BY JOHN RICHARDSON

Portland Press Herald

It doesn't take modern science to tell you what stinks and what doesn't. Every nose knows that.

But a team of state odor police is hoping technology can finally help it set an enforceable standard for stink and, ultimately, freshen the air around some of Maine's smelliest solid-waste handlers.

"We feel we need to come up with some quantifiable way to measure odor," said Carla Hopkins, an environmental specialist with the Maine Department of Environmental Protection and a member of its odor team. "What we found is that it's really hard. ... We knew it was going to be tough going in."

The DEP team is testing modern smell-measuring equipment and developing a stink-rating system that, if successful, will become one of the country's most comprehensive odor control rules. The team will report on its progress to Maine lawmakers this week and hopes this spring to propose its solution to one of the oldest, and trickiest, environmental complaints.

"It's rather complicated," said Paula Clark, the DEP's director of the division of solid waste. Regulating bad smells is a recurring challenge for communities and states around the country. Maine, like many states, simply prohibits solid-waste facilities and others from creating nuisance odors.

"If, in our judgment, an odor occurred long enough, if it occurred frequently enough, if it was intense enough ... it would be deemed a nuisance," Clark said.

The DEP has issued fines and orders to eliminate nuisance odors in some such cases. More often, however, there is not enough evidence to take action. Smells fade, winds change and different noses do not always agree about how strong, or foul, an odor is.

"It's very difficult to administer because it is more of a qualitative type of thing," Clark said. "The big difference with what we are looking at is the technology that is available now concerning odor measurement, and trying to establish a quantitative odor standard -- something we can actually manage in the field."

Nothing beats a nose

There is still no technological substitute for the human nose, no scientific instrument that can reliably measure smell. But there are some gadgets that can help humans measure the intensity of stink from such sources as trash, manure or sewage.

The DEP regulators got training last year and began testing the technologies at several of Maine's smelliest dumps, composters and sludge spreaders, including the Bath landfill and Kay-Ben Farm in Gorham, a dairy farm that also composts solid wastes.

One system is known as an "n-butanol scale," which involved a series of numbered vials containing odors in a range of intensities. A regulator sniffs the vials to determine which one most closely matches the intensity of the odor from a nearby landfill or compost pile, for example.

The n-butanol scale is used by some states and communities to define exactly what is a nuisance odor. Portland officials, for example, use the n-butanol test in cases of chronic odor complaints and consider a score of three or higher to be too high for a residential neighborhood.

A second gadget is an olfactometer, or smell meter. The DEP is testing out a brand called the Nasal Ranger, which costs about $1,500.

In this case, the instrument is held to the regulator's nose and the offensive odor is drawn through. The user keeps sniffing while turning a dial that gradually diverts the odor through a carbon filter. When the sniffer can no longer smell the odor, the Nasal Ranger gives a dilution value that can be used to rate the stink.

The two systems produce intensity readings that are relatively objective and can be compared to an enforcement standard, said Carla Hopkins, one of the DEP environmental specialists leading the effort.

There is still a human element, although the DEP tried to account for that by selecting its study team by testing candidates' smell sensitivity, Hopkins said. Most of the team members -- all from DEP's solid waste division -- were average sniffers, while one was high on the sensitivity scale, she said.

The team plans to do more testing in the coming weeks, in part to determine how winter weather affects the readings.

It also plans to include qualitative standards, such as duration or odors and how pleasant or unpleasant the odor is, a factor known as "hedonic tone." In the end, the DEP hopes to incorporate all of the criteria into one comprehensive rule that would apply to solid-waste operations, the source of most complaints.

Rules proposal

The DEP hopes to propose formal rules in spring, and could implement them later this year.

Maine communities could still enforce their own stricter rules, but a clear statewide standard for what constitutes a nuisance odor would be helpful for cities such as Portland, said Alex Jaegerman, the city's planning director. Portland, for example, deals with odors from food processing businesses, which wouldn't be covered by the new state solid waste odor standard.

And, if the effort means stronger enforcement, a new standard could bring relief to communities such as Biddeford and Saco. Residents and business owners there have been complaining for years about the smell of trash from the Maine Energy waste incinerator.

"I don't need any fancy gadgets to tell me it smells," said Mark Johnston, a former Saco mayor and a landlord and business owner.

Johnston has sued Maine Energy to stop releasing odors that he says are holding back economic development in the community and have driven away his own business and residential tenants. While anxious to see the new proposed rules from DEP, Johnston insists the state doesn't have to wait for a scientific test to crack down on the stink.

"It's like the Supreme Court ruling on pornography -- when you've seen it, you know you've seen it," he said. "When a major portion of your population starts to complain about odor, then it's a nuisance."

The old-fashioned smell test can justify a state fine, but usually isn't enough, in part because it's so subjective, said Brian Phinney, Biddeford's environmental code officer.

"It is certainly a tool they can use. It's just not a definitive standard that can be applied equally around the state," he said.

Biddeford police or code officials respond to about 60 complaints a year of odor from Maine Energy, he said. Each time, a city official and a representative of the plant respond and rate the odor using the n-butanol scale to determine if it is above or below the level of an official nuisance.

The city has issued one violation notice so far, although that one is under dispute.

Phinney also is experimenting with the Nasal Ranger, and said it might be helpful in some, but not all, cases. It may not work fast enough if an odor comes and goes, for example.

A clear, standardized state rule would be welcomed by Maine Energy, too, said Ken Robbins, the facility's manager. "Anytime you're held accountable to a standard and it's a measurable standard, that's a good thing," he said.

But, in the end, even using an olfactometer is still not totally objective, he said. "It's not the exact science that we all want, because a human nose is still stuck at the other end of it."