study found an immediate drop in ambient PM2.5 of 17.1 µg/m³, rising to 45.3 µg/m³ in peak winter months, with pre-ban median PM2.5 of 45.9 µg/m³ falling to 27.1 µg/m³ after the ban; the ADB separately reported a 51% fall in average winter ambient PM2.5 between 2016-17 and 2019-20, exceeding the government's 30% reduction target. However, once the study adjusted for the confounding effect of COVID-19 social-distancing restrictions, the earlier apparent improvement in severe child respiratory hospital visits was not statistically significant, and the switch to briquettes caused statistically significant increases in SO2 (+81.6 µg/m³ in peak winter months) and CO (+56.1 µg/m³ monthly in winter).

The case shows a real, well-evidenced particulate-matter improvement alongside a genuinely mixed public-health and pollutant-trade-off record once the data was analysed rigorously and confounders were properly accounted for.