SmogRank / World / Brazil / Rio de Janeiro / September 2023

Most unhealthy days in Rio de Janeiro, Brazil, September 2023

1 city in Rio de Janeiro, Brazil ranked by its share of unhealthy days over the 30 days. The most unhealthy days: Duque de Caxias, Brazil, 1 of 29 measured days. A city needs measurements on 70% of the days to be ranked.

Ranked by unhealthy days: the share of each city's measured days with a daily mean over 35.4 µg/m³ (US AQI 101+), Unhealthy for Sensitive Groups or worse on the US EPA's scale. Ties go to the higher average.

  1. 1Duque de Caxias
    1 of 29
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales

All cities in the world, September 2023 · All cities in Brazil, September 2023 · Rio de Janeiro now

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SmogRank, most polluted cities in Rio de Janeiro, Brazil, by unhealthy days, PM2.5, September 2023, smogrank.com/br/region/rio-de-janeiro/history/2023-09?by=days (accessed 7 Oct 2026).

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You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.