The city’s 35,000 diesel-powered vehicles and 6,000 private school buses that contract with the city would be required to be retrofitted with pollution controls under sweeping legislation introduced yesterday aimed at reducing asthma rates.

The legislative package, comprising five bills, calls for city-owned vehicles -except emergency vehicles – to undergo a $1,000 to $16,000 overhaul and use ultra-low-sulfur diesel fuel by the end of next year.

It also would ban sightseeing buses and independent, city-contracted garbage trucks that do not operate on ultra-low-sulfur diesel.

Federal regulators have said that all diesel fuel sold in America must be ultra-low-sulfur by 2006 and that all new diesel vehicles must have advanced emissions controls by 2007.

City Council Speaker Gifford Miller said the legislation would jump-start the city’s efforts to comply with the federal mandate and reduce pollution in the meantime.

The giant diesel engines used in buses and trucks produce a disproportion ate share of air pollution, particularly soot – a major contributor to asthma – and sulfur. Studies have shown that pollution levels inside some buses are often higher than outside.

Speaking at City Hall, Mr. Miller showcased a white linen cloth stained with black soot that he said was held over the exhaust pipe of a diesel-operated bus. Another, nearly pristine, white linen cloth he said was held over the exhaust pipe of an ultra-low-sulfur diesel bus.

“This is the right thing to do,” Mr. Miller said. “Too many children are suffering, and the sad thing is it’s needless.”

According to the city Health Department, roughly 700,000 adults and 300,00 children living in New York City suffer from asthma. A recent study by the Columbia Center for Children’s Environmental Health found that one in four children in the South Bronx and Harlem is afflicted with the respiratory ailment.

Emissions can be reduced by more than 90% with pollution-control devices in conjunction with ultra-low-sulfur diesel.

The retrofitting could cost the city from $40,000 on the conservative end to $500 million. But officials, citing Health Department data, said the total cost of asthma hospitalizations in 2000 was $242,454,056.

One of the bills is an expansion of legislation passed by the council in 1990, which mandated that city purchases of vehicles under 8,500 pounds be alternative-fuel vehicles. The new benchmark would be 14,000 pounds.

The legislation has the support of the American Lung Association, the American Cancer Society, and several environmental groups.

“The fight against asthma rates rests in large part on our ability to reduce environmental triggers that can cause asthma exacerbations,” said Dr. Neil Schluger, president-elect of the American Lung Association.

Last year, an organization representing New York State school bus operators reportedly offered to retrofit about 1,000 school buses in New York City at no cost to the owners, but the operators were reluctant to take part.

They said they feared the changes could harm their buses, although the Metropolitan Transportation Authority’s buses and other big fleets have undergone similar changes.

Phone calls to three companies that operate school buses in the city were not returned yesterday.