Wayne Poling jabbed one of his thick fingers in the direction of a huge industrial washing machine, a heaving, clanking beast that drones along with the sound of the pop music blaring from the overhead speakers.

"It seems like such a waste," he said above the din, "but I guess I'm going to have to get rid of it."

Poling, a stocky, round-faced man of 45, is standing in the back shop of his small Northern Virginia business, the Vienna One-Hour Cleaners, on Vienna's main drag 15 miles west of Washington. Just past the front counter, the big building givesway to the quarter-acre-sized back shop, a cluttered factory where a mountain of plaids, stripes and solids -- 12,000 pounds of laundry a week -- gets sorted, cleaned, pressed and bagged in plastic.

Business has been good lately for Poling. He has a second location and draws customers from as far away as the District. But a note of doubt is unmistakeable in his soft West Virginia accent. The problem is the washing and drying equipment on which his business is dependent. Like thousands of other dry cleaners, Poling's equipment uses a solvent called perchloroethylene instead of water to clean the mountain of clothes. "Perc," a suspected carcinogen, is one of 191 such compounds whose emissions would be restricted under revisions to the Clean Air Act, the landmark environmental bill whose passage in Congress appears imminent.

Even in this little corner of suburbia, cleaning the air carries a price. Poling is concerned that new regulations will force him to replace the aging cleaning equipment grumbling away in a corner of the back shop. Machines that use a newer technology are better at controlling the perc that escapes into the atmosphere, where it could then be breathed by workers in the back shop. But the new machines are expensive and slower than the existing ones -- in Poling's case, new equipment would cost him about $100,000. The bottom line, according to Poling: Customers should expect higher prices and an end to one-hour service.

"We all want clean air," Poling said, "but the question is, at what price? This is going to take a considerable investment. And most of the people in this business are like me, mom-and-pop operators."

For years, government efforts to clean the air have focused on the largest sources of pollution -- automobiles, coal-burning utilities, oil refineries, chemical plants. But under the far-reaching provisions of the Clean Air Act, thousands of small businesses that emit low levels of pollution-causing chemicals -- from auto-repair shops to bakeries to the corner dry cleaner -- may have to change the way they do business, according to both business advocates and environmentalists. In some cases, new equipment or new production processes may be needed; in others, it could mean a switch to different chemicals.

These changes may spur hardship and higher prices, but environmentalists argue that it's about time small businesses like Poling's begin bearing a greater share of the burden for cleaner air. After automobiles and big industries, small businesses are among the leading sources of toxic emissions, accounting for roughly 25 percent of the total, according to a study quoted by Daniel Weiss, the Sierra Club's director of environmental quality.

"Our belief is that the cost of the cleanup is far smaller than the damage done by not cleaning up," Weiss said. "How do you put a price on a pair of lungs?"

In fact, neither environmentalists nor business advocates know for sure how much the changes to the Clean Air Act will cost small businesses -- or how much the environment will benefit. The final emissions guidelines that will effect small operators won't be written by the Environmental Protection Agency until after the bill becomes law. The impact could be cushioned by provisions in the House and Senate versions that instruct regulators to weigh the financial impact on small businesses when writing the new standards.

Implicit in those instructions is the expectation that complying with new environmental standards exacts a relatively higher cost on a small business than a large one. Unlike major industrial polluters, which have been forced to invest in pollution control for years, small businesses have largely avoided such pressures by the federal government, said Teresa Pugh, the National Association of Manufacturers's environmental lobbyist. Catching up will be costly, she said.

Large businesses have an advantage because their size allows them to distribute the increased costs of pollution control over a number of product lines, said Pugh. "Small-business people," Pugh argued, "are really going to be jolted by this."

To be sure he can meet higher standards, Poling has already contacted his banker about financing new dry cleaning equipment, even though he believes his old machine "probably could keep chugging for years."

