Is the air quality good in Southern California?
As of December 23, 2025, air quality across Southern California remains poor, with some areas experiencing “unhealthy” AQI levels and elevated PM2.5 concentrations. These conditions pose health risks, particularly to children, the elderly, and individuals with respiratory or heart conditions.
Several monitoring stations have recorded AQI readings above 150, triggering health advisories. Residents are urged to limit outdoor activities, keep windows closed, wear masks when outdoors, and use indoor air purifiers when possible.
Air quality map of Southern California on the night of December 22, 2025. Source: IQAir.
Which cities are affected by bad air quality in Southern California?
As of December 23, 2025, several major cities across California are reporting poor air quality. The most affected cities include:
Air quality conditions can change rapidly throughout the day. For a complete, real-time overview of pollution levels, see California air quality map.
When will the air quality improve in Southern California?
Short-term air quality improvements depend on weather, with stronger winds or rain helping to disperse pollutants. During winter, however, temperature inversions and stagnant air trap emissions near the ground, keeping pollution levels high for longer. As a result, air quality may remain elevated and fluctuate until conditions change.
What is causing poor air quality in Southern California?
California’s air quality often worsens in winter because pollutants become trapped near the ground under temperature inversions and stagnant air, especially in basins like the Central Valley and Los Angeles Basin, preventing normal dispersion. (1)
Residential wood burning for heating, vehicle and diesel emissions, and industrial combustion all contribute elevated levels of fine particulate matter during this season. (2)
How can I protect myself from poor air quality?
- Get a free air quality app for real-time air quality alerts and forecasts.
- Shut doors and windows and set the HVAC to recirculate mode.
- Contribute to your community’s outdoor air quality data.
- Stay indoors when air quality is poor; if you do need to go outdoors, wear a KN95/FFP2 mask.
- Run a high-performance air purifier to filter particles, gases, and other pollutants.
