In a junkyard you could understand it. And in a junkyard, you'd expect it. But in downtown Bethesda? Yes, in downtown Bethesda.

As you enter Trio Copy Centers on Fairmont Avenue by walking up the steps to its second-floor location, the first thing you encounter is a dog.

He's a brindle boxer named Arco. Maybe he's named after the gasoline because he's full of octane. To judge from his vigilance, and that classic, menacing boxer's face, there's little doubt.

Nor is Arco there just for decoration. According to a Trio sales brochure, "Customers who neglect to pet Arco are frowned upon, by both Arco and the management."

How, in these troubled times, can a business afford to scare off customers with a growling dog? Owner Dave Harris says it's all in fun.

"Some people won't come up because I have a dog," says Dave. "The business I lose, so what? I enjoy having him here . . . . I think he contributes to the business by making a friendly atmosphere."

Besides, says Dave, the "frowned upon" passage in the sales brochure shouldn't be taken literally.

"I needed to fill some space in the brochure and I thought it would be fun trying to be the Art Buchwald of Bethesda," Dave said. "I won't turn people away if they won't pet him. If a customer is scared, I just move Arco into another room."

In his next brochure, Dave confided, "I plan to put a photo of Arco wearing sunglasses, saying all the adulation has turned him to Hollywood."

That will certainly end any lingering notions that Arco could be a menace. But why not go all the way? Why not assign Arco a new identity every few months?

I can see it now.

Arco the Yuppie.

Standing guard over Trio Copy Centers in his $55 Nikes, his hand-sewn leather briefcase and his yellow tie.

Or Arco the Punk: a filthy black T-shirt, a form-fitting vest and glow-in-the-dark spiked bowling shoes.

Or Arco the Federal Nerd: Blue pants that are three inches too short, a short-sleeve yellow dress shirt and a building pass hanging around his neck on a chain.

The possibilities are endless. So, thank heavens, is Dave Harris' sense of humor. As for Arco, the thing to remember is that both his mug and his bark are worse than his bite.

Despite rumors to the contrary, the Super Stoppers Club has not run out of members. Levey has just been out of space for the last few weeks. But I can now reveal the names of the following Washingtonians, who have (Hooray! Huzzah!) quit smoking for at least three months.

Carol Henry and Beverly Saunders used to have the habit in a serious way. "When I worked with them at Glen Forest Elementary School in Bailey's Crossroads, they had to smoke so badly that they would sneak into the intercom room," says former coworker Cathy Alifrangis. No more sneaking. Carol and Bev kicked the habit Feb. 1.

Larry Vollmer was "turned in" by sister Kathy, of Riverdale. Larry had been a five-pack-a-day man for 25 years. Good job! Good riddance!

Another family singing the praises of a former fumigator is the Shipley clan. Bernie kicked the habit in February, much to the delight of daughter Janet. "I would like to say congratulations, and perhaps more importantly, thank you, to a man I love very much," Janet writes, from Virginia Tech, where she's a student. What better reason, or reward, eh, Bernie?

Pete Tierney of Northeast is that rare fellow. He made a New Year's resolution to quit smoking and kept it, reports roommate David Mills, who is reaping the atmospheric benefits.

David Godwin, a three-pack-a-dayer, quit in March 1983 and is still clean, reports wife Debra. And if it's hubbies congratulating wives you want, meet Foye and Carole Webb of Falls Church. Foye says Carole quit in February 1984, after 10 years.

Another family nominee: Mike O'Kane of Burke, who quit on Aug. 8, 1983, much to the delight of Anne O'Kane of Annandale, his mom.

Lani Williams is up to 16 smokeless months now, reports her friend Cindy Long of Laurel. Jack George of Mayo, Md., is at 15 months and counting, as is Chuck Sanders. Joan Oday of Rockville is up to 18 months.

Howard Croft is only at nine months. But give the guy a chance. Howard smoked for 42 years before cold-turkeying, report his joyous coworkers, Linda S. Anders and Kathleen M. Cassidy.

Gretchen Eimer of Potomac did it through acupuncture. Peter May of Southeast did it through an American Lung Association program. Elene Makonnen just stopped, as did Arlene Tate and Mary E. Guernica of Falls Church.

Finally, for this go-round, Patty Krolak of Berkshire, Md., assisted by sons Brian and Douglas, congratulates smokeless husband Paul.

Got a nomination? Send it to Bob Levey, The Washington Post, Washington, D.C. 20071.