Worst air pollution Castro - San Francisco, today and tomorrow
Today (15 July): Air quality in Castro is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 8:00 AM (O3: 39.4/100).
Tomorrow (16 July 2026): Air quality in Castro is medium. AQI improves to medium; O3 decreases to medium; all other pollutants stay as today. Pollution peaks around 10:00 AM (O3: 41.0/100). Airmine updates local air quality forecasts four times daily.
For long term forecasts and maps, see the Airmine app
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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San Francisco's Castro records moderate urban air quality, with Market Street traffic and the neighbourhood's busy commercial character contributing local emissions in the valley between Twin Peaks and Dolores Heights. Bay breezes penetrating up Market Street from the Embarcadero provide periodic ventilation, and the elevated streets toward the Twin Peaks summit record noticeably cleaner conditions.
Today - 15 July | Pollution peaks at 08:00
AQI:
Fair
39.4/100
PM2.5 (fine particles):
Good
13.3/100
PM10 (coarse particles):
Good
8.2/100
NO2 (nitrogen dioxide):
Good
3.9/100
O3 (ozone):
Fair
39.4/100
SO2 (sulfur dioxide):
Good
1.7/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
2.2/100
PM1 (ultrafine particles):
Good
7.3/100
Levels show the poorest local air quality during the day
Tomorrow - 16 July | Pollution peaks at 10:00
AQI:
Medium
41.0/100
PM2.5 (fine particles):
Good
18.5/100
PM10 (coarse particles):
Good
9.0/100
NO2 (nitrogen dioxide):
Good
8.3/100
O3 (ozone):
Medium
41.0/100
SO2 (sulfur dioxide):
Good
1.7/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
1.9/100
PM1 (ultrafine particles):
Good
12.2/100
Other Landmarks in San Francisco
Sports venues in San Francisco
Frequently Asked Questions
Is air quality bad in Castro right now?
On 15 July 2026, overall air quality in Castro is fair. AQI is the main air quality indicator at 39.4/100. Pollution peaks around 8:00 AM (O3: 39.4/100).
Will air quality be worse tomorrow in Castro?
On 16 July 2026, air quality conditions in Castro will be better than today, with AQI forecast at medium at 41.0/100. Pollution peaks around 10:00 AM (O3: 41.0/100).
When is air pollution at its worst in Castro?
At Castro, air quality tends to follow San Francisco's broader seasonal rhythm. Typically, winter storms periodically reset air quality, keeping the cleanest stretch to the rainy months, while wildfire smoke season from July through October is the dominant concern, sometimes overwhelming other pollution sources for days at a time. Dry summer conditions with virtually no rain mean pollution and smoke can linger for extended stretches once they arrive.
Are air quality levels in Castro 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.
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Data provided by Airmine — Last update: 16 July 2026 at 10:33 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.
For long term forecasts and maps, see the Airmine app