SmogRank / World / North America / Mexico / Coahuila
Most polluted cities in Coahuila, Mexico
1 measured city, last 30 days; 1 above the WHO 24-hour guideline. The only one: Saltillo at 18.2 µg/m³, #276 in the world.
Ranked by unhealthy days: the share of each city's measured days with a daily mean over 35.4 µg/m³ (US AQI 101+), Unhealthy for Sensitive Groups or worse on the US EPA's scale. Ties go to the higher average.
Cities coloured by their PM2.5 over the last 24 hours. Fires, smoke and ash: Oct 5, the newest UTC day mapped.
- 1Saltillo 13%
The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales
Estimated: cities without a monitor
Coahuila cities we can't measure, with model estimates for the last 7 days. Listed by population, not ranked: estimates aren't precise enough to rank. Model estimates from the Copernicus Atmosphere Monitoring Service (CAMS), adjusted to measured cities nearby where there are any. Adjusted, a single day lands within ×1.5 of what a monitor would read about two times in three; unadjusted, it can be off by half or double. Treat them as a guide, not a measurement.
| City | 7-day estimate |
|---|---|
| Torreón | ≈ 14 µg/m³ |
| Ciudad Acuña | ≈ 5 µg/m³ |
| Monclova | ≈ 11 µg/m³ |
| Frontera | ≈ 11 µg/m³ |
| Ramos Arizpe | ≈ 9 µg/m³ |
| Sabinas | ≈ 8 µg/m³ |
| Matamoros | ≈ 12 µg/m³ |
| San Pedro | ≈ 10 µg/m³ |
| San Pedro | ≈ 12 µg/m³ |
| Nueva Rosita | ≈ 8 µg/m³ |
| Ciudad Melchor Múzquiz | ≈ 8 µg/m³ |
| Parras de la Fuente | ≈ 8 µg/m³ |
| Francisco I. Madero | ≈ 12 µg/m³ |
| Castaños | ≈ 11 µg/m³ |
| Nava | ≈ 8 µg/m³ |
| Allende | ≈ 8 µg/m³ |
| San Buenaventura | ≈ 10 µg/m³ |
| Palaú | ≈ 8 µg/m³ |
Bad-air episodes in Coahuila
- Southern United States and Mexico, March and April 202530 March to 1 April 2025, 3 days9 cities111 µg/m³peak, Saltillo
- Southern United States and Mexico, June 20242 to 6 June 2024, 5 days22 cities86 µg/m³peak, Saltillo
- Southern United States and Mexico, 19 to 28 May 202410 days44 cities75 µg/m³peak, Port Isabel
Times when many cities around here had PM2.5 at twice their usual or more on the same days.
Use this board
SmogRank, most polluted cities in Coahuila, Mexico, PM2.5, last 30 days to 7 Oct 2026, 01:00 UTC, smogrank.com/mx/region/coahuila?w=30d.
You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.
Updated 2026-10-07 01:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index.