Leasing in Fairfax County of office and industrial space continued at a healthy pace during the second and third quarters of 1982, despite the general softening of business expansions, according to the Fairfax County Economic Development Authority's latest office space review.

The review covered the period from March through October 1982.

Absorption of space continued at a strong pace, with more than 600,000 square feet leased since the last review. This space was distributed as follows: 152,622 square feet that was leased was previously occupied space; 221,462 square feet of the space was recently completed; 198,000 square feet of space still is under construction, and 44,000 square feet of the total is planned.

Construction starts of high-tech and industrial space also increased, the report said. As of October 1982, 623,650 square feet in nine buildings was under construction in Fairfax County. Of this amount, 198,000 square feet was leased. These projects will be completed within five months and were located in the Dulles, Merrifield, Newington and Reston areas. Lease rates quoted for this space ranged from $4.25 to $6.50 per square foot.

In addition to space readily available and space under construction, 1.7 million square feet was planned for delivery within the next 12 months.

The authority estimated a potential annual absorption of 1,000,000 square feet for industrial speculative space with a vacancy rate of 7 percent. Total inventory as of October 1982 was approximately 17 million square feet.

The authority has defined high-tech and industrial space as that which would accommodate research and development, testing and laboratory facilities, light assembly, manufacturing and processing space, and wholesale and distribution activities.

The summary reported only those basic high-tech and industrial buildings with space for lease.