Here is a list of school and library closings and curtailed, emergency operating hours for major shopping centers - announced yesterday at the close of business - because of the natural gas shortage and conservation efforts. Many smaller businesses and retail firms plan to operate at reduced hours. Persons should call individual firms for information. Other changes may be announced later this week.

District of Columbia - St. Martin's school is closed all week.

Alexandria - Three schools will be closed all week. Today students from Barrett will report to Jefferson-Houston Elementary School and students from MacArthur will go to Robert E. Lee Elementary School. Most students from the occupational center will go to T.C. Williams High School.

Students who normally walk to Barrett should report there at regular hours for bus rides to Jefferson-Houston. Barrett school bus riders should be at their regular bus stops one hour and 15 minutes later than usual. Students who walk to MacArthur should report to MacArthur for bus rides to Robert E. Lee. MacArthur bus riders should be at their regular stops 15 minutes later than usual. Occupational Center students should ride the regular T.C. Williams buses.

Arlington - The Arlington School Board was meeting last night to decide whether to close schools. School employees who normally work when schools are closed because of heavy snowfall are asked to report to their jobs.

Fairfax County - Four schools will be closed today: Robinson Secondary School and Belle View, Forest Edge and John C. Wood Elementary Schools. Four libraries will be closed through Saturday: the central library in Fairfax City, the Richard Byrd Library in Springfield, the Thomas Jefferson Library outside Falls Church, and the Kings Park Library in Burke. For information on the hours of other libraries call 691-3187.

Starting Wednesday, students at the Forest Edge Elementary in Reston will go to Hunters Woods school, Reston, from 1 p.m. to 5 p.m. Regular Hunters Wood students attend school from 8:40 a.m. to 12:40 p.m. Students at John C. WOod elementary in Fairfax City will be shifted to two schools.Kindergarten and first grade students will go to Layton Elementary across the street and the rest will go to Fairfax High School. Students at Robinson Secondary will go to Woodson High School from 12:30 p.m. to 4:30 p.m., with Woodson students attending in the morning. Robinson intermediate students will attend Frost intermediate from 1 p.m. to 5 p.m., with Frost students attending in the morning. Belleview Elementary's kindergarten through third grade studnets will go to Quander Road Elementary and fourth through Sixth grades will go to Cameron Elementary. The students in the gifted program will go to Cameron and the preschool special education pupils will go to Bucknell Elementary. The shifts are scheduled from Wednesday through Friday.

Falls Church - All four public schools will be closed all week. The Falls Church Public Library will be closed today and open Wednesday through Friday from 9 a.m. to 9 p.m. and Saturday from 10 a.m. to 2 p.m.

Montgomery County - Fifteen gas-heated public elementary schools will be closed today. They are: Chevy Chase, Forest Grove, Hungerford, Montgomery Knolls, Piney Branch, Pleasant View, Tuckerman, Rock Creek Forest, Somerset, South Lake, Strathmore, Summit Hall, Takoma Park, Wheaton Woods and Whittier Woods. The 15 public schools will be closed today and open Wednesday through Friday from noon to 8 p.m. The two senior recreation centers also will be closed today.

Prince George's County - Most schools will be open as usual this week, but students are asked to dress warmly. Schools that will be closed today are H. W. Wheatley Special Education Center, Princess Garden Special Education Center and the Hillcrest Heights Special Education Center. Nine elementary schools will be closed today: Robert Frost, Samuel F. B. Morse, Paint Branch, Seat Pleasant, Patuxent, Pointer Ridge, William Beanes, Camp Springs and Francis T. Evans elementary schools. STORES AND SHOPPING CENTERS

Giant - In Virginia, they will be closed SUndays and open from 2 p.m. to 8 p.m., Mondays through Thursdays, from noon to 8 p.m., Fridays, and 10 a.m. to 6 p.m., Saturdays.

Safeway - In Virginia, they will be closed Sundays and open from 2 p.m. to 8 p.m., Tuesdays through Thursdays, and from non to 8 p.m., Fridays and Saturdays.

Grand Union - In Virginia only, they will be closed Sundays and open from noon to 6 p.m., Mondays 1 p.m. to 6 p.m., Tuesdays and Wednesdays, noon to 8 p.m., Thursdays and Fridays, and 10 a.m. to 6 p.m., Saturdays.

A&P - In the District of Columbia and most of Maryland they will be open from 9 a.m. to 9 p.m., Mondays through Friday and Sunday hours remain the same.

ABC Stores - Will be open from 11:30 a.m. to 6 p.m., Mondays through Saturdays.

Dart Drug - In Virginia, they will be open from 1 p.m. to 6 p.m., Mondays through Fridays, 10 a.m. to 5:30 p.m., Saturdays and Sundays except for 1735 N. Lynn St., Arlington, which will be open from 11 a.m. to 6 p.m., Mondays through Fridays and noon to 5 p.m. closed Sunday, 7271 Arlington Blvd., Falls Church, will be open from 1 p.m. to 6 p.m., Mondays through Fridays, and 6 p.m. to 1 p.m., Mondays through Fridas for prescriptions only.

People's Drug Stores - In Virginia, noon to 8 p.m., Fridays, 10 a.m. to 6 p.m., Saturdays and noon to 6 p.m. Sundays. At the discretion of store managers in certain districts where there is more than one People's, one will close on Tuesday or Wednesday.

Drug Fair - In Virginia times have been posted in the stores and vary from store to store.

Springfield Mall and Tysons Corner Shopping Center - Most of their stores will be closed today. They will be open from noon to 5 p.m. Sundays, 2 p.m. to 8 p.m. Mondays and Wednesday, 2 p.m. to 9 p.m. Thursdays and Fridays, and from 11 a.m. to 8 p.m. Saturdays, Bloomingdale's will be open from noon to 5 p.m. today.

Lord & Taylor store at Seven Corners: It will be open today, Wednesday and Friday from 11 a.m. to 5 p.m. On Thursday it will be open from 11 a.m. and on Saturday from 10:30 a.m. to 5:30 p.m.

Hecht and Woodward and Lothrop department stores: In Virginia, their stores will be closed today and open from noon to 5 p.m., Sundays, 2 p.m. to 8 p.m. Mondays, 2 p.m. to 9 p.m. Thursdays and Fridays, and from 11 a.m. to 8 p.m. Saturdays. The Pentagon store will operate as usual. The Seven Corners Woodies will be closed Sundays as usual and open Tuesdays from 2 p.m. to 7 p.m., and the rest of the week will follow the same schedule as the other Virginia stores.

Sears - In Virginia they will be open from 2 p.m. to 8 p.m. today through Friday and from 10 a.m, to 8 p.m. on Saturday.

Hechingers - The seven Northern Virginia stores will be open today, Thursday and Friday from 3 p.m. to 9 p.m. and will be closed Wednesday. Saturday and Sunday hours will be from 10 a.m. to 6 p.m.

Garfinkel's - Tysons Corner will be closed today and open from noon to 3 p.m. on Mondays and Wednesdays, 1 p.m. to 9 p.m. Thursdays and Fridays and from 11 a.m. to 7 p.m. Saturday. Seven Corners will be open today from 2 p.m. to 8 p.m., 2 p.m. to 9 p.m. on Thursdays and Fridays, and from 10 a.m. to 6 p.m. Saturdays. Springfield will be closed today and open from noon to 6 p.m. Wednesday, 11 a.m. to 9 p.m. Thursdays and Fridays, and 11 a.m. to 7 p.m. Saturdays. MUSUEMS

Mount Vernon - 10 a.m. to 3:30 p.m., grounds close at 4 p.m.