Air quality
Air quality in El Cajon today
Updated
Moderate (US AQI 56) Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. Model estimate for Sun, Oct 25, 7:00 pm (02:00 UTC).
Live AQI, PM2.5, PM10 and ozone for El Cajon, California, United States, with a 48-hour forecast and the best time to be outside.
- US AQI now
- 56 Moderate
- PM2.5
- 10 µg/m³ 0.7× WHO 24-h guideline
- PM10
- 12 µg/m³
- Ozone
- 82 µg/m³
- Dominant pollutant
- ozone sub-index 56
- Best hour tomorrow
- 10:00 am AQI 43
- European AQI
- 31
Air quality in El Cajon right now
Right now the modelled US Air Quality Index for El Cajon, California, United States is 56, which falls in the "Moderate" band (up to 100). Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors.
The index is driven mainly by ozone, whose own sub-index is 56. Ozone usually peaks in the afternoon on sunny days and falls back after sunset.
PM2.5 is 10 µg/m³, within the WHO 24-hour guideline of 15 µg/m³; PM10 is 12 µg/m³ against a guideline of 45; ozone is 82 µg/m³ (below the WHO 8-hour level of 100); nitrogen dioxide is 14 µg/m³ (below the 24-hour guideline of 25).
Also this hour: carbon monoxide 160 µg/m³.
NASA FIRMS shows 41 fire hotspots within 300 km in the last day (nearest about 19 km), but particle levels are not elevated enough to point to smoke right now.
El Cajon AQI forecast: next 48 hours
Over the next 24 hours the AQI is forecast to range from 43 around Mon 10:00 am to 58 around Mon 7:00 pm, from "Good" at best to "Moderate" at worst.
The following day is expected to be worse, averaging about 54 against 46 for the next 24 hours.
| Local time (America/Los_Angeles) | US AQI | Category | PM2.5 µg/m³ | PM10 µg/m³ | Ozone µg/m³ |
|---|---|---|---|---|---|
| Sun 7:00 pm | 56 | Moderate | 10 | 12 | 82 |
| Sun 10:00 pm | 44 | Good | 12.5 | 13 | 28 |
| Mon 1:00 am | 46 | Good | 11.6 | 12 | 17 |
| Mon 4:00 am | 47 | Good | 9.1 | 10 | 18 |
| Mon 7:00 am | 46 | Good | 7.7 | 8 | 13 |
| Mon 10:00 am | 43 | Good | 2.4 | 4 | 74 |
| Mon 1:00 pm | 44 | Good | 4.5 | 7 | 114 |
| Mon 4:00 pm | 46 | Good | 7.8 | 9 | 122 |
| Mon 7:00 pm | 58 | Moderate | 11.7 | 14 | 76 |
| Mon 10:00 pm | 48 | Good | 14.8 | 16 | 28 |
| Tue 1:00 am | 50 | Good | 18.1 | 19 | 15 |
| Tue 4:00 am | 52 | Moderate | 18.6 | 19 | 16 |
| Tue 7:00 am | 54 | Moderate | 17.7 | 18 | 8 |
| Tue 10:00 am | 56 | Moderate | 7.1 | 9 | 75 |
| Tue 1:00 pm | 57 | Moderate | 8.2 | 11 | 114 |
| Tue 4:00 pm | 58 | Moderate | 11.5 | 15 | 111 |
| Tue 7:00 pm | 59 | Moderate | 11.9 | 15 | 61 |
Every third hour of the CAMS forecast via Open-Meteo. US AQI uses rolling averages (24 h for particles, 8 h for ozone), so it moves more slowly than the hourly concentrations.
Best time to be outside in El Cajon tomorrow
Between 6 am and 9 pm local time, the cleanest air tomorrow is forecast around 10:00 am (AQI 43, Good) and the worst around 7:00 pm (AQI 58). That is a swing of 15 points, so a run or walk around 10:00 am is noticeably better.
El Cajon vs the rest of United States
Across 619 United States cities we track, the average US AQI right now is 52 (Moderate). El Cajon at 56 is about average.
It ranks 302 of 619 from cleanest to most polluted; the cleanest is Hilo (22) and the most polluted Springfield, PA (132).
For context, the median across 3,556 cities worldwide is 58.
Air quality in cities near El Cajon
| City | Distance | US AQI | Category | PM2.5 µg/m³ |
|---|---|---|---|---|
| Spring Valley, CA | 7 km | 50 | Good | 10.7 |
| Chula Vista | 21 km | 50 | Good | 10.7 |
| San Diego | 21 km | 63 | Moderate | 15.7 |
| Coronado | 24 km | 63 | Moderate | 15.7 |
| Tijuana | 33 km | 59 | Moderate | 14.3 |
| Escondido | 38 km | 55 | Moderate | 14.3 |
| Vista | 52 km | 55 | Moderate | 14.3 |
| Carlsbad | 54 km | 55 | Moderate | 14.3 |
Model vs measured
We found no measured PM2.5 sensor cell within 25 km of El Cajon, so the numbers on this page are model estimates. Models capture regional pollution well but can miss very local sources such as a busy road or a nearby fire.
Advice for sensitive groups
At 56, most people are fine outdoors. If you are unusually sensitive to ozone, keep long or intense workouts to the cleaner hours shown above.
What the US AQI numbers mean
| US AQI | Category | What it means |
|---|---|---|
| 0-50 | Good | Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. |
| 51-100 | Moderate | Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. |
| 101-150 | Unhealthy for Sensitive Groups | People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors. |
| 151-200 | Unhealthy | Everyone should reduce prolonged or heavy exertion outdoors; sensitive groups should avoid it and keep windows closed. |
| 201-300 | Very Unhealthy | Health alert: everyone should avoid prolonged or heavy exertion outdoors, and sensitive groups should stay indoors. |
| 301-500 | Hazardous | Emergency conditions: everyone should avoid all outdoor physical activity and stay indoors with filtered air if possible. The scale tops out at 500; heavier dust or smoke is shown as 500. |
Values on this page are modelled by CAMS (Copernicus) and served by Open-Meteo; they are estimates for the area around the city centre, not readings from an official monitor.
Nearby cities
More for El Cajon
Air quality elsewhere
Data: Open-Meteo Air Quality API, Copernicus Atmosphere Monitoring Service (CAMS), NASA FIRMS.