SmogRank / World / North America / Mexico / Baja California
Most polluted cities in Baja California, Mexico
2 measured cities, this year; 2 above the WHO annual guideline. Worst: Mexicali at 22.4 µg/m³, #313 in the world.
About 63.8K people in this city breathed unhealthy air on an average day so far this year.
Ranked by people: each city's population times its share of unhealthy days, those with a daily mean over 35.4 µg/m³ (US AQI 101+). That is how many people living there breathed unhealthy air on an average day. Only cities measured at 2 or more places at least 3 km apart are ranked: one monitor shouldn't speak for a whole city. Population is the city itself, not its wider metro area.
Cities coloured by their PM2.5 over the last 24 hours. Fires, smoke and ash: Oct 5, the newest UTC day mapped.
- 1Mexicali 63.8K
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
Baja California 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 |
|---|---|
| Ensenada | ≈ 9 µg/m³ |
| Rosarito | ≈ 14 µg/m³ |
| Tecate | ≈ 11 µg/m³ |
| Pórticos de San Antonio | ≈ 14 µg/m³ |
| Santa Isabel | ≈ 5 µg/m³ |
| La Joya | ≈ 14 µg/m³ |
| Rodolfo Sánchez Taboada | ≈ 6 µg/m³ |
| Terrazas del Valle | ≈ 10 µg/m³ |
| Villa del Prado 2da Sección | ≈ 10 µg/m³ |
| Ciudad Guadalupe Victoria | ≈ 6 µg/m³ |
| San Felipe | ≈ 4 µg/m³ |
| Lázaro Cárdenas | ≈ 6 µg/m³ |
| Las Delicias | ≈ 10 µg/m³ |
| Puebla | ≈ 5 µg/m³ |
Bad-air episodes in Baja California
- Western United States and Mexico, December 202513 to 22 December 2025, 10 days27 cities172 µg/m³peak, Tijuana
- South-western United States and Mexico, December 2024 to January 202529 December 2024 to 2 January 2025, 5 days37 cities167 µg/m³peak, Phoenix
- Western United States and Mexico, December 202324 to 28 December 2023, 5 days32 cities83 µg/m³peak, Tijuana
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 Baja California, Mexico, PM2.5, this year to 7 Oct 2026, 01:00 UTC, smogrank.com/mx/region/baja-california?w=year.
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.