Air quality
Air quality in Philadelphia today
Updated
Unhealthy for Sensitive Groups (US AQI 130) People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors. Model estimate for Sun, Oct 25, 3:00 pm (19:00 UTC).
Live AQI, PM2.5, PM10 and ozone for Philadelphia, Pennsylvania, United States, with a 48-hour forecast and the best time to be outside.
- US AQI now
- 130 Unhealthy for Sensitive Groups
- PM2.5
- 16 µg/m³ 1.1× WHO 24-h guideline
- PM10
- 17 µg/m³
- Ozone
- 101 µg/m³
- Dominant pollutant
- PM2.5 sub-index 130
- Best hour today
- 3:00 pm AQI 130
- European AQI
- 41
Air quality in Philadelphia right now
Right now the modelled US Air Quality Index for Philadelphia, Pennsylvania, United States is 130, which falls in the "Unhealthy for Sensitive Groups" band (up to 150). People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors.
The index is driven mainly by PM2.5, whose own sub-index is 130. Fine and coarse particles come from traffic, heating, industry, dust and smoke; they build up on calm nights and clear when wind or rain arrives.
PM2.5 is 16 µg/m³, 1.1 times the WHO 24-hour guideline of 15 µg/m³; PM10 is 17 µg/m³ against a guideline of 45; ozone is 101 µg/m³ (above the WHO 8-hour level of 100); nitrogen dioxide is 8.3 µg/m³ (below the 24-hour guideline of 25).
Also this hour: UV index 1.9, carbon monoxide 162 µg/m³.
Philadelphia AQI forecast: next 48 hours
Over the next 24 hours the AQI is forecast to range from 95 around Mon 12:00 pm to 133 around Sun 8:00 pm, from "Moderate" at best to "Unhealthy for Sensitive Groups" at worst.
The following day is expected to be cleaner, averaging about 77 against 116 for the next 24 hours.
| Local time (America/New_York) | US AQI | Category | PM2.5 µg/m³ | PM10 µg/m³ | Ozone µg/m³ |
|---|---|---|---|---|---|
| Sun 3:00 pm | 130 | Unhealthy for Sensitive Groups | 16.2 | 17 | 101 |
| Sun 6:00 pm | 131 | Unhealthy for Sensitive Groups | 31.5 | 33 | 67 |
| Sun 9:00 pm | 133 | Unhealthy for Sensitive Groups | 62.4 | 65 | 0 |
| Mon 12:00 am | 129 | Unhealthy for Sensitive Groups | 50.6 | 53 | 2 |
| Mon 3:00 am | 116 | Unhealthy for Sensitive Groups | 32 | 34 | 15 |
| Mon 6:00 am | 105 | Unhealthy for Sensitive Groups | 25.6 | 28 | 25 |
| Mon 9:00 am | 98 | Moderate | 27.9 | 30 | 26 |
| Mon 12:00 pm | 95 | Moderate | 18.9 | 22 | 69 |
| Mon 3:00 pm | 95 | Moderate | 12.8 | 14 | 107 |
| Mon 6:00 pm | 94 | Moderate | 16.7 | 17 | 81 |
| Mon 9:00 pm | 88 | Moderate | 19.6 | 20 | 30 |
| Tue 12:00 am | 78 | Moderate | 20.9 | 21 | 31 |
| Tue 3:00 am | 73 | Moderate | 19 | 19 | 42 |
| Tue 6:00 am | 70 | Moderate | 14.5 | 15 | 44 |
| Tue 9:00 am | 67 | Moderate | 11.5 | 12 | 39 |
| Tue 12:00 pm | 63 | Moderate | 6.5 | 7 | 60 |
| Tue 3:00 pm | 61 | Moderate | 7 | 8 | 71 |
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 Philadelphia today
Between 6 am and 9 pm local time, the cleanest air today is forecast around 3:00 pm (AQI 130, Unhealthy for Sensitive Groups) and the worst around 8:00 pm (AQI 133). The difference across the day is small, so timing matters little.
Philadelphia vs the rest of United States
Across 23 United States cities we track, the average US AQI right now is 78 (Moderate). Philadelphia at 130 is 52 points worse than average.
It ranks 22 of 23 from cleanest to most polluted; the cleanest is Phoenix (51) and the most polluted Springfield, PA (130).
For context, the median across 667 cities worldwide is 71.
Air quality in cities near Philadelphia
| City | Distance | US AQI | Category | PM2.5 µg/m³ |
|---|---|---|---|---|
| Springfield, PA | 14 km | 130 | Unhealthy for Sensitive Groups | 16.2 |
Model vs measured
We found no measured PM2.5 sensor cell within 25 km of Philadelphia, 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.
Wildfire smoke
PM2.5 is forecast to reach 63 µg/m³ in the next 24 hours while NASA satellites detected 42 fire hotspots within 300 km in the last day (nearest about 9 km away). Smoke is a likely contributor: keep windows closed, run an air purifier or HVAC filter, and check the fire map before heading out.
Advice for sensitive groups
At 130, children, older adults, pregnant people and anyone with asthma, COPD or heart disease should limit time outdoors, especially strenuous activity. A well-fitted N95/FFP2 mask cuts particle exposure; it does not filter ozone.
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 Philadelphia
Air quality elsewhere
Data: Open-Meteo Air Quality API, Copernicus Atmosphere Monitoring Service (CAMS), NASA FIRMS.