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public health

Fewer deaths from the air

An international group shows the benefits that the drop atmospheric pollution rate brings to public health in four large metropolises

The mere reduction by 10% in two pollutants – particle material (black smoke) and ozone -, through alternative technologies already available to the burning of fossil fuels, would be sufficient to avoid, in four large American cities, 64,000 pre-mature deaths, 65,000 cases of chronic bronchitis and 37 million lost working days over the next twenty years – which would bring in huge costs reduction and benefits to the economy in general. The alert this time is not from environmentalists. It is the epidemiologists of the United States, Chile, Mexico and Brazil who are calling attention towards the necessity of containing global warming and its disastrous consequences, provoked by the emission of greenhouse effect gases.

On studying the effects of pollution on the health of the populations of New York, Mexico City, Santiago in Chile and São Paulo, the researchers demonstrated that a reduction in the emission of greenhouse gases as it was predicted in the Kyoto Protocol, would bring immediate benefits to public health. Their objective was to bring up arguments that would help to settle the current impasse in the discussions surrounding the Kyoto Protocol. To do so, they developed quantitative estimates based on published scientific papers The working group brought together Luis Cifuentes from the Catholic Pontificate University of Chile, in Santiago; Victor H. Borja-Aburto from the Health Department of the City of Mexico; George Thurston from New York University School of Medicine, New York; Devra Le Davis from Carnegie Mellon University in Pittsburgh, United States; and Nelson da Cruz Gouveia from the Department of Preventative Medicine of the Medical School of the University of São Paulo (FM-USP).

To comply with the Kyoto goal, the signing countries have the period from 2008-2012 to reduce by at least 5% their pollutant emissions in relation to the volume emitted in 1990. This could imply alterations in their economic growth rates in terms of fuel burning . Nevertheless, practically all of the countries signed the agreement, with the exception of the United States, which although isolated in its position, could jeopardize the objectives of the international agreement. “The United States ontheir own correspond to close to one quarter of the total emissions of the whole planet” reminds Gouveia.

Released in an article which the group published in the magazine Science , on the 7th August issue, the research shows that, if the United States were to reduce its emissions in the agreed proportions of the Protocol, they could almost immediately avoid 18,700 deaths and 3 million lost working days per year.Though the studies and projections – for the period 2001-2020 – base themselves only on the data from the four metropolises, the debate was enlarged with data from other countries and estimates by the World Health Organization (WHO), which has forecast 8 million deaths linked to pollution up until the year 2020.

In the end – and going against the theory of those who pretend to downplay the effects of the reduction of emissions as slow to appear, extremely expensive, and of little effect – they state categorically that the gradual adoption of production technology of clean energy will bring immediate benefits to close to 3 billion inhabitants of urban centers. “If the countries were to adopt today the available methods of combating pollution, such as improving public transport, the use of cleaner fuels and to adopt technologies to reduce vehicle emission, they would immediately begin to save lives and to prevent a large number of limiting illnesses that have serious socio-economic implications.”

Guilty vehicles
The main atmospheric pollutants are particle material (composed of dust and inhaleable particles resulting from the burning of fuel) carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2) and ozone (O3), which in the high atmosphere protects the earth from ultraviolet rays, but in the lower atmosphere is extremely harmful to man, and to animals and plants.In São Paulo, where 30% of the national fleet circulates, as in the other metropolises, the single most item responsible for pollution is the motor car vehicle. “They spew out into the city 98% of the carbon monoxide, close to 60% of the particle material and something in the range of 50% to 90% of the other pollutants”, reveals Gouveia.

The quality of the São Paulo air was worse in the past. In the decade of the 80’s, the average level of particulate material ran to around 75 mg/m3 (milligrams per cubic meter) well above the 50 mg/m3 taken as the acceptable limit by the WHO. With the introduction of alcohol fueled vehicles, less polluting, and the addition of anhydrous alcohol to the petroleum as an anti-knock, in the place of the toxic tetra-ethyl lead, the annual level of particulate material fell – oscillating between 50 and 60 mg/m3 -, in spite of the increase in the vehicle fleet.

To create a further improvement there was the Federal Resolution of 1986 that created the Program of Vehicle Air Pollution Control (Proconve), imposing limits more and more severe on emission of pollutants by new vehicles. Today, according to the Company of Technology of Environmental Sanitation (Cetesb), cars pollute 90% less than in the 80’s. Even so, São Paulo is one of the most polluted metropolises: a survey from the Royal College of London places it in fifth place in a list headed by Cairo (Egypt), in second place Shanghai (China), then Mexico City and Karachi (Pakistan). In a better situation is New York in 11th place, and London in 12th, probably due to the fine infra-structure of public transport – above all the underground.

