ENVIRONMENT-BRAZIL: Sao Paulo Smog Starting to Clear

By Mario Osava Reprint | | Print |

Mario Osava

RIO DE JANEIRO, Sep 10 1999 (IPS) - Air quality in Sao Paulo – Brazil’s biggest city and one of the largest in Latin America – has improved in recent years, but not enough, according to experts.

The greater Sao Paulo, population 17 million, remains one of the world’s most polluted cities.

The average daily level of carbon monoxide in the air, which peaked at 27.8 parts per million (PPM) in 1994, dropped to 14.3 PPM last year and to a current range of 10 to 12, said Jesuino Romano with the governmental Company of Environmental Clean-up Technology.

But that is still far from the maximum acceptable limit of nine PPM, said the head of the Air Quality Division of the government agency, which is the top environmental authority in the state of Sao Paulo.

The number of particles inhaled has also been reduced by one- third in the past few years, but remains 10 percent above the acceptable level of 50 micrograms per cubic metre.

The improvement can largely be chalked up to a Programme to Control Vehicular Air Pollution, which forced the automobile industry to drastically curb the toxicity of vehicle exhaust fumes.

The pollution level of nationally manufactured vehicles, which until 1980 released 54 grams of carbon monoxide per kilometre driven, was cut to one-quarter of that by 1990, and to 0.79 grams per kilometre last year.

Thanks to that major change, the air in Sao Paulo is cleaner today, even though the number of vehicles circulating in the metropolitan region climbed from 4.3 million in 1994 to 5.4 million in 1998, said Romano.

Other elements contributing to the reduction in pollution were improved quality of fuel – which now leaves less toxic residues – pressure to reduce the clouds of black smoke released by buses and trucks, experiments in replacing gasoline and diesel fuel with natural gas, and decreased industrial pollution, he added.

Many companies have pulled out of the crowded metropolis to set up shop in smaller cities in the state of Sao Paulo or other states, where they pay lower wages. Those that stayed have been forced to take measures to control and treat their waste products.

The phenomenon of the flight of industry towards the interior, which intensified this decade, was key to the health of the residents of the somewhat ironically named Saúde (Health) neighbourhood of Sao Paulo.

Emissions released by the Aliperti steelworks operating in the area turned houses grey and caused illnesses, said Celia Neri de Camargo, a hairdresser whose young daughter suffered frequent episodes of bronchitis after they moved to the neighbourhood 23 years ago.

But according to De Camargo, the air has improved greatly since the company transferred its central plant to the interior and adopted pollution control measures in the factory still operating in the neighbourhood.

Local authorities and residents began to show serious concern about pollution levels in Sao Paulo in the mid-1970s, when the air became unbreathable at times in winter, when temperature inversion trapped the pall of fumes spewed out by the city’s vehicles and factories.

Systematic monitoring of air quality and pollution control measures applied to vehicles and local companies have gradually been adopted.

Four years ago, in order to deal with the mushrooming of the number of vehicles driven in the city, a system was implemented by which 20 percent of cars were removed from circulation on a rotating basis Monday through Friday, during the winter months.

This year, the state government decided to suspend the rotating restriction on driving, which was maintained as an emergency measure, to be applied when weather conditions aggravate pollution levels. That has not been necessary so far, however.

The reduction of pollution levels is a slower process today, said Romano. Technological advances leading to reduced levels of contamination by vehicles, industries and fuel can only go so far, and each new advance tends to bring less outstanding results, he pointed out.

The possibilities for further reducing air pollution levels now lie mainly in improving the mass transit system and thus cutting the number of cars on the streets, Romano added.

Rotating bans on driving have not only served to reduce smog, but have also significantly improved the city’s congested traffic, while fuelling a debate on the need for an improved public transport system.