Is the air quality good in Los Angeles?

On November 2, 2025, at 4 AM PT, Los Angeles, California, is experiencing poor air quality conditions due to a combination of urban emissions, regional vehicle traffic, and atmospheric stagnation (1).

The concentrations of nitrogen dioxide (NO2) and carbon monoxide (CO) are notably high, measured at 75 µg/m3 and 515 ppbv respectively (2)(3).

Air quality is dynamic and, like the weather, can change frequently. Los Angeles ranked 16th among the most polluted cities in the world on Sunday morning. Nearby cities Fresno, Mexicali are also impacted.

Click here for a real-time air quality map of Los Angeles.

While the air quality conditions on November 2 are unusually poor, it is important to keep in mind that the average PM2.5 concentration in 2024 for Los Angeles was 10 µg/m3. This corresponds to an AQI of 42, which falls into the “good” category and was 2 times the WHO annual guideline of 5 µg/m3.

Los Angeles, California was listed as the 16th most polluted major city on November 2, 2025 4 AM PT. Source: IQAir.

When will air quality improve in Los Angeles?

Air quality in Los Angeles is forcasted to improve gradually as atmospheric conditions shift, later in the day when wind speeds increase slightly, allowing for better dispersion of pollutants.

Hourly air quality forecast for Los Angeles, California on November 2, 2025 4 AM PT. Source: IQAir.

Map of air quality in Los Angeles, California on November 2, 2025 4 AM PT. Source: IQAir.

What is causing poor air quality in Los Angeles?

The main contributors to poor air quality in Los Angeles are:

High density of traffic emissions leading to elevated NO2 and CO levels.
Industrial pollution and localized urban sources releasing volatile compounds and aerosols.
Calm and sunny weather that does not promote the vertical or horizontal dispersion of pollutants.
Coastal upwelling and surrounding mountains create a wind shadow, inducing a shallow marine layer capped by a thermal inversion that traps pollutants over the basin.

How can I protect myself from poor air quality?