Worst air pollution Castillo de San Marcos - St. Augustine, today and tomorrow
Today (16 July): Air quality in Castillo de San Marcos is fair. AQI, PM10, and O3 are fair; PM2.5, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 12:00 PM (O3: 29.8/100).
Tomorrow (17 July 2026): Air quality in Castillo de San Marcos is fair. PM10 decreases to good; all other pollutants stay as today. Pollution peaks around 1:00 PM (O3: 26.5/100). 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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St. Augustine's Castillo de San Marcos air quality benefits from the Matanzas Bay waterfront position, with consistent Atlantic and Intracoastal Waterway sea breezes providing reliable maritime ventilation around the oldest masonry fort in the continental US. Vehicle traffic on San Marco Avenue contributes modest local sources, while the bay's open water geometry and the Atlantic coastal proximity generally maintain the Castillo among St. Augustine's more moderately ventilated major historic attractions throughout most of the year.
Today - 16 July | Pollution peaks at 12:00
AQI:
Fair
29.8/100
PM2.5 (fine particles):
Good
19.2/100
PM10 (coarse particles):
Fair
27.5/100
NO2 (nitrogen dioxide):
Good
0.1/100
O3 (ozone):
Fair
29.8/100
SO2 (sulfur dioxide):
Good
2.6/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
0.8/100
PM1 (ultrafine particles):
Good
3.9/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 13:00
AQI:
Fair
26.5/100
PM2.5 (fine particles):
Good
15.6/100
PM10 (coarse particles):
Good
15.7/100
NO2 (nitrogen dioxide):
Good
0.1/100
O3 (ozone):
Fair
26.5/100
SO2 (sulfur dioxide):
Good
2.4/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
0.8/100
PM1 (ultrafine particles):
Good
3.4/100
Other Landmarks in St. Augustine
Frequently Asked Questions
Is air quality bad in Castillo de San Marcos right now?
On 16 July 2026, overall air quality in Castillo de San Marcos is fair. AQI is the main air quality indicator at 29.8/100. Pollution peaks around 12:00 PM (O3: 29.8/100).
Will air quality be worse tomorrow in Castillo de San Marcos?
On 17 July 2026, air quality conditions in Castillo de San Marcos will be similar to today, with AQI forecast at fair at 26.5/100. Pollution peaks around 1:00 PM (O3: 26.5/100).
When is air pollution at its worst in Castillo de San Marcos?
Castillo de San Marcos experiences the same seasonal air quality swings as the rest of St. Augustine. In short, daily summer storms tend to scrub the air clean before pollution can build up, whereas without the wet season's regular storms, dry-season smoke can linger for days at a time. Inland areas tend to see more smoke buildup than locations closer to the coast.
Are air quality levels in Castillo de San Marcos 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