Air quality index for Prague, as of (Europe/Prague). Values update hourly — see this page for the current reading and hourly forecast. Today's peak: AQI 78 at 19:00 local time.

airindex·today

Air Quality in Prague

Prague is at today's forecast peak at the moment, AQI 77 (moderate). Today's main contributor is fine particulate matter (PM₂.₅), at 12 µg/m³.

Now, Oct 17at 20:00
77Moderate
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

By pollutant

  • PM₂.₅ fine particles · sets the index nowAQI 77
  • PM₁₀ coarse particlesAQI 26
  • O₃ ozoneAQI 22
  • NO₂ nitrogen dioxideAQI 8
  • CO carbon monoxideAQI 3
  • SO₂ sulfur dioxideAQI 2
Unusually sensitive people should consider reducing prolonged or intense outdoor activity

Modeled forecast data. AQI values come from atmospheric models (CAMS via Open-Meteo), not local monitoring stations. Readings can differ from ground-level conditions — for exact street-level values, consult an official air quality station near you. The forecast is calculated for a grid square, roughly 11 km across Europe and 45 km elsewhere, and air quality can vary within one square.

The next 48 hours

Hourly air quality index for Prague · Local time (GMT+2)

Today, Oct 17
Tomorrow, Oct 18
50
Peak 78 · 19:00
Peak 69 · 00:00
0:00
6:00
12:00
18:00
0:00
6:00
12:00
18:00

Good ≤ 50

Now
Show hourly data table
TimeAQIPM₂.₅µg/m³PM₁₀µg/m³O₃µg/m³NO₂µg/m³SO₂µg/m³COmg/m³°C
Today
00:0068192136152.40.347°
01:0068162037111.90.317°
02:0067192236111.70.297°
03:0067182330111.60.297°
04:00671623279.91.70.287°
05:00661622239.81.80.297°
06:0066192224111.90.306°
07:0066242717142.60.346°
08:0066232810185.00.365°
09:0066263020205.70.356°
10:0067293021175.30.338°
11:0067272931174.10.2711°
12:0068272940133.80.2613°
13:0069272843124.10.2614°
14:0070272854124.10.2515°
15:0071283059134.70.2516°
16:0073303258135.40.2715°
17:0075333554147.20.3115°
18:0077283741167.40.3414°
19:0078242634195.80.3113°
20:0077121233173.70.2413°
21:00757.51141122.90.2213°
22:00737.19.943113.00.2112°
23:00717.68.144123.10.1912°
Tomorrow
00:00696.37.0469.63.00.1811°
01:00685.87.8478.32.50.1711°
02:00675.97.2467.52.30.1611°
03:00666.37.1457.42.20.1611°
04:00656.47.1437.72.30.1611°
05:00646.97.7428.52.40.1711°
06:00647.48.4409.32.70.1711°
07:00637.88.737113.30.1810°
08:00617.98.733133.70.1810°
09:00607.78.531133.90.1810°
10:00587.99.234113.40.1711°
11:00568.09.234112.90.1712°
12:00558.49.1389.22.60.1712°
13:00539.711427.82.50.1713°
14:00521112466.32.40.1814°
15:00501113495.71.60.1814°
16:00471112506.01.30.1914°
17:00441115517.01.50.2215°
18:00401416479.32.00.2614°
19:0038192143122.60.2913°
20:0037242641133.50.3212°
21:0039232546133.70.3111°
22:0042232448113.70.2811°
23:00452326499.03.10.2710°

Today at a glance

Worst hour
19:00
peaks at AQI 78
Tomorrow
Much the same, peak 69
peak at 00:00

The week, hour by hour

Little changes tomorrow — the forecast peak is AQI 69 (moderate) around 00:00. The whole 5-day outlook sits in the moderate band, with daily peaks from AQI 60 to AQI 78 and Saturday the highest.

Each cell is one forecast hour, coloured by air quality band. A ring marks the day's worst hour. The blue ring marks the current hour.

TodayOct 17
Peak 78 at 19:00
Fog16° / 5°
SunOct 18
Peak 69 at 00:00
Overcast15° / 10°
MonOct 19
Peak 67 at 18:00
Overcast13° / 8°
TueOct 20
Peak 64 at 00:00
Overcast16° / 5°
WedOct 21
Peak 60 at 00:00
Light rain14° / 7°

Pollutants right now

Every pollutant on the same AQI scale as the big number above. The index only ever equals the worst score — pollutants don't add up.

050100150+
PM₂.₅fine particles · sets the index now
77
PM₁₀coarse particles
26
O₃ozone
22
NO₂nitrogen dioxide
8
COcarbon monoxide
3
SO₂sulfur dioxide
2
GoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardous

The colors cover a wide area, not a street. The forecast works in squares of roughly 11 km across Europe and 45 km elsewhere, so the air where you actually are can differ from the shade under the city.

Check air quality in: Donaustadt · Wałbrzych · Pilsen · Chemnitz · Bratislava

About Prague

CountryCzechia, Prague
TimezoneEurope/Prague (UTC+2)
Coordinates50.09° N, 14.42° E
Population≈ 1.17M

Air quality in Prague — common questions

What is the air quality in Prague right now?

The current air quality index (AQI) in Prague is 77 (Moderate). Today's forecast peak is AQI 78 (Moderate) at 19:00 local time, and tomorrow's forecast peak is AQI 69. These values come from the CAMS forecast model, not from a local monitoring station.

When is air quality expected to be worst in Prague today?

