GREENWICH, Conn. (AP) _ Frank Martin brushed aside the sight of fancy cars and expensive shops and savored what he found most precious in this affluent city.

The retired coal miner took a deep breath. ''The air is so clean.''

''If you stood in my town, after a while you'd look like you were working in a coal mine,'' said Martin, from Lebanon, Va.

''The coal dust really flies,'' agreed his wife, Mavis.

Martin, 54, has a keen appreciation for clean air. He suffers from black lung disease, a debilitating ailment that forced him to retire from the mines nine years ago.

He was in Greenwich on Friday with his wife, his wife's sister and his brother-in-law to picket one last day outside the corporate headquarters of the strike-bound Pittston Co. before heading home.

Martin's benefits have been wiped out and his brother-in-law is out of work as a result of the strike by about 1,700 coal miners in West Virginia and Virginia that began in April.

As part of the United Mine Workers' strike strategy, the union has been bringing up groups of a dozen or so miners and their families to picket outside Pittson headquarters.

Although violence has erupted elsewhere, the Greenwich picket lines have been peaceful.

Martin and his family were part of a group of 13 visiting Connecticut. On the way north, they participated in rallies held by labor unions in Baltimore and Newark, N.J.

The group was divided in three teams upon arrival in Greenwich. Martin and his family formed one team, and they worked three-hour shifts on the picket line daily this past week.

''I would like to live here, if I could afford it. It's a clean town, a nice town,'' said Martin's brother-in-law, Lloyd Blakenship, from Rowe, Va. ''But I like my job. We like the family ties we have down there.''

''We know everybody by name,'' added his wife, Marie.

They said Lebanon and Rowe have about 10,000 residents each. Greenwich, with 60,000 residents, is one of the nation's wealthiest communities and home to many celebrities and top business executives who commute to New York City.

Mrs. Martin and Mrs. Blakenship said they were impressed by the beautiful homes and the variety of shops, although the prices were dismaying.

The average sale price of a home in Greenwich last year was $800,000, while Mrs. Martin said her home - ''one of the nicest homes in Lebanon'' - is on the market for $135,000.

Mrs. Blakenship said everyone in Greenwich drives a nice car, while back home pickups and huge coal-hauling trucks predominate.

Despite the differences, the four said they found Greenwich residents to be friendly. They said motorists blew their horns and gestured support.

The foursome's only hostile words were for Pittston officials, who've declined to meet with strikers. No new contract talks are being held and replacement workers hve been trying to mine the coal.

''They think we're a bunch of dumb hillbillies, but we're not,'' said Mrs. Blakenship.