N.E. faces increase in smog warnings

New rules spotlight harmful exposure

The sweltering temperatures have hardly begun, but unhealthy, smoggy air has permeated parts of New England 18 days already, and many more are in the forecast.

It's not that the air suddenly got dirtier. Rather, the federal government in March lowered the threshold for declaring the air unhealthy, based on research showing that smog is far more harmful at lower concentrations than previously believed.

As a result, environmental officials say there will probably be substantially more days in the future when residents are warned to minimize physical activity outdoors because of dirty air. Last year there were 26 such days. If the new rules were in effect then, there would have been about twice as many.

"The air is getting cleaner," said Paul Miller, deputy director of the Northeast States for Coordinated Air Use Management, a nonprofit association of state air quality agencies. But Massachusetts remains out of compliance with clean-air rules, even using the old smog standard.

Smog can cause coughing, aggravate asthma, inflame the lining of lungs, and make those with preexisting respiratory problems more susceptible to serious breathing troubles. A recent report by the National Research Council, a scientific group that advises the federal government, concluded that even short-term exposure of less than 24 hours can shorten lives. Children are particularly vulnerable, as are adults who exercise outdoors.

Tighter pollution controls on power plants and vehicle emissions testing have sharply reduced smog-forming emissions in the last 25 years. New England states must now come up with ways to meet the new standards.

"Our experience doing this us gives us great optimism we can achieve even" cleaner air, Miller said.

Most people are familiar with smog, the ground-level ozone haze for which Los Angeles is infamous. It forms when vehicle and industrial emissions react with sunlight. In New England, smog is largely a summertime problem, usually when temperatures are above 85 degrees and winds blow from the southwest. (Air is expected to be healthy today throughout most of New England.)

It's not just a city concern. Smog occurs throughout Massachusetts because a significant portion, probably more than half, of our smog-making pollutants originate in other regions and are carried here by the winds. Cape Cod, for example, tends to get New York's air pollution.

"People say let's escape to Cape Cod, but those areas may also have air quality problems," said Anne Arnold, manager of air quality planning for the US Environmental Protection Agency's New England regional office.

The new federal standards, which are based on the average concentrations of ozone over an eight-hour period, were lowered from 85 parts per billion to 75. Many states, including Massachusetts, Maine, New Hampshire, Connecticut, and Rhode Island, as well as environmental groups, sued the Bush administration in May, saying that the new limit should be even lower because the EPA's own scientific advisory panel recommended that the standard be set no higher than 70 parts per billion. EPA chief Stephen Johnson has defended the agency's decision, saying the smog limits were the most protective in US history.

Under a complicated formula, Massachusetts is considered in violation of EPA's smog standards because it has had too many days of unhealthy air over a period of several years. Rhode Island and Connecticut are also out of compliance.

"We know we are not meeting the new standard . . . [because] we are not meeting the old standard," said Barbara Kwetz, director of air and waste planning for the state Department of Environmental Protection.

Massachusetts has until 2013 to decide how it will come into compliance.

It is a difficult goal. The state has no control over emissions that winds carry here from coal plants in the Midwest and elsewhere. And in some cases, the state is barred by the federal government from setting tougher emission rules for certain industries and vehicles than those that exist.

Still, the state recently passed new rules for consumer products and paints, which can release compounds that contribute to smog.

Regulators are also writing rules to lower emissions related to the manufacture and use of asphalt, sealants, and solvents.

"Of course we are not guilt-free and we are working on [our smog pollutants] that contribute downwind to Maine," Kwetz said. "But there is not one silver bullet."

This week, the EPA released a draft report that said manmade climate change would probably cause more smog in the Northeast, but that analysis did not take into account improvements in air quality over time.

A separate EPA computer model shows that Massachusetts would be in compliance with national air quality standards by 2020 if air quality improvements continued at the current pace.

"We've made progress," said Miller. "We've demonstrated we know how to get reductions."

Beth Daley can be reached at bdaley@globe.com.