SmogRank / History / City race
Cities in Brazil, worst air first, day by day
Each measured city's average over the 30 days to every day since January 2023, worst first. Find your own city to follow it through the race, or keep to one country.
The worst cities in Brazil for PM2.5 over the 30 days to 8 Jul 2026: Nilópolis 28.3 µg/m³, Duque de Caxias 19.1 µg/m³ and Barra da Tijuca 13.5 µg/m³.
- 1NilópolisRio de Janeiro28.3
- 2Duque de CaxiasRio de Janeiro19.1
- 3Barra da TijucaRio de Janeiro13.5
- 4ItaguaíRio de Janeiro13.3
- 5Rio de JaneiroRio de Janeiro10.7
- 6AcariRio de Janeiro9.8
Cities counted each day
A city's number is its average over the 30 days, shown only when 21 of them were measured (5 of 7 on the 7-day race), the same minimum as the 30- and 7-day boards. A city whose monitors go quiet fades out where it stood rather than sliding down, so a gap never reads as cleaner air. Some large countries are thin or missing because their monitors' licences don't allow reuse. How we rank.
Not covered: the government monitoring networks of China and Turkey, which publish only on their own websites; we are building the readers for them. Most cities there are missing from this board, not clean. Why.