Air quality
Air quality in Niterói today
Updated
Moderate (US AQI 75) Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. Model estimate for Sun, Oct 25, 11:00 pm (02:00 UTC).
Live AQI, PM2.5, PM10 and ozone for Niterói, Rio de Janeiro, Brazil, with a 48-hour forecast and the best time to be outside.
- US AQI now
- 75 Moderate
- PM2.5
- 13 µg/m³ 0.9× WHO 24-h guideline
- PM10
- 16 µg/m³
- Ozone
- 58 µg/m³
- Dominant pollutant
- PM2.5 sub-index 75
- Best hour tomorrow
- 9:00 pm AQI 52
- European AQI
- 36
Air quality in Niterói right now
Right now the modelled US Air Quality Index for Niterói, Rio de Janeiro, Brazil is 75, which falls in the "Moderate" band (up to 100). Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors.
The index is driven mainly by PM2.5, whose own sub-index is 75. 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 13 µg/m³, within the WHO 24-hour guideline of 15 µg/m³; PM10 is 16 µg/m³ against a guideline of 45; ozone is 58 µg/m³ (below the WHO 8-hour level of 100); nitrogen dioxide is 18 µg/m³ (below the 24-hour guideline of 25).
Also this hour: carbon monoxide 214 µg/m³.
Niterói AQI forecast: next 48 hours
Over the next 24 hours the AQI is forecast to range from 51 around Mon 11:00 pm to 75 around Sun 11:00 pm, staying "Moderate" throughout.
The following day is expected to be cleaner, averaging about 54 against 63 for the next 24 hours.
| Local time (America/Sao_Paulo) | US AQI | Category | PM2.5 µg/m³ | PM10 µg/m³ | Ozone µg/m³ |
|---|---|---|---|---|---|
| Sun 11:00 pm | 75 | Moderate | 13.2 | 16 | 58 |
| Mon 2:00 am | 71 | Moderate | 9.2 | 12 | 56 |
| Mon 5:00 am | 69 | Moderate | 6.4 | 9 | 51 |
| Mon 8:00 am | 67 | Moderate | 11.8 | 15 | 48 |
| Mon 11:00 am | 64 | Moderate | 8.4 | 12 | 61 |
| Mon 2:00 pm | 59 | Moderate | 8.5 | 12 | 63 |
| Mon 5:00 pm | 55 | Moderate | 9.9 | 15 | 55 |
| Mon 8:00 pm | 53 | Moderate | 11.5 | 18 | 50 |
| Mon 11:00 pm | 51 | Moderate | 11.8 | 17 | 41 |
| Tue 2:00 am | 52 | Moderate | 11.7 | 17 | 38 |
| Tue 5:00 am | 52 | Moderate | 12 | 17 | 28 |
| Tue 8:00 am | 53 | Moderate | 8.9 | 13 | 50 |
| Tue 11:00 am | 53 | Moderate | 13.4 | 19 | 87 |
| Tue 2:00 pm | 54 | Moderate | 14.2 | 20 | 90 |
| Tue 5:00 pm | 55 | Moderate | 13 | 18 | 64 |
| Tue 8:00 pm | 56 | Moderate | 19 | 26 | 35 |
| Tue 11:00 pm | 58 | Moderate | 15.8 | 21 | 27 |
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 Niterói tomorrow
Between 6 am and 9 pm local time, the cleanest air tomorrow is forecast around 9:00 pm (AQI 52, Moderate) and the worst around 6:00 am (AQI 68). That is a swing of 16 points, so a run or walk around 9:00 pm is noticeably better.
Niterói vs the rest of Brazil
Across 144 Brazil cities we track, the average US AQI right now is 49 (Good). Niterói at 75 is 26 points worse than average.
It ranks 137 of 144 from cleanest to most polluted; the cleanest is Caxias do Sul (23) and the most polluted Manaus (134).
For context, the median across 3,556 cities worldwide is 58.
Air quality in cities near Niterói
| City | Distance | US AQI | Category | PM2.5 µg/m³ |
|---|---|---|---|---|
| Rio de Janeiro | 8 km | 65 | Moderate | 15.6 |
| Duque de Caxias | 24 km | 65 | Moderate | 15.6 |
| São João de Meriti | 29 km | 65 | Moderate | 15.6 |
| Barra da Tijuca | 30 km | 65 | Moderate | 15.6 |
| Nilópolis | 33 km | 63 | Moderate | 11.6 |
| Belford Roxo | 33 km | 63 | Moderate | 11.6 |
| Nova Iguaçu | 38 km | 63 | Moderate | 11.6 |
| Petrópolis | 43 km | 51 | Moderate | 10.7 |
Model vs measured
We found no measured PM2.5 sensor cell within 25 km of Niterói, 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.
Advice for sensitive groups
At 75, most people are fine outdoors. If you are unusually sensitive to PM2.5, keep long or intense workouts to the cleaner hours shown above.
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 Niterói
Air quality elsewhere
Data: Open-Meteo Air Quality API, Copernicus Atmosphere Monitoring Service (CAMS).