NEW YORK (AP) _ At O'Hare International Airport in Chicago, ambulances are sent on emergency runs on an average of two or three times a day.

At Hartsfield Atlanta International Airport, paramedics last year responded to 1,572 calls and transported 618 people to hospitals.

At LaGuardia Airport in New York City, paramedics respond to an average of one or two cases a week where stricken passengers are taken from planes.

At the nation's busiest airports, paramedics don't have to rush to emergencies. The emergencies come to them.

''The biggest percentage of our runs are planes coming in with passengers who have problems while up in the air,'' said Kathy Minogue, a paramedic at O'Hare.

In December, one of three airport ambulances at O'Hare was dispatched for 42 medical emergencies, 31 cuts and fractures, one mentally disturbed person, four cardiac emergencies and 13 special duties, such as flights with landing problems. Medical emergencies include allergic reactions, high fevers and all problems not in the other categories.

At Hartsfield in Atlanta, two-thirds of emergencies involve airline passengers, said Deputy Fire Chief Thomas Brown. Of the 1,572 calls last year, 21 were heart attacks and six were respiratory arrests.

At the Los Angeles airport, paramedics are dispatched ''a couple of times a day,'' said Vince Marzo, a spokesman for the Los Angeles Fire Department. He estimated that life-threatening emergencies occurred twice a month.

Although ambulances at the major airports are equipped with life-sustaining equipment, passengers at most airports must be taken to hospitals for treatment. Of the nation's 25 largest airports, 16 had no doctor on duty and six had no ambulances, according to testimony at a hearing on airline safety last year before the House Subcommittee on Aviation.

Spokesmen for the airline industry say a stricken passenger on a domestic flight is never more than a half hour from an airport where help is available. ''You'll find that's not unfavorably comparable to some of the response times in some metropolitan areas,'' said Tom Tripp, a spokesman for the Air Transport Association.

But some industry observers say the landing time must be added to the time it takes an ambulance to get from the airport to a hospital. Dan Smith, manager of consumer affairs for the International Airline Passengers Association, said, ''If we're going to have the pilot try to put the aircraft down in 20 minutes, we hope emergency help won't be another 20 minutes away.''