T proponents say expansion is a matter of life or death

Advocates for expanded transit service in urban neighborhoods are turning to a new theme in their push for projects: Death.

In Somerville, where residents are clamoring for an extension of the Green Line, one group published a chart showing disproportionate death rates from air pollution-related disease in that city.

More people using electric trolleys means fewer people driving cars on Interstate 93 or taking diesel buses or commuter trains, said Wig Zamore, a member of Somerville Transit Equity Partnership, who assembled the data from the state Department of Public Health and passed it out at a recent meeting with state and MBTA officials.

''This is unquestioned in the scientific community today: There's a linear relationship between air pollution and mortality," said Zamore, who said neighboring communities such as Chelsea, Malden, and Revere can make a similar argument. ''If you're putting people in the greatest concentrations of population without putting in the transportation to clean up the air, you are basically signing a death warrant."

The language is unusually stark for activists trying to get an extension of a transit line. But the stakes have grown higher: Officials say that after three decades and billions in expansions, the T will expand no further.

Tonight in Malden, the Massachusetts Bay Transportation Authority goes on the road for the first of eight public hearings on a five-year construction plan that includes hardly any major system expansion. Beyond completing the Silver Line and restoring the Greenbush commuter rail, the T can't afford to add to the system, said General Manager Michael Mulhern. He said he wants to avoid being overextended like other large transit systems, resulting in fare hikes and service cuts.

The Romney administration has also balked at providing funding for any major expansion of the T, despite a 1990 agreement linking system expansion to the construction of the Big Dig. State officials have scheduled a public hearing for Dec. 14 at the State House to discuss substitutions for the projects listed in that pact, which include the Green Line extension, trolley service for Jamaica Plain, and a Red-Blue line connector in Boston, among others.

Philip Hailer -- spokesman for the Office of Commonwealth Development, which oversees major transportation planning -- said that the state takes any legitimate claims about air pollution and public health ''very seriously," but that the state wants to pick the transportation projects that deliver the most air quality benefit.

Zamore was undeterred. At a recent meeting attended by Mulhern and Robert Golledge, the commissioner of the state Department of Environmental Protection, Zamore placed a copy of the chart showing air pollution-related deaths on every seat.

The state is required to meet clean air goals under federal law, Zamore pointed out, and if the state fails to build transit projects that help meet those goals, the federal government could cut off all transportation funding. That is a scenario faced in recent years in Atlanta, Baltimore, and San Francisco.

Several studies have suggested a connection between air pollution and premature death, including one done by the Harvard School of Public Health, and most believe ''there is a direct link," said David Conroy, manager of air quality planning for the Environmental Protection Agency.

When setting air quality standards for power plants or diesel engine emissions, the EPA will do an analysis showing how many fewer people will die as a result of cleaner air. But virtually all such analysis is done on a regional basis, Conroy said.

''We don't predict by community," he said.

Mulhern said while expanding public transit helps clean the air, it might be a stretch to say it's a matter of life or death if one community does not get a transit line. ''It's an interesting way to promote transit investment," he said.

Mulhern said that the T's recently released Capital Investment Program report was more than 80 percent for maintaining and enhancing the existing network. He said he will not take on any new projects if he cannot maintain the current system.

The T is wrapping up two major projects. One is the second phase of the Silver Line -- the busway from South Station to the South Boston Waterfront, with eventual service to Logan Airport -- set to open Dec. 17. The other is the restoration of the Greenbush line to the South Shore, a $479 million project facing lawsuits and environmental problems and already projected to miss the initial 2006 completion date.

Anthony Flint can be reached at flint@globe.com