Unhelpful prohibition
From 1996 until 1998, and under penalty of a fine, the São Paulo driver was prohibited by the Federal government from using his car one day per week during the winter, according to the final number of his car’s number plate. While the municipal prohibition of circulation of vehicles attempted to reduce traffic congestion, the state equivalent intended to lower pollution. “Even by removing from the streets each day 20% of the light vehicle fleet, the measure didn’t achieve the expected effect”, says Gouveia. He compared the pollution rates of August during the three years of the reduced use with the three previous years. The pollution had in fact gone down by close to 17%, but not necessarily due to the lowered circulation of vehicles. According to this study, the reduction resulted, in a large part, from a grouping of environmental factors – temperature, air humidity, rainfall and winds that contributed to the dispersal of the pollutants.

For Gouveia, the reduced circulation was a failure as it left out the major polluters, close to 400,000 diesel vehicles that spew out 12,400 tons of particulate material per year in the metropolitan region. The experiment also did not do very well in Mexico City or in Santiago in Chile. “The longer the time period of the reduced circulation, the less effect it has”, he says. However, he does not discard the restriction in a time of acute crisis, as it has occurred in Paris and other European cities. “Even then, as an isolated item, it brings few benefits.”

Children and the elderly
Gouveia concluded a project in which he evaluated the effects on the age groups most affected – children and the elderly – and the results of the state reduction of vehicle circulation, comparing the evolution of the rates of the main pollutants with hospital internments of children up to 5 years of age and of the elderly older than 64 years of age between 1996 and 1998. The cross checking of the measurements from the twelve air pollution monitoring stations of Cetesb with the registrations of hospital internments in the Unified Heath System (The Brazilian public health system SUS) showed, for example, that the greatest rates of internments and of pollution coincided with the winter months. Low temperatures favored the increase in the acute picture and deaths from respiratory diseases, which the pollution simply aggravated.

There was an increase in the internments of the elderly for circulation illnesses related to the high levels of carbon monoxide, which lowers the oxygen in the blood and can be fatal in a closed environment. In children and the elderly, the internments for respiratory illnesses were associated with carbon monoxide, inhalant particles and sulfur dioxide. “In general, during the most polluted days, the number of internments for respiratory illnesses rose by nearly 100% and the mortality generally had an increase of between 4% and 6%. Between the peaks of pollution and internment, there could be a difference in phase of up to three days, “perhaps the time necessary for the pollution to exercise its injurious effect”.

Another conclusion: the elderly are more affected. Except for the inhalant particles, the pollutants had an effect twice as high on the elderly in internments for respiratory illnesses than on children. As these illnesses are among those that kill the most in the country – the cardiovascular illnesses are those most deadly to the elderly, respiratory illnesses come in third place for them and in first place for children -, the data can help in the formulation of public health policies.

Risk of regression
Good use can be made of experiences abroad. “However, isolated measures are not going to bring on the desired effect”, alerts Gouveia. “São Paulo needs a plan of integrated measures, capable of attacking the problem on various fronts. As well as reducing vehicle emission, it is necessary to implement an annual inspection of all of the vehicle fleet and to invest in public transport.”The danger lies in the growth of the vehicle fleet. Over the last 20 years, that of São Paulo grew by 215%, close to 12 times more than the population increase of 18%. On average, there are 170,000 new vehicles per year.

Also, it is estimated that the levels of particulate material increases by 20 mg/m3 for each 100,000 new vehicles – and the effect of the reduction of the emissions by new vehicles ends up losing its effect. Gouveia gives value to the search for alternative technologies for the substitution of fossil fuels, such as the fuel cell. “They are long term solutions”, he says. “Until then we cannot remain with our arms cross while so many people fall ill and die.”

Limits for the polluting fleet

Created in 1986 and beginning from 1998, Proconve established emission limits to be respected by all new vehicles produced in the country or imported. Inspired by similar situations in developed countries such as the United States and Japan, the program established differential stages for the reduction by light vehicle emissions (both petroleum and alcohol) and heavy duty vehicles (diesel), as well as urban buses.

For example, the light vehicles had to pass from the maximum emission of 24 g/km (grams per kilometer driven) of carbon monoxide (CO) in 1989 to 12 g/km in 1992 and to 2 g/km in 1997. Also limits for the emission of carbon monoxide at low speed and for the emissions of hydrocarbons or unburned fuel (HC) and of nitrogen oxides (NOx) were fixed. The alcohol cars also were given fixed limits for the reduction of the levels of pollutants gradually obtained through the adoption of technological measures such as the generalized use of exhaust catalysts and of electronic fuel injection systems, improvement in fuels and lubricants and of the performance of the motors themselves.

Through the measures adopted by Proconve, the emission of pollutants in new motorized vehicles throughout the country reached 90% at the end of the decade of the 90s in relation to the situation at the beginning of the program.

The Project
Air pollution, the Staggered Circulation of Vehicles and Effects on the Morbidity of the Elderly in the Municipality of São Paulo (nº 98/11171-9); Modality Regular line of research assistance; Coordenator Nelson da Cruz Gouveia – Medical Faculty of USP; Investment R$ 8,850.00