The Alexandria City Council last week asked the city attorney to study the possibility of drawing up an ordinance similar to one passed recently by Fairfax County which forbids the display of sexually explicit material.

The Fairfax law, approved by the county board of supervisors last month, established a maximum penalty of one year in jail or $1,000 fine or both for violators of the ordinance.

The state of Virginia already has a law prohibiting the sale of so-called "adult magazines" to minors, but that law says nothing about display of such material.

Councilman Nicholas A. Colasanto, a strong backer of the legislation, said the city should move as quickly as possible "to protect our own youngsters from being subjected to this filth."

Councilwoman Ellen Pickering said the purpose of the law would go beyond the protection of children. "It's an absolute affront to a grown woman to go into a store and have to face the vulgar poses and pictures," she said.

But Councilman Donald C. Casey said the state law was explicit about the sale of materials to minors, and he questioned whether the council should spend its time worrying about how salespeople display their merchandise.

"It's getting too far removed from any semblance of any regulation the council should get involved in," said Casey.

In other action, the council deferred a resolution presented by councilwoman Beverly Beidler which would have requested local restaurants to establish nonsmoking areas "wherever such an arrangement is possible." The council agreed to study a model ordinance on the issue written by the Potomac Lung Association before taking any action.