San Diego, CA Air Quality
Report & Trends
Analysis & History
The Verdict
This places San Diego, CA in the bottom 3% of US cities for air quality.
You are most likely to need an air purifier in July, when historical averages peak.
Health Recommendation
Sensitive groups should consider monitoring daily forecast apps significantly closer.
10-Year Annual PM2.5 Average
Analysis: Annual average Median AQI from 2015 to 2025.
Compared to national averages, San Diego, CA has a unique air quality profile driven by seasonal changes. Since 2015, wildfire smoke days have trended downward, signaling a positive shift in local air hygiene.
Seasonal Risk Calendar
The "Smoke Season" Calendar
Values represent historical Average Monthly AQI (PM2.5). Higher is worse.
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Common Questions
When is the worst time for air quality in San Diego, CA?
Based on 10 years of data, the worst months for air quality in San Diego, CA are: July (AQI 93.8), September (AQI 91.1), October (AQI 90.8). These months typically see the highest concentrations of PM2.5 due to smoke from fires hundreds of miles away.
Is it safe to move to San Diego, CA given the air quality?
Yes, but with caveats. San Diego, CA offers an incredible quality of life, but new residents should be aware of the "smoke season." Most homes in the area need robust air filtration systems to maintain safe indoor levels during these few weeks a year.
Is the air quality in San Diego, CA improving?
Yes. Our 10-year analysis shows a positive trend. Despite regional wildfire challenges, average particulate levels in San Diego, CA have decreased, likely due to favorable weather patterns and reduced local emissions.
Do I really need an air purifier in San Diego, CA?
Based on the 10-year analysis, absolutely. The levels of PM2.5 recorded during peak events are unsafe for indoor occupation without filtration. A CADR-rated purifier is considered essential appliance for San Diego, CA households.
How accurate is this data?
This report is built on official EPA Air Quality System (AQS) data. We aggregated daily summary files from 2014 to present to build these charts. Unlike real-time apps that estimate, this is the verified historical record.
Is San Diego, CA safe from other disasters?
Air quality is just one factor. Check our sister site for a complete analysis of tornado, hurricane, and flood risks.
Full Safety Report →Summary
Looking at the 10-year chart, the direction is undeniable. Cleaner air is possible, but it requires active management.