The Senate Appropriations Committee yesterday approved a $1 billion emergency housing program opposed by the White House, and voted to wipe out the automatic $75-a-day tax deduction for congressmen for living expenses while in Washington.

Defying a veto threat, the Republican-controlled committee duplicated the Democratic-controlled House and voted the $1 billion in immediate fiscal 1982 funds for a mortgage subsidy program to stimulate housing construction.

The provision was passed without dissent; repeal of the $75-a-day deduction, made available to members of Congress last year, was the most bitterly fought issue in the bill.

Sen. William Proxmire (D-Wis.) initially proposed to cancel the $75 provision and restore the old ceiling of no more than $3,000 in deductions per year.

But Sen. Jake Garn (R-Utah) said the effect of the $75-per-day provision had been grossly distorted by the press, with the result that it seemed that members were getting huge deductions when, in fact, most were not getting big deductions at all. He said his deduction under the new formula was only $3,822.

Sen. Mack Mattingly (R-Ga.) then offered a substitute for the Proxmire proposal. The substitute would allow members to deduct any ordinary and necessary expenses they can verify, with no ceiling, in place of the automatic $75-a-day deduction. It carried 13 to 9.

Garn, angrily referring to what he termed misstatements in the press about the $75-a-day deduction, said: "For those running for reelection, this is a helluva issue," but for "$3,800 I'll be damned if I'm going to take this crap."

The committee also included in the supplemental money bill for fiscal 1982 language requiring that Poland be declared in default before the federal government makes good any further loans to Polish entities by U.S. banks, except if the president certifies that the payoff was in the U.S. national security interest.

The committee, in approving the bill, also included provisions to:

* Block dissolution of the Bureau of Alcohol, Tobacco and Firearms; the National Rifle Association had originally sought such a dissolution and then reversed itself. Sources said the administration had agreed to put aside its planned reorganization for now because it did not like any of the compromises proposed by members of the committee.

* Appropriate $1.3 billion for guaranteed student loans, the same amount as the House and about $300 million more than the president wanted.

* Allow more subsidized housing for the poor--separate from the new mortgage subsidy program--than the president had sought, though not as much as in the House bill.

* Provide $2.4 billion for sewage treatment plants and $1 billion for extra food stamp costs, both figures sought by the president.

* Appropriate a small amount for "Operation Exodus," to halt the flow of U.S. technology to the Soviets, small extra amounts for the National Archives, maternal and child health programs, and for subsidies to avoid price increases for reduced-rate mail.

* Include language barring the Federal Trade Commission from shutting any of its regional offices.

* Provide $210 million not sought by the president for the highly popular older Americans community service employment program..

The $1 billion in budget authority for the new mortgage interest program was offered as an amendment by Garn, chairman of the Senate Banking Committee, as the first installment of a $5 billion plan already approved by the panel to spur construction of 400,000 new homes.

Although the actual appropriation contained in yesterday's money bill was only $1 billion in fiscal 1982, the entire legislative text of the $5 billion plan, sponsored by Sen. Richard G. Lugar (R-Ind.), was also included in the money bill so that it could be given a long-range authorization without going to the floor separately.

Although yesterday's Senate committee bill appropriated $6.2 billion overall for new programs, it rescinded so much past budget authority for subsidized housing for the poor that its net impact was actually minus $1.4 billion in authority.