Right now: San Diego is at 61, moderate.
Is the air safe to breathe in San Diego today?
In San Diego, BreatheCheck reads 61 as Go. The cutoffs: go below 101, keep it short and easy from 101 to 150, move it indoors above 150. These are our own thresholds, drawn on the EPA bands — EPA itself classifies 101–150 as Unhealthy for Sensitive Groups and does not tell you how long to stay out.
Go AQI 0–100
Normal outdoor plans. No change needed.
Short & unloaded AQI 101–150
A 20-minute dog walk, not a 2.5-hour run. Keep it brief and easy.
Don’t go AQI 151+
Move it indoors. Above 200 that becomes everyone, not just sensitive groups.
Above 200 this stops being a personal call: everyone indoors.
Duration and intensity are two separate dials
| Under 20 min | 20–60 min | Over an hour | |
|---|---|---|---|
| Easy | Go | Go | Go |
| Moderate | Go | Go | Go |
| Hard | Go | Go | Go |
Go Every combination lands the same way at this reading — a hard hour is no different from an easy twenty minutes. The two dials separate above 80.
Where people actually draw the line
At 61, this reading is past Asthmatic runner 's line.
All the thresholds people reported, and who reported them
- 60 Asthmatic runnerone runner’s own 156-run log
- 75–100 Daycare / schoolparents and staff in one r/toddlers thread, Aug 2025 — not a published rule
- 100 Parentcommunity-reported, escalating at 150 and 200
- 110 Runnercommunity-reported
If you’re staying in, filter the room you’re actually in
Why a coastal monitor is the county's best case
A coastal station reports the best-ventilated air San Diego County has, and the county is larger and less uniform than that reading admits.
The structure governing everything is the inversion. A subsidence inversion caps the depth available for mixing through much of the year, while the Peninsular Ranges wall the basin off to the east. A good deal of the ozone measured here was not made here: California Air Resources Board work on Los Angeles-to-San Diego transport describes South Coast basin air pushed offshore under mild Santa Ana conditions and then carried back inland by the following sea breeze. The inland valleys take the brunt of that, Alpine and El Cajon among them. The coastline usually does not.
Particles concentrate at the south end instead. The Portside Environmental Justice Neighborhoods — Barrio Logan, Logan Heights, Sherman Heights and west National City — sit between two working marine terminals and Interstate 5, and were nominated under California’s AB 617 community program for exactly that stack of ship, rail, cargo-handling and truck diesel. Research has additionally linked the Tijuana River, which carries untreated sewage north across the border, to airborne contaminants in the South Bay.
The American Lung Association’s 2026 State of the Air ranked the San Diego–Chula Vista–Carlsbad metro area seventh worst in the country for ozone and fifth worst for year-round particle pollution. Those two problems do not sit in the same place: the ozone peaks inland, the particles at the border end.
Where this number sits
Of the 121 US metros reporting to us right now, San Diego is number 9 and number 3 of the 12 we track in California. The pollutant driving it today is PM2.5.
Nearby metros we also measure, and what they read at the same hour:
- Irvine, CA — 77 miles away, AQI 46
- Riverside, CA — 86 miles away, AQI 73
- Anaheim, CA — 89 miles away, AQI 46
- Long Beach, CA — 94 miles away, AQI 50
Where this reading comes from
AirNow’s San Diego Coast reporting area, about 7.5 miles from the metro centre.
What has air quality in San Diego actually been?
4 of the 30 days we have recorded so far went above AQI 100.
| Date | Daily max AQI | EPA band | Hours read |
|---|---|---|---|
| 63 | Moderate | 22 | |
| 61 | Moderate | 23 | |
| 67 | Moderate | 23 | |
| 57 | Moderate | 23 | |
| 100 | Moderate | 23 | |
| 146 | Unhealthy for Sensitive Groups | 22 | |
| 152 | Unhealthy | 23 | |
| 162 | Unhealthy | 23 | |
| 79 | Moderate | 23 | |
| 55 | Moderate | 23 | |
| 51 | Moderate | 23 | |
| 52 | Moderate | 24 | |
| 53 | Moderate | 23 | |
| 62 | Moderate | 23 | |
| 72 | Moderate | 23 | |
| 72 | Moderate | 23 | |
| 65 | Moderate | 23 | |
| 66 | Moderate | 22 | |
| 63 | Moderate | 23 | |
| 59 | Moderate | 23 | |
| 68 | Moderate | 23 | |
| 62 | Moderate | 24 | |
| 65 | Moderate | 23 | |
| 62 | Moderate | 23 | |
| 69 | Moderate | 23 | |
| 70 | Moderate | 23 | |
| 69 | Moderate | 23 | |
| 61 | Moderate | 23 | |
| 165 | Unhealthy | 26 | |
| 51 | Moderate | 6 — partial day |
Questions about San Diego
What is the air quality in San Diego right now?
Which monitor does this number come from?
How does San Diego compare with metros nearby?
Does this include pollen?
Put this number in context
Updated