The 2022 World Air Quality Report covered in depth which countries and cities struggle with the greatest burden of poor air quality. These concerns are important to millions of people whose cardiac and respiratory health are at risk.
But there’s good news. The report also unveiled that people living in major cities all over the world enjoyed good annual average air quality. That’s important, and heartening, as large urban areas can be potent sources of endemic pollutants where millions of people work, live, and breathe every day.
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Learn about the state of air quality around the world.
In these five highlighted big cities, the annual average air PM2.5 was well under the World Health Organization’s (WHO) guideline of 5 micrograms per cubic meter (µg/m3) or less. IQAir’s annual air quality report highlights PM2.5 as the standard air quality indicator because it is widely recognized as the most harmful pollutant and because of its wide range of severe health consequences.
There were many small towns and cities with better air quality than these top five major cities. For instance, the cleanest air quality in the world was found in Arch Cape, Oregon, an unincorporated coastal town of less than 1,000 people with an average PM2.5 concentration of just 0.2 µg/m3. For this list, the selected cities have populations estimated at over 100,000 residents or greater.
5. Toowoomba, Australia: Wet weather cleans air
Two of the five least polluted cities in the world are in Australia. Toowoomba lies near the coast of Queensland, Australia, not far from Brisbane, and had an estimated population of 142,000 in 2021.
The city can experience smoke from brushfires, as it did during the historic Australian brush fires of 2019-2020. But the 2022 bushfire season – typically running from July to October in Queensland - witnessed a La Niña atmospheric phenomenon which kept the region wetter than in previous years (1). Rainy, windy weather can help air quality by dispersing pollutants, and this phenomenon did exactly that in Toowoomba in 2022.
Toowoomba’s air quality was good on Monday, March 13, 2023. Source: IQAir.
4. Petropavl, Kazakhstan: Cleaner with less energy use
In the far north of Kazakhstan, near its border with Russia, is the city of Petropavl (known locally as Kyzylzhar, or “Red Cliff”). Home to nearly a quarter million people, the city’s annual average concentration of PM2.5 was 2.3 µg/m3.
Petropavl air quality on March 13. Source: IQAir.
This was unusually great air quality for Central Asia. The region typically endures exceptionally poor air quality in winter due to emissions from old vehicles, the widespread use of brown (lignite) coal for home heating and cooking, and temperature inversions. However, the city’s forested topography isn’t as subject to inversions as it is not in a valley nor near mountains.
The correlation between air pollutant concentrations with meteorological parameters in this region is low.
Though Petropavl relies heavily on coal, the coal plant Petropavlovsk CHPP-2 only has two of its three chimneys functioning due to a chimney collapse on March 20, 2022. It’s uncertain if the plant has produced less emissions.
There was less snow observed in the city in 2022 in comparison to 2021. It’s possible that reduced energy use can help account for the good air quality.
2. and 3: Wellington, New Zealand and Kupang, Indonesia: Island cities with the same air quality
Two cities were tied as the second cleanest: Wellington, New Zealand and Kupang, Indonesia.
Wellington is the capital of New Zealand with an estimated 419,000 people. In recent years, the city has demonstrated a commitment to clean air by transitioning its bus network from diesel to electric. The regional environmental team released a report in October 2022 that revealed a 28 percent drop in diesel air particulate air pollution and an 18 percent decline in nitrogen dioxide between 2021 and 2022 (2).
The World Air Quality report confirmed an air quality improvement. The city showed a 45 percent improvement in PM2.5 annual average concentration, dropping from 4.2 µg/m3 to just 2.3 µg/m3 between 2021 and 2022.
Wellington, New Zealand had good air quality on March 13. Source: IQAir.
Kupang, Indonesia is another island city with a similar population of about 434,000. It had the same air quality as Wellington, New Zealand in 2022, an annual average PM2.5 concentration of 2.3 µg/m3. The capital of East Nusa Tenggara province, the city is on the island of Timor, which Indonesia shares with the country Timor-Leste.
The city regularly sees a great deal of precipitation throughout the year, which can have a positive impact on keeping pollutants out of the air.
Kupang, Indonesia had good air quality on March 13. Source: IQAir.
Kupang is low-lying and there are nearby hills in the southwest. Hilly and mountainous topography can block wind, reducing the ability for pollutants to disperse. However, only 10 percent of the city’s wind during 2022 flowed in the direction of the hills, which made it easier for accumulated pollutants to leave the area.
Kupang’s sources of pollution can include wildfires. There were fewer wildfires impacting the city in 2022 than in previous years.
1. Cockburn, Australia: Suburb with the best air quality
The second Australian city on the list is also the least polluted major city in the world. Cockburn, with an estimated population of 114,000, is just south of Perth. The suburb experienced an annual average concentration of PM2.5 of 2 µg/m3.
Perth and Cockburn typically have good air quality year-round, though this can be affected by vehicle emissions and nearby brushfire smoke. Again, we see the connection between moisture and better air quality; because the region saw a great deal more rainfall than in previous years – closer to the city’s normal levels of precipitation - there were no largescale brushfires.
Those were the five cleanest big cities in the world- but how did other areas of the world fare?
In Northern America, the major city with the cleanest air quality was Las Vegas, Nevada. Though the city has been subjected to sand and dust storms in the past, the city met the recommended WHO guideline and only experienced an annual average PM2.5 concentration of 4 µg/m3 in 2022.
The cleanest major city in Latin America and the Caribbean was also in the United States. The Commonwealth of Puerto Rico’s capital city, San Juan had an annual average PM2.5 concentration of 3.3 µg/m3. Europe’s cleanest big city, Reykjavik, Iceland, had that same annual average PM2.5 concentration of 3.3 µg/m3.
The biggest cities in East Asia, Africa, and West Asia did not meet the WHO guideline, though Japan's Hokkaido island city of Kushiro came close with an annual average PM2.5 concentration of 5.4 µg/m3. In Africa, Cape Town, South Africa experienced an annual average PM2.5 concentration of 6.7 µg/m3.
Some major cities naturally benefit from geography or prevailing meteorological conditions in mitigating poor air quality. But the key to enjoying and keeping safe, breathable air is to control source pollutants by reducing our reliance on dirty energy sources like coal and diesel and transitioning towards greener energy choices.
As Wellington did with its bus fleet, city governments can set localized, effective policies to remove pollutant sources. As individuals, we can advocate for policy change and stay informed about air quality conditions.
You can always know your air quality in real time by downloading a free air quality app today.