Worst air pollution El Cajon, today and tomorrow
Today (15 July): Air quality in El Cajon is fair. PM2.5 and O3 are fair; AQI and PM10 are medium; NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 8:00 AM (PM10: 45.7/100).
Tomorrow (16 July 2026): Air quality in El Cajon is fair. AQI worsens to fair; PM10 increases to fair; all other pollutants stay as today. Pollution peaks around 6:00 AM (PM10: 39.1/100). 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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El Cajon's air quality reflects the San Diego County inland valley position, with vehicle emissions from SR-8 and the surrounding urban commercial character creating warmer, more stagnant conditions than the coastal San Diego suburbs. The surrounding Cuyamaca Mountains and Viejas Ridge create topographic enclosure, while the valley position means El Cajon experiences higher ozone concentrations than coastal San Diego and occasional Santa Ana wind events can worsen conditions.
Today - 15 July | Pollution peaks at 08:00
AQI:
Medium
45.7/100
PM2.5 (fine particles):
Fair
33.7/100
PM10 (coarse particles):
Medium
45.7/100
NO2 (nitrogen dioxide):
Good
4.1/100
O3 (ozone):
Fair
26.9/100
SO2 (sulfur dioxide):
Good
8.6/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
1.0/100
PM1 (ultrafine particles):
Good
5.9/100
Levels show the poorest local air quality during the day
Tomorrow - 16 July | Pollution peaks at 06:00
AQI:
Fair
39.1/100
PM2.5 (fine particles):
Fair
23.5/100
PM10 (coarse particles):
Fair
39.1/100
NO2 (nitrogen dioxide):
Good
5.6/100
O3 (ozone):
Fair
28.0/100
SO2 (sulfur dioxide):
Good
9.5/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
0.9/100
PM1 (ultrafine particles):
Good
4.9/100
Pollen forecast in El Cajon
View pollen forecastFrequently Asked Questions
Is air quality bad in El Cajon right now?
On 15 July 2026, overall air quality in El Cajon is fair. PM2.5 is the main pollutant at 33.7/100. Pollution peaks around 8:00 AM (PM10: 45.7/100).
Will air quality be worse tomorrow in El Cajon?
On 16 July 2026, air quality conditions in El Cajon will be similar to today, with AQI forecast at fair at 39.1/100. Pollution peaks around 6:00 AM (PM10: 39.1/100).
When is air pollution at its worst in El Cajon?
El Cajon experiences a distinct seasonal swing in air quality — the shortest stretch of clean air usually falls in the wetter winter months, whereas summer sunshine and heat drive some of the worst ozone readings in the country. The mountains ringing the basin can trap pollution close to the ground for days when winds are calm.
Are air quality levels in El Cajon 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