Today's forecast puts the highest AQI in Prague at 19:00 in the evening, reaching 78. The largest contributor right now is PM₂.₅. Air quality shifts through the day with traffic, wind, how well the air mixes and sunlight, so the hourly chart above shows the pattern for today and tomorrow.

What will the air quality be in Prague tomorrow?

Tomorrow's forecast peak for Prague is AQI 69 (Moderate) around 00:00 local time, much the same as today's peak of 78. A next-day forecast is less certain than today's, so check back in the morning for the updated hourly curve.

Which pollutants drive the AQI in Prague today?

The air quality index in Prague is set by PM₂.₅ right now. The modelled level this hour is 12 µg/m³, within the World Health Organization's 2021 guideline of 15 µg/m³. The others follow: PM₁₀ (AQI 26), O₃ (AQI 22), NO₂ (AQI 8), CO (AQI 3), and SO₂ (AQI 2).
Pollutant levels in Prague at the current hour
PollutantSub-indexLevelWHO 2021Vs guideline
PM₂.₅7712 µg/m³15 µg/m³ (24h)0.8×
PM₁₀2612 µg/m³45 µg/m³ (24h)0.3×
O₃2233 µg/m³100 µg/m³ (8h)0.3×
NO₂817 µg/m³25 µg/m³ (24h)0.7×
CO30.24 mg/m³4 mg/m³ (24h)0.1×
SO₂23.7 µg/m³40 µg/m³ (24h)0.1×
The overall AQI is the highest of the six sub-indices, so the pollutant with the highest sub-index is the one setting the number shown on this page. Sub-indices are computed over the EPA's averaging periods, while the levels are modelled values for the current hour.

Is air quality improving in Prague this week?

Over the 5-day forecast, daily peak AQI in Prague falls from 78 to 60. These are peak values: each day still has cleaner and dirtier hours, which the chart above shows.

How is air quality forecast for Prague, Prague, Czechia?

Air quality for Prague is forecast with the Copernicus Atmosphere Monitoring Service (CAMS), operated by ECMWF. CAMS models hourly levels of PM2.5, PM10, ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide. Prague lies at 50.1° N in the Northern Hemisphere, which sets the seasonal pattern of sunlight that drives much of the chemistry behind these pollutants. AQI values on this page use the US EPA scale.
About the Air Quality Index

What is the Air Quality Index (AQI)?

The Air Quality Index (AQI) is a tool developed by the U.S. Environmental Protection Agency (EPA) to communicate how clean or polluted the air is and what health effects may be of concern. The AQI runs from 0 to 500 and is divided into six color-coded categories: Good, Moderate, Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, and Hazardous.

How do I read the AQI values?

Lower AQI values mean cleaner air. An AQI of 0–50 (green) is Good, 51–100 (yellow) is Moderate, 101–150 (orange) is Unhealthy for Sensitive Groups, 151–200 (red) is Unhealthy, 201–300 (purple) is Very Unhealthy, and 301–500 (maroon) is Hazardous. When the AQI exceeds 100, air quality is considered unhealthy — at first for sensitive groups, then for everyone as the AQI rises.

Who are the sensitive groups?

Sensitive groups include people with heart or lung disease, older adults, children and teenagers, people who are pregnant, and people who are active outdoors. These groups are more likely to be affected when air quality is poor. If you are in a sensitive group, you can reduce your exposure by taking fewer and shorter outdoor walks when the AQI is elevated.

Which pollutants are measured?

The AQI covers five major pollutants regulated under the Clean Air Act: ground-level ozone (O₃), particle pollution (PM₂.₅ and PM₁₀), carbon monoxide (CO), sulfur dioxide (SO₂), and nitrogen dioxide (NO₂). An AQI value is calculated for each pollutant, and the highest value determines the overall AQI.

Where does the air quality data come from?

The hourly air quality data comes from the Copernicus Atmosphere Monitoring Service (CAMS), which provides global atmospheric composition forecasts. The data is accessed via Open-Meteo, which provides free, open-source weather and air quality APIs. The AQI categories and health guidance follow the EPA AirNow technical standard (EPA-454/B-24-002).

What are the health effects of poor air quality?

Poor air quality can cause respiratory issues, aggravate asthma and allergies, and increase the risk of cardiovascular problems. Fine particles (PM₂.₅) can penetrate deep into the lungs and bloodstream. The World Health Organization estimates that air pollution causes millions of premature deaths worldwide each year.

How often is the air quality forecast updated?

The CAMS air quality forecast is updated regularly using atmospheric models. Weather data such as temperature and cloud cover comes from Open-Meteo. The forecast provides up to 5 days of hourly air quality predictions.

AQI Levels (US EPA Standard)

Good (0–50) — Air quality is satisfactory — it's a great day to be active outside
Moderate (51–100) — Unusually sensitive people should consider reducing prolonged or intense outdoor activity
Unhealthy for Sensitive Groups (101–150) — Sensitive groups should reduce prolonged or intense outdoor activity. Take more breaks and watch for symptoms such as coughing or shortness of breath
Unhealthy (151–200) — Everyone should reduce prolonged or intense outdoor activity. Sensitive groups should avoid outdoor exertion. Consider moving activities indoors
Very Unhealthy (201–300) — Everyone should avoid prolonged or intense outdoor exertion. Sensitive groups should avoid all outdoor physical activity. Move activities indoors or reschedule
Hazardous (301–500) — Health warning — everyone should avoid all outdoor physical activity. Stay indoors and keep activity levels light. Follow tips for keeping particle levels low indoors

AQI categories and health guidance: EPA AirNow (EPA-454/B-24-002, May 2024). Air quality data: CAMS/Copernicus via Open-Meteo.