According to WHO (World Health Organization) Buenos Aires is among the capitals of South America with the best quality of air. Out of the results the WHO did, BA seems to be the number three South American capital in the list. Only Montevideo (Uruguay) and San Jose (Costa Rica) have cleaner air.Buenos Aires is listed before México City (Mexico), Santiago (Chile) , Lima (Peru) , Bogota (Colombia) , Quito (Ecuador) and Sao Paulo (Brazil).
The WHO has a database with all information about the air quality in 1,600 cities worldwide. A lot of people have second thoughts about the good score of Buenos Aires because tested the air in only three places in the huge metropolis.
Scientists of the WHO look for suspended particles (or PM10) in the air. According to their study, Buenos Aires had 30 mg/m3 of suspended particles. The WHO’s own rules say that the level of PM10 might not be higher than 20 mg/m3, but the local authorities and the European authorities say it might be respectively 50 mg and 40 mg/m3. If you compare the score of the Argentine capital with 30 mg/m3 is way better then the Mexican capital with an air quality of 93mg/m3.