California Air Quality Alert: Winter Temperature Inversions

Is the air quality good in California?

As of December 5, 2024, air quality is poor in many regions of California due to high levels of particulate matter (PM2.5) and ozone pollution.

Southern California is under air quality alerts, with advisories to limit outdoor activities due to potential respiratory health risks (1)(2). Areas affected by poor air quality include the Central Valley and parts of the South and East Bay areas (3)(4).

Where is air quality poor in California

Air quality is poor on December 5, 2024 in many Californian cities, including:

• Bakersfield
• Chico
• Los Angeles
• Merced
• Modesto
• Porterville
• Riverside
• Sacramento
• San Jose
• Stockton
• Turlock

Why is there an air quality alert in California?

Air quality alerts have been issued in parts of California due to a combination of factors, including temperature inversions, stagnant air masses, and ongoing pollution from vehicles, industrial activities, and wood burning. These conditions trap pollutants close to the ground, exacerbating smog and particulate pollution.

What is a temperature inversion?

A temperature inversion occurs when a layer of warm air traps cooler air near the ground. This phenomenon prevents pollutants from dispersing and leads to poor air quality. Winter temperature inversions are common in Southern California due to the region's geography, with valleys and basins creating conditions for pollutants to accumulate.

Are there any alerts in place?

Yes, there are air quality alerts and burn bans in effect for Southern California. The South Coast Air Quality Management District has prohibited wood burning in certain areas through at least midnight on Thursday (5). Residents are advised to stay indoors and use air purifiers to minimize exposure to pollutants.

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.