Smoke today in Belterra
Today the average level of fine particles (PM2.5) in Belterra is 41 µg/m³, 2.7 times the WHO daily guideline (15 µg/m³). The peak of the coming days arrives on Sunday 8 at 21:00, with 65 µg/m³. It most likely comes mainly from this fire: Uruará fire, 27 September 2026, 92 km to the east (65 % of the upwind weight).
The next 4 days, hour by hour
Hourly forecast of fine particles in the Belterra cell, coloured by the WHO steps. The numbered green bands are the windows with the least smoke.
Where it most likely comes from
At 04:00 on Thursday 5, air reaches Belterra at 850 hPa (about 1,500 m) from the east, at 24 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 5 Nov 2026, 02:42 UTC
Candidates
Upwind fires within 250 km, ranked by their weight in the smoke arriving at that hour.
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1Most likely: Uruará fire, 27 September 202665 %46,883 ha · since 27 September 2026 · about 35 hotspots and 826 MW FRP in 24 h inside its box · 92 km to the eastOpen the fire page
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2Scattered hotspots without a fire page14 %22 hotspots and 207 MW FRP in 24 h · the nearest 46 km to the east · outside any active fire page
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3Santarém fire, September 202611 %159,758 ha · since 7 September 2026 · about 10 hotspots and 131 MW FRP in 24 h inside its box · 80 km to the eastOpen the fire page
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4Mojuí dos Campos fire, 28 September 20263 %18,001 ha · since 28 September 2026 · about 3 hotspots and 21 MW FRP in 24 h inside its box · 25 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 · Thursday 510:00–12:0015 µg/m³ on average · ×1.0 the WHO guideline
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2 · Friday 610:00–12:0022 µg/m³ on average · ×1.4 the WHO guideline
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3 · Sunday 810:00–12:0021 µg/m³ on average · ×1.4 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. None falls below the guideline: these are the least bad hours, not clean ones.
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.