The Environmental Protection Agency (EPA) rolled out plans Friday to toughen standards for fine particulate matter, or soot, which is dangerous microscopic pollution emitted by factories, power plants, diesel vehicles and other sources.

The proposal, which the agency is issuing under a court-ordered deadline, would pare the current annual exposure standard of 15 micrograms per cubic meter down to between 12 and 13.

{mosads}EPA’s plan is certain to fuel election-year political fights over the Obama administration’s regulatory agenda. Lobbyists for oil companies and other industries have pressed the administration to maintain the current standards, warning that tougher rules will take an economic toll.

National Association of Manufacturers CEO Jay Timmons said the new soot standards will create difficult requirements for existing factories, and create hurdles to permitting new plants.

“The scope and damaging impact the EPA’s new standard will have on manufacturers across the country, both large and small, is troubling,” he said in a statement.

But EPA said that separate Clean Air Act rules finalized recently will go a long way toward ensuring the new soot standards are met.

“Ninety-nine percent of U.S. counties are projected to meet the proposed standards without undertaking any further actions to reduce emissions,” EPA said in announcing the proposal Friday.

The George W. Bush administration in 2006 maintained the annual fine particulate standard that was set in 1997, but did toughen the 24-hour exposure standard.

Fine particulate pollution is dangerous because it can reach deep into the lungs and enter the bloodstream. The soot is linked to a range of respiratory and cardiovascular problems such as asthma, bronchitis and irregular heartbeat, according to EPA.

The agency plans to finalize the rules by mid-December.

The American Lung Association, which along with other environmentalists and 11 states had sued EPA to force revised soot rules, applauded the decision to reduce the standard.

The group also for an even greater tightening, however, down to 11 micrograms per cubic meter.

“The American Lung Association is pleased that EPA has proposed a much tighter annual particle pollution standard that will prevent thousands of premature deaths and tens of thousands of asthma attacks each year. We will examine the proposal and work through the public comment process to urge the most protective standard,” said Paul Billings, the American Lung Association’s vice president for national policy and advocacy, in a statement.

League of Conservation Voters President Gene Karpinski called the rules “yet another welcome step toward protecting our families from the harmful effects of deadly air pollution.”

But Jeff Holmstead, a partner with the firm Bracewell & Giuliani, warned of the economic effect of the proposed changes. Holmstead was EPA’s top air regulator under Bush.

“It may not sound like much — lowering the standard from 15 to 13 — but it will mean a lot more regulations in many parts of the country. This won’t be good news for places trying to attract new manufacturing jobs,” he said.

The EPA proposal will likely draw the ire of Capitol Hill Republicans, who say EPA has already been pursuing an overzealous agenda.

Republicans and some conservative Democrats have been seeking to roll back recent air toxics standards for coal-fired power plants and separate rules targeting smog-forming pollutants from power plants, arguing the measures are too aggressive.

Top Republicans on the House Energy and Commerce Committee this month pressed EPA Administrator Lisa Jackson to maintain the current soot standard.

“Stringent standards that seek to control a ubiquitous and naturally occurring pollutant will likely be costly and have significant regulatory and other implications,” they wrote to Jackson on June 6.

But EPA, in touting the rules, said the public health gains from the tighter soot standards will yield economic benefits that far outstrip the costs.

“Depending on the final level of the standard, estimated benefits will range from $88 million a year, with estimated costs of implementation as low as $2.9 million, to $5.9 billion in annual benefits with a cost of $69 million — a return ranging from $30 to $86 for every dollar invested in pollution control,” the agency said Friday.

—This post was updated at 11:08 a.m.