What is the cleanest city in the world by air quality?

Longyearbyen, Svalbard (Norway) ranks as the world's cleanest monitored city with a composite US AQI of 8 and PM2.5 of just 1.9 µg/m³ — well below the WHO guideline of 5 µg/m³. Other top contenders include Whitehorse (Canada), Yellowknife (Canada), and remote Pacific island capitals.

What does AQI mean and how is it calculated?

The US AQI (Air Quality Index) converts measured pollutant concentrations into a 0–500 scale. 0–50 is Good (green), 51–100 is Moderate, 101–150 is Unhealthy for Sensitive Groups, 151–200 is Unhealthy, and higher values are Very Unhealthy or Hazardous. This site uses a composite AQI calculated as the maximum AQI across PM2.5, PM10, NO2, ozone and CO for each city.

Which continent has the cleanest air overall?

Oceania and North America consistently rank as the continents with the cleanest air quality. Remote Pacific island nations (Palau, Tuvalu, Marshall Islands, Micronesia) record some of the lowest PM2.5 concentrations on Earth. In North America, cities in Canada's Yukon and Northwest Territories lead the global rankings.

What is a good PM2.5 level to live in?

The WHO 2021 annual guideline for PM2.5 is 5 µg/m³. Cities below this threshold offer the healthiest long-term air for residents. A US AQI of 0–50 (PM2.5 below 9 µg/m³) is classified as Good. For comparison, many European and North American cities with Good AQI average 5–15 µg/m³, while polluted Asian cities can exceed 50–100 µg/m³ annually.

Cleanest Cities in South America 2026

Cleanest Cities in South America 2026 — Air Quality Rankings

Top 22 Cleanest Cities in South America by Air Quality

#	City	Continent	AQI	PM2.5
1	Hanga Roa, Easter Island	South America	AQI 11	PM2.5 2.6 µg/m³
2	Stanley, Falkland Islands	South America	AQI 18	PM2.5 4.3 µg/m³
3	Cayenne, French Guiana	South America	AQI 22	PM2.5 5.3 µg/m³
4	Punta Arenas, Chile	South America	AQI 23	PM2.5 5.5 µg/m³
5	Paramaribo, Suriname	South America	AQI 30	PM2.5 7.2 µg/m³
6	Arica, Chile	South America	AQI 31	PM2.5 7.5 µg/m³
7	Iquique, Chile	South America	AQI 33	PM2.5 8 µg/m³
8	Natal, Brazil	South America	AQI 35	PM2.5 8.4 µg/m³
9	La Serena, Chile	South America	AQI 40	PM2.5 9.5 µg/m³
10	Fortaleza, Brazil	South America	AQI 40	PM2.5 9.5 µg/m³
11	Santa Marta, Colombia	South America	AQI 40	PM2.5 9.5 µg/m³
12	Montevideo, Uruguay	South America	AQI 42	PM2.5 10 µg/m³
13	Viña del Mar, Chile	South America	AQI 42	PM2.5 10 µg/m³
14	Florianópolis, Brazil	South America	AQI 43	PM2.5 10.2 µg/m³
15	Antofagasta, Chile	South America	AQI 44	PM2.5 10.5 µg/m³
16	Valparaíso, Chile	South America	AQI 44	PM2.5 10.5 µg/m³
17	Cartagena, Colombia	South America	AQI 44	PM2.5 10.5 µg/m³
18	Curitiba, Brazil	South America	AQI 46	PM2.5 11 µg/m³
19	Porto Alegre, Brazil	South America	AQI 48	PM2.5 11.5 µg/m³
20	Barranquilla, Colombia	South America	AQI 48	PM2.5 11.5 µg/m³
21	Buenos Aires, Argentina	South America	AQI 52	PM2.5 12.5 µg/m³
22	Rosario, Argentina	South America	AQI 54	PM2.5 13 µg/m³