On October 2, 2025 at 4 AM PT, air quality in Ulaanbaatar, Mongolia, is poor with an AQI of 145, classified as "unhealthy for sensitive groups".
The city continues to record some of the highest pollution levels in the world, driven by its reliance on coal for heating and industrial activities.
Residents face prolonged exposure to fine particulate matter (PM2.5), which significantly exceeds international health guidelines. Vulnerable groups such as children and the elderly are particularly at risk, with rising reports of respiratory illnesses (3).
Air quality is dynamic and, like the weather, can change frequently. Ulaanbaatar is ranked 2nd most polluted major city in the world on Thursday morning.
While the air quality conditions today are poor, it is important to keep in mind that the average PM2.5 concentration in 2024 for Ulaanbaatar was 25.7 µg/m³. This corresponds to an AQI of 79, which falls into the “moderate” category and was 5.1 times the WHO annual guideline of 5 µg/m³.

Published Date:2025-10-03