SmogRank / World / Brazil / Paraná / December 2025

Most unhealthy days in Paraná, Brazil, December 2025

10 cities in Paraná, Brazil ranked by their share of unhealthy days over the 31 days. The most unhealthy days: Colombo, Brazil, 0 of 22 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. Cities with the same share are ordered by more unhealthy days, then by the higher average.

← Colombo 0% 0.75%0
Every city in Paraná, Brazil ranked for December 2025, one column each, ranked by unhealthy days: height is the share of its measured days that were unhealthy, colour its average. Point at it to read a city; tap to open it.
  1. 1Colombo
    0%0 of 22
  2. 2Araucária
    0%0 of 31
  3. 3Guarapuava
    0%0 of 29
  4. 4Paranaguá
    0%0 of 27
  5. 5Ponta Grossa
    0%0 of 28
  6. 6Maringá
    0%0 of 22
  7. 6Curitiba
    0%0 of 31
  8. 8Francisco Beltrão
    0%0 of 25
  9. 9Londrina
    0%0 of 23
  10. 10União da Vitória
    0%0 of 27
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, December 2025 · All cities in Brazil, December 2025 · Paraná now

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SmogRank, most polluted cities in Paraná, Brazil by unhealthy days (PM2.5), December 2025: each city's share of its measured days with a daily mean over 35.4 µg/m³, cities measured on 22 or more of the 31 days. Monitor data from national networks via OpenAQ and the publishers listed at smogrank.com/sources. smogrank.com/br/region/parana/history/2025-12?by=days (accessed 11 Oct 2026). Some readings from Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); RMCAB (Secretaría Distrital de Ambiente, Bogotá); Love My Air (City and County of Denver), no reuse terms published.

Download top 10 by average (PNG)

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.