Cars running on sugarcane ethanol can produce as many harmful pollutants as those using ordinary petrol (gasoline), according a study published by Brazil's environment ministry.

But the report on the emissions of the cars on Brazil's roads does not count carbon dioxide emissions.

"We want to make sure that customers are aware of pollutant emissions" when they buy a car, Environment Minister Carlos Minc said Tuesday on delivering the report.

The study ranked emissions based of a scale of "green grades" that measured three pollutant gases that do not produce climate change but do affect the health of a country's population: carbon monoxide, hydrocarbons and nitrogen oxide.

The green grade scale, ranging from 0-10, does not count carbon emissions, which are the main driver of global warming, because emissions from burning ethanol are offset by the carbon dioxide that sugar cane absorbs as it grows, the study said.

The research also examined 250 so-called "flex-fuel" cars, which use both ethanol and petrol and constitute about 85 percent of all cars on the road in Brazil.

Among those receiving the lowest scores, eight were cars running on ethanol, including several with "flex" engines, the study said, though all of the models examined met Brazil's standards for maximum emissions levels in 2008.

Environmental group Greenpeace welcomed the report, but an official with the group's climate change campaign in Brazil, Joao Talochhi, told Estado de Sao Paulo newspaper that "when it comes to public health, the Brazilian government should invest in non-polluting vehicle technology."