The air quality in Harvard Square is bad already, and may deteriorate further due to increased automobile traffic generated by more than $85 million in construction during the next few years.

That is the opinion of Karen Altshuler, an environmental quality specialist who two weeks ago completed a state-funded study of the effects that construction on Parcel 1B behind the Kennedy School of Government will have on the Square.

Hold Your Nose

"Harvard Square is one of the worst areas in the state for air quality," said Altshuler, who works for the Boston firm of Skidmore, Owings, and Merrill. She added that unless the city acts to alleviate auto congestion by eliminating several current one-way streets, improving intersections and synchronizing traffic lights, new construction would lead to a further decrease in air quality.

Construction on Parcel 1B, proposed in the mid-1970's as the site of the John F. Kennedy Library and formerly used for Massachusetts Bay Transportation Authority carbarns, has been delayed for the past five years by neighborhood groups concerned about projected increases in congestion in the Square.

But the city planning board this summer formally approved a $60-million design for a condominium-retail-office-hotel complex on Parcel 1B which would generate only half as much additional traffic as had been predicted earlier.

While neighborhood leaders have accepted the Carpenter and Co.'s latest proposal for Parcel 1B--and are also cooperating with Harvard University on plans for a $25 million office and condominium development across from Parcel 1B on Mt. Auburn St.--they remain worried about the increasing potential for unhealthful air quality.

And Richard Easler, transportation coordinator for the city's community development department, said yesterday that "while air quality in any urban area is a problem," he could not determine whether "the Square is any worse off than any other part of the city" because of a lack of monitoring stations.