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– The Environmental Protection Agency plans to change the way it calculates the health risks of air pollution, a shift that would make it easier to roll back a key climate change rule because it would result in far fewer predicted deaths from pollution, according to five people with knowledge of the agency's plans.

The EPA had originally forecast that eliminating the Obama-era rule, the Clean Power Plan, and replacing it with a new measure would have resulted in an additional 1,400 premature deaths per year. The new analytical model would significantly reduce that number and would most likely be used by the Trump administration to defend further rollbacks of air pollution rules if it is formally adopted.

The proposed shift is the latest example of the Trump administration downgrading the estimates of environmental harm from pollution in regulations. In this case, the proposed methodology would assume there is little or no health benefit to making the air any cleaner than what the law requires. Many experts said that approach was not scientifically sound and that, in the real world, there are no safe levels of the fine particulate pollution associated with the burning of fossil fuels.

Fine particulate matter — the tiny, deadly particles that can penetrate deep into the lungs and enter the bloodstream — is linked to heart attacks, strokes and respiratory disease.

Asked Monday whether the new method would be included in the agency's final analysis of the rule, William Wehrum, the EPA air quality chief, said only that the final version would include several analytical approaches in an effort to be transparent. He said the agency had made no formal change to its methodology.

The EPA, when making major regulatory changes, is normally expected to demonstrate that society will see more benefits than costs from the change. Experts said that, while benefits would appear on paper in this case, the change actually disregards potential dangers to public health.

"Particulate matter is extremely harmful, and it leads to a large number of premature deaths," said Richard Revesz, an expert in environmental law at New York University. He called the expected change a "monumental departure" from the approach both Republican and Democratic EPA leaders have used over the past several decades and predicted that it would lay the groundwork for weakening more environmental regulations. "It could be an enormously significant impact," he said.

The Obama administration had sought to reduce planet-warming greenhouse gas emissions under the Clean Power Plan by pushing utilities to switch away from coal and instead use natural gas or renewable energy to generate electricity. The Obama plan would also have what is known as a co-benefit: Levels of fine particulate matter would fall.

The Trump administration has moved to repeal the Obama-era plan and replace it with the ACE rule, which would slightly improve the efficiency of coal plants. It would also allow older coal plants to remain in operation longer and result in an increase of particulate matter.

Wehrum acknowledged that the administration was considering a handful of analyses that would reduce the prediction of 1,400 premature deaths as a result of the measure.

He called the attention given to that initial forecast "unfortunate" and said the agency had included the figure to show the varied results that can be achieved based on different assumptions.