Smoke today in Prainha
Today the average level of fine particles (PM2.5) in Prainha is 17 µg/m³, 1.1 times the WHO daily guideline (15 µg/m³). The peak of the coming days arrives on Sunday 8 at 04:00, with 25 µg/m³. It most likely comes mainly from scattered hotspots upwind that are not part of any fire page (91 % of the weight), the nearest 59 km to the east. Among fires with a page, the one that weighs most is Almeirim fire, 9 October 2026, 119 km away (5 %).
The next 4 days, hour by hour
Hourly forecast of fine particles in the Prainha cell, coloured by the WHO steps. The numbered green bands are the windows with the least smoke.
Where it most likely comes from
At 10:00 on Friday 6, air reaches Prainha at 850 hPa (about 1,500 m) from the east, at 30 km/h. Move the hour on the strip above and the sector turns with the wind.
VIIRS hotspots from the last 24 hours; the latest at 6 Nov 2026, 00:00 UTC
Candidates
Upwind fires within 250 km, ranked by their weight in the smoke arriving at that hour.
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1Most likely: Scattered hotspots without a fire page91 %357 hotspots and 3,649 MW FRP in 24 h · the nearest 59 km to the east · outside any active fire page
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2Almeirim fire, 9 October 20265 %3,170 ha · since 9 October 2026 · about 16 hotspots and 130 MW FRP in 24 h inside its box · 119 km to the northeastOpen the fire page
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3Almeirim fire, 21 October 20264 %4,383 ha · since 21 October 2026 · about 11 hotspots and 76 MW FRP in 24 h inside its box · 70 km to the northeastOpen the fire page
There is no dispersion model behind this: it is an estimate. We add up the radiative power (FRP) of the last 24 hours of VIIRS hotspots lying against the wind at 850 hPa, weighted by distance. That is why we say “most likely” and show the whole list.
The 3 windows with the least smoke to air the house or go out
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1 · Friday 612:00–14:0010 µg/m³ on average · within the WHO guideline
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2 · Sunday 810:00–12:009 µg/m³ on average · within the WHO guideline
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3 · Monday 911:00–13:008 µg/m³ on average · within the WHO guideline
Between 7:00 and 22:00, future hours only, 2-hour blocks at least 4 hours apart. The WHO guideline is a 24-hour average: here it is only a reference.
The last time there was smoke like this
We are still gathering the history for this cell: the archive loads at night, a little at a time.
We do not give medical advice. To know what to do at these levels, follow the health authority: Ministério da Saúde. Our figures are a model forecast, not a measurement in your street.
If you see fire or smoke, call 193. Emergency number and official warnings
How this page works
- Air quality: Copernicus CAMS served by our own Open-Meteo instance, in the city’s 0.1° cell (CAMS Europe at 0.1° where it covers; elsewhere the coarser 0.4° global model). Refreshed every hour.
- Wind: ECMWF IFS at 0.25°, at 850 hPa (about 1,500 m, the height at which smoke usually travels) and at 10 m. The arrival direction is the vector mean of the previous 6 hours.
- Likely source: VIIRS hotspots from the last 24 hours within 250 km (150 km in Europe) and within 40° of the wind direction, weighted FRP × cos(angle) × e^(−distance/120 km). Each hotspot goes to the active fire page whose box contains it; if none does, it counts as a scattered hotspot. With less than 30 MW upwind no fire is named.
- Smoke episode: today’s average above the WHO guideline (15 µg/m³) and, in Europe, at least 10 µg/m³ of PM10 that CAMS attributes to wildfires; outside Europe, at least 30 MW of fires upwind. To speak of “this episode” in the history it takes 7 days or more above the guideline. Outside Europe, those fires must also add up to a weight of at least 100 (FRP × cos × e^(−d/120)), and if desert dust makes up 50 % or more of today's PM10 it is not counted as smoke.
- History: daily mean and maximum PM2.5 since August 2022 from our CAMS archive, stored per cell.
- Health: the reference is the 2021 WHO air quality guideline (24-h PM2.5: 15 µg/m³; interim targets 25, 37.5, 50 and 75). We give no medical advice of our own.
Sources. Air quality: Copernicus Atmosphere Monitoring Service (CAMS global and CAMS Europe) served by our own Open-Meteo instance, Open-Meteo.com data under CC BY 4.0. Wind: ECMWF IFS 0.25° via Open-Meteo.com (CC BY 4.0). Active fires: NASA FIRMS, VIIRS (Suomi NPP, NOAA-20 and NOAA-21). Fire pages: EFFIS and GWIS (Copernicus, European Commission). Reference: 2021 WHO air quality guidelines. Open-Meteo.com (CC BY 4.0) · CAMS · NASA FIRMS
Contains modified Copernicus Atmosphere Monitoring Service information (2026). Neither the European Commission nor ECMWF is responsible for any use that may be made of this information.