The House Appropriations Committee quickly approved yesterday a measure to block a proposed reduction in the limit on the number of passengers allowed to use National Airport each year.

The committee left untouched language in the fiscal 1984 Transportation Appropriations Bill that specifically bars a proposal by Transportation Secretary Elizabeth Dole to lower the limit below its current level of 16 million people a year.

The committee's action was a defeat for area members of Congress, who as a group had supported Dole's move in "Dear Colleague" letters to other members. Rep. Frank Wolf (R-Va.) also sent his own letter to members of the committee. Area legislators argue that air traffic should be more evenly divided among National, Dulles International and Baltimore Washington International airports.

Rep. Lawrence Coughlin (R-Pa.), who has said Congress should not interfere with Dole's decision-making, reserved the right yesterday to try to defeat the measure on the House floor. Dole's supporters feel their chances of success would be better there, congressional aides said.

About 13.7 million people now use National Airport each year. Current policy would allow that to grow to 16 million passengers, after which steps would be taken to cut off further expansion. Dole recently proposed cutting the cap to as low as 14.8 million, a move that would not reduce current service levels but would curtail future growth.

Citizen groups favoring phase-down of traffic at National and increased use of Dulles and BWI support the proposed cut. It is opposed by airlines serving National, which see it as an unfair restriction of their business and investment there.

The language retained by the full appropriations committee yesterday would bar expenditure of funds for the purpose of cutting the cap. It was introduced by Rep. Martin Sabo (D-Minn.), whose Minneapolis district is headquarters for two major airlines serving National: Northwest and Republic.