Worst air pollution San Francisco, today and tomorrow
Today (9 August): Air quality in San Francisco is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 4:00 AM (O3: 23.1/100).
Tomorrow (10 August 2026): Air quality in San Francisco is fair. All pollutants stay as today. Pollution peaks around 4:00 AM (O3: 24.6/100). Airmine updates local air quality forecasts four times daily.
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Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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San Francisco in Sonora reflects the flat Sonoran Desert border corridor position, with vehicle traffic on surrounding roads and the agricultural and border trade character contributing modest local sources. Windblown Sonoran Desert dust contributes elevated PM10, while the flat desert terrain allows reasonable dispersal and the area generally maintains moderate to good northwestern Mexican Sonoran Desert border readings throughout most of the year.
Today - 9 August | Pollution peaks at 04:00
AQI:
Fair
23.1/100
PM2.5 (fine particles):
Good
11.1/100
PM10 (coarse particles):
Good
11.3/100
NO2 (nitrogen dioxide):
Good
0/100
O3 (ozone):
Fair
23.1/100
SO2 (sulfur dioxide):
Good
0/100
CO (carbon monoxide):
Good
0/100
HCHO (formaldehyde):
Good
0.9/100
PM1 (ultrafine particles):
Good
3.1/100
Levels show the poorest local air quality during the day
Tomorrow - 10 August | Pollution peaks at 04:00
AQI:
Fair
24.6/100
PM2.5 (fine particles):
Good
8.8/100
PM10 (coarse particles):
Good
10.8/100
NO2 (nitrogen dioxide):
Good
0/100
O3 (ozone):
Fair
24.6/100
SO2 (sulfur dioxide):
Good
0/100
CO (carbon monoxide):
Good
0/100
HCHO (formaldehyde):
Good
0.8/100
PM1 (ultrafine particles):
Good
3.4/100
Frequently Asked Questions
Is air quality bad in San Francisco right now?
On 9 August 2026, overall air quality in San Francisco is fair. AQI is the main air quality indicator at 23.1/100. Pollution peaks around 4:00 AM (O3: 23.1/100).
Will air quality be worse tomorrow in San Francisco?
On 10 August 2026, air quality conditions in San Francisco will be similar to today, with AQI forecast at fair at 24.6/100. Pollution peaks around 4:00 AM (O3: 24.6/100).
When is air pollution at its worst in San Francisco?
In San Francisco, road traffic as well as farming and agricultural processing are the main local sources, with conditions worsening when dry spells bring strong winds. These wind events can carry dust in from the surrounding arid landscape. This is most noticeable during spring and autumn wind events.
Are air quality levels in San Francisco based on measurements or forecasts?
It is forecasts derived by downscaling forecasts provided by EU’s Copernicus Atmosphere Monitoring Service (CAMS) by taking into account local conditions such as traffic patterns. CAMS bases its forecast on satellite measurements of particles and chemical compounds in the atmosphere. Airmine’s services were developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team.
Why doesn’t the forecast always reflect wildfire impacts?
Airmine’s forecast uses CAMS (Copernicus Atmosphere Monitoring Service) as its background atmospheric model. While CAMS includes wildfire emissions, these are derived from satellite observations and are not available in real time. During rapidly evolving wildfire events, there may therefore be a delay before increased emissions are incorporated into the model. As a result, the forecast may temporarily underestimate PM₂.₅ and other pollutants associated with wildfire smoke.
During rapidly evolving wildfire events, CAMS may lag by approximately 1–2 days before increased wildfire emissions are fully represented, which can lead to temporary underestimation of PM₂.₅ concentrations in Airmine’s forecast.
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Data provided by Airmine — Last update: 9 August 2026 at 20:27 CEST (Data is updated four times daily.)
This forecast is produced independently using Airmine's own atmospheric data and models.
Unless explicitly made clear, the content on this site has not been paid for by external organisations and is Airmine's sole responsibility.
Disclaimer: Forecasts are provided for informational purposes only and should not be relied upon as medical advice. Actual pollen and air quality conditions may vary from the forecast. If you have allergies, asthma, or another medical condition, consult a healthcare professional. Please see our Terms of Service for important information about limitations of liability.
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