The good news, he said, was that the bank agreed to finance new equipment without exhausting his line of credit. The bad news: The bank will lend him only 75 percent of the cost, which means Poling will need to come up with $25,000 on his own. That's a tough nut for Poling, who is still paying back the debt he took on to buy the Vienna shop and another in nearby Oakton two years ago, the hard-won result of the 14 years he spent as an employee in the Vienna store. Although the customers keep coming, Poling figures the heavy debt he took on to buy the business means he won't turn a profit until 1993.

Poling has already outfitted the drying machine in his Vienna store with a vapor absorber, a $6,000 charcoal filter that captures and permits recycling of much of the escaping perc fumes. For added protection, Poling's laundryman, Sambo Phorn, wears a respirator mask and latex gloves when transferring a load from washer to dryer. Ceiling vents keep the air circulating. The unanswered question is whether the EPA's final rules will consider these steps adequate.

Proud of his environmental record, Poling challenged a recent visitor to the back shop to detect the smell of perc in the air. The visitor said he smelled a faint chemical odor, but Poling quickly pointed to a table full of bottled spotting agents, suggesting that they were the source of the faint odor.

"I've worked in this shop for the past 16 years," Poling said. "I've got 44 employees. My children are in here all the time. Even my baby, she's 7 years old, she's running around here with her friends every day after school. Do you think I'd do anything to jeopardize their health?"

After 26 years of working in the dry cleaning business, Poling said he has never heard of anyone dying of cancer. "Most of the time, we just get heart attacks from the stress," he said.

To bring about further reductions in the back shop's perc levels, Poling said he would have to get rid of his existing hardware, which is known as a "cold transfer" system because each load must be manually transferred at the end of the washing cycle to a separate drying unit. A newer type of dry cleaning equipment -- grandiloquently known as a dry-to-dry no-vent refrigerated system -- reduces emissions by containing both the wash and dry cycles in a single machine.

The problem is that the dry-to-dry system can handle only smaller loads and takes nearly three times as long as a transfer washer. Just to keep pace with his current volume, Poling would need to install at least two dry-to-dry units, at a cost of about $50,000 each, including installation and renovation of the back shop. Since the machines would be going full bore just to keep up with regular orders, Poling said he would have to eliminate special one-hour orders. "I guess I'm going to have to change the name of the business," he chuckled.

Poling doesn't want to think about raising his prices, but he knows he may have to if forced to make a big capital investment.

Dave Norford, who owns a dry cleaners across the street from Poling's, spent $65,000 to install a dry-to-dry system two years ago -- and promptly raised his prices 5 percent to recover his costs. "It's an incredibly large investment," said Norford. "You absolutely have to pass it on."

But such concerns may be exaggerated, argued David Doniger, a senior staff attorney with the Natural Resources Defense Council, an environmental group. Dry cleaners will see little in the way of pollution control if the EPA gives weight to industry claims of financial hardship, he asserted.

Under currently proposed legislation, EPA would study the financial burden its rules would place on businesses. Essentially, the rules could be relaxed if their impact is deemed catastrophic, but the failure of some businesses would probably be considered acceptable, said Bill Fisher, vice president of a dry cleaning trade group, the International Fabricare Institute in Silver Spring.

In any case, Doniger said, any increased costs of business will be industry-wide, putting Poling on the same footing as his competitors. "Americans are prisoners of dry cleaners," said Doniger. "We have to clean our clothes. If there are small increases of a few cents per garment it will be quite readily passed on" to consumers.

Fisher estimated that about 25 percent of the nation's 25,000 dry cleaners have already installed dry-to-dry machines. The IFI's surveys indicate that existing plants are installing the new technology once their old equipment wears out. In the meantime, the trade group has been pushing those with the old equipment to install vapor absorbers.

"If {the government} tells us vapor absorbers are enough {to meet the Clean Air Act's standards}, we could not in good conscience predict terrible price increases," said Fisher. "That kind of cost can be gradually absorbed. But if everyone has to go with {the dry-to-dry unit}, you're looking at some people going out of business. A potential capital investment of $30,000 to $50,000 is very scary."

Just ask Wayne Poling.