Air quality
Air quality in Madison today
Updated
Good (US AQI 36) Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. Model estimate for Sun, Oct 25, 9:00 pm (02:00 UTC).
Live AQI, PM2.5, PM10 and ozone for Madison, Wisconsin, United States, with a 48-hour forecast and the best time to be outside.
- US AQI now
- 36 Good
- PM2.5
- 17 µg/m³ 1.1× WHO 24-h guideline
- PM10
- 17 µg/m³
- Ozone
- 31 µg/m³
- Dominant pollutant
- ozone sub-index 36
- Best hour tomorrow
- 9:00 pm AQI 32
- European AQI
- 43
Air quality in Madison right now
Right now the modelled US Air Quality Index for Madison, Wisconsin, United States is 36, which falls in the "Good" band (up to 50). Air quality is satisfactory and poses little or no risk; a good time for outdoor activity.
The index is driven mainly by ozone, whose own sub-index is 36. Ozone usually peaks in the afternoon on sunny days and falls back after sunset.
PM2.5 is 17 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 31 µg/m³ (below the WHO 8-hour level of 100); nitrogen dioxide is 31 µg/m³ (above the 24-hour guideline of 25).
Also this hour: carbon monoxide 323 µg/m³.
NASA FIRMS shows 40 fire hotspots within 300 km in the last day (nearest about 138 km), but particle levels are not elevated enough to point to smoke right now.
Madison AQI forecast: next 48 hours
Over the next 24 hours the AQI is forecast to range from 32 around Mon 9:00 pm to 48 around Mon 8:00 am, staying "Good" throughout.
The following day is expected to be cleaner, averaging about 27 against 42 for the next 24 hours.
| Local time (America/Chicago) | US AQI | Category | PM2.5 µg/m³ | PM10 µg/m³ | Ozone µg/m³ |
|---|---|---|---|---|---|
| Sun 9:00 pm | 36 | Good | 16.8 | 17 | 31 |
| Mon 12:00 am | 38 | Good | 9.1 | 9 | 37 |
| Mon 3:00 am | 43 | Good | 6.7 | 7 | 47 |
| Mon 6:00 am | 46 | Good | 5.6 | 6 | 47 |
| Mon 9:00 am | 48 | Good | 3.8 | 4 | 53 |
| Mon 12:00 pm | 46 | Good | 2.6 | 3 | 62 |
| Mon 3:00 pm | 43 | Good | 3.3 | 4 | 67 |
| Mon 6:00 pm | 40 | Good | 3.1 | 4 | 63 |
| Mon 9:00 pm | 32 | Good | 2.1 | 2 | 60 |
| Tue 12:00 am | 29 | Good | 1.6 | 2 | 58 |
| Tue 3:00 am | 27 | Good | 1.3 | 2 | 57 |
| Tue 6:00 am | 26 | Good | 1.3 | 1 | 52 |
| Tue 9:00 am | 25 | Good | 2.8 | 3 | 44 |
| Tue 12:00 pm | 23 | Good | 7.8 | 8 | 50 |
| Tue 3:00 pm | 23 | Good | 10.1 | 10 | 71 |
| Tue 6:00 pm | 28 | Good | 9.5 | 10 | 72 |
| Tue 9:00 pm | 32 | Good | 8.1 | 9 | 68 |
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 Madison tomorrow
Between 6 am and 9 pm local time, the cleanest air tomorrow is forecast around 9:00 pm (AQI 32, Good) and the worst around 8:00 am (AQI 48). That is a swing of 16 points, so a run or walk around 9:00 pm is noticeably better.
Madison vs the rest of United States
Across 619 United States cities we track, the average US AQI right now is 52 (Moderate). Madison at 36 is 16 points cleaner than average.
It ranks 54 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 Madison
| City | Distance | US AQI | Category | PM2.5 µg/m³ |
|---|---|---|---|---|
| Janesville | 53 km | 33 | Good | 10.4 |
| Rockford | 93 km | 35 | Good | 8.4 |
| Waukesha | 95 km | 37 | Good | 11.5 |
| Milwaukee | 122 km | 43 | Good | 16.3 |
| Oshkosh | 126 km | 34 | Good | 9.5 |
| Kenosha | 140 km | 49 | Good | 15.1 |
| Zion | 146 km | 49 | Good | 15.1 |
| Elgin | 147 km | 54 | Moderate | 19.7 |
Model vs measured
The nearest measured PM2.5 reading is 4.2 µg/m³ from Sensor.Community (median of 3 sensors), centred about 5 km from the city centre. That is 12.6 µg/m³ below the model estimate of 17 µg/m³. Low-cost sensors can read high in humid air; reference monitors are more accurate but sparser.
Advice for sensitive groups
With the AQI at 36, there is no need for sensitive groups to change plans. People with asthma should still carry their reliever inhaler as usual.
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 Madison
Air quality elsewhere
Data: Open-Meteo Air Quality API, Copernicus Atmosphere Monitoring Service (CAMS), Sensor.Community, NASA FIRMS.