But, surprise, one of the cleanest cities in Iran is Tehran—though it is among the most polluted in the world.
The World Health Organization (WHO), a specialized agency of the UN, issued its first tabulation Monday of air pollution in 1,082 cities. It used one measure—the volume of particulate matter in the air with a diameter of 10 microns or less per cubic meter, known in the pollution business as PM10. There are many other elements of air pollution, but PM10 measures one of the most harmful. Particulate matter is largely sulfur dioxide and nitrogen dioxide from auto exhausts and industry.
Low quality gasoline and unregulated industry are suspected of being the major causes of PM10s in Iran.
PM10s are major causes of respiratory problems for humans.
The WHO tabulation ranks cities by the annual mean volume of PM10. meaning that a particular bad day or season is averaged out over the year, giving a better idea of the long-term impact on residents.
The WHO tabulation shows that the most polluted city in the entire world—Number 1,082 on the list—is Ahvaz with 372 microns of PM10. What’s more, Ahvaz has no competition for that ranking. The second dirtiest air in the world is found in Ulan Bator, the capital of Mongolia, which recorded 279 microns or only 75 percent as much as Ahvaz.
Of the dirtiest 10 cities in the world, four are in Iran—Ahvaz, Sanandaj, Kermanshah and Yasuj.
Tehran ranked 1,001st in the world of dirtiness. But within Iran it was one of the least dirty, ranking 15th of the 18 cities reporting.
At the other end of the scale, Whitehorse, capital of the Canadian Yukon, came in at the top of the world with only 3 microns. The top 70 cities in the world all recorded 10 or fewer microns. Of those, two are in Australia and all the rest are in Canada and the United States.
One of the clearest points from the WHO map is that Canada, the United States and Australia are uniformly clean, followed by Europe and trailed by the rest of the world.
The most polluted city in the United States was Bakersfield, California, ranked 808th in the world but reporting just 38 microns. Bakersfield was only half as polluted as Iran’s cleanest city—Shiraz, which ranked 963rd and reported 70 microns.
Of the 100 most polluted cities in the world, 24 are in India, 20 in China, 16 in much smaller Iran, seven in Turkey and six each in Pakistan and Saudi Arabia with the other 21 scattered across 15 countries.
Here are the 10 most polluted cities in the world (Iranian cities capitalized) with their rankings first and the PM10 measure in microns per cubic meter following their names:
1082 AHVAZ 372
1081 Ulan Bator 279
1080 SANANDAJ 254
1079 Ludhiana (India) 251
1079 Quetta 251
1077 KERMANSHAH 229
1076 Peshawar 219
1075 Gaborone (Africa) 216
1074 YASUJ 215
1073 Kanpur (India) 209
These are the only cities to report measurements greater than 200 microns. And Ahvaz was the only city in the world to report more than 300 microns. These cities are in a class by themselves when you consider that Bakersfield is listed three-fourths of the way down the list but has a pollution measure only 10 percent that of Ahvaz and only 18 percent that of Yasuj. The dirtiest cities on this list are really dirty.
Here are the other 14 cities in Iran where PM10 measurements were recorded.
1066 Urumiyeh 183
1065 Qom 176
1063 Khorramabad 168
1044 Ilam 129
1041 Bushehr 125
1041 Kerman 125
1029 Qazvin 112
1019 Esfahan 105
1013 Hamadan 103
1012 Arak 102
1001 Tehran 96
990 Mashhad 87
980 Tabriz 82
963 Shiraz 70
For the sake of comparison, the micron counts in some other major cities were 18 in Washington, 21 in New York, 23 in Tokyo, 25 in Los Angeles and 38 in Paris.
Los Angeles has only one-fourth the particulate matter of Tehran. This would not have been true a half-century ago when Tehran had few cars and Los Angeles was choking under smog largely caused by cars that pumped out pollutants. The US anti-pollution laws started in earnest in the early 1970s. Much of the public pressure for that effort came from Californians who felt they were being strangled by their air.
The major contributor to Tehran’s pollution a half-century ago was the large number of brick kilns south of the city. Those were moved away decades ago.
The WHO said that the average level of PM10 pollution for all these 1,082 cities is 71 microns. Thus, Iran had only one city that bested the average, Shiraz, but that was only by a solitary micron.
This is the first global tabulation of pollution levels ever published by the WHO. WHO said it was publishing the list to highlight the need to attack pollution. It said investments to lower pollution levels quickly pay off due to lower disease rates and, therefore, lower health care costs.
WHO recommends an upper level of 20 microns of PM10. None of the Iranian cities tabulated even came close to that, with Ahvaz at 19 times the recommended maximum.
The mayor of Whitehorse, Bev Buckway, was queried by The Associated Press about being the world’s least polluted city. “It’s absolutely wonderful,” she said. “A lot of people come up north and they smell the air and they say, ‘Oh, wow, amazing. The air smells so good.’ And we tend to take it for granted because we just have that all the time.”
