We're on the verge of the month that haunts Bill Sullivan's dreams.

In August, more cars are on our roads than in any other month. Because many of them are being driven by young people, or drunken people, or both, more cars are involved in accidents during August, too. So August is the month when Washington needs blood the most.

It is also the month when Washington gives the least.

"People are just not aware," says Sullivan, who has been director of blood services for the Prince George's County Red Cross for the last 13 years. "They go on vacation and they think the donors don't.

"What they don't understand is that the donors are them."

Nowhere is the August falloff in donations more acute than in Prince George's. The District's Red Cross chapter can run blood drives at huge federal agencies. Other suburban chapters can tap major companies that employ thousands of people in one place.

But Prince George's does not have many massive employment centers where it can send its nurses and bloodmobiles. And many of its residents work downtown. They can truthfully say they gave at the office.

The county's biggest single office complex -- the Census Bureau in Suitland -- is a welcome six-times-a-year contributor. But Andrews Air Force Base runs its own blood drives, and the University of Maryland is a shadow of its normally bustling self during the summer.

So during August, when the need is greatest, the county chapter is relegated to drumming up blood at churches, veterans organizations and Lions Clubs. Loyal and red-blooded folks turn out at these places, to be sure, but seldom enough of them to produce as much as 100 units of blood per day-long visit. One open-heart operation can require 200 units in an hour.

"Most donors are sincerely altruistic," said Sullivan, as he sipped coffee in his Hyattsville office. "But there is a segment that says, 'What's in it for me? I'm not going to donate blood for somebody down the street that I don't even know.'

"How to increase our donations is a problem that we think about all the time. You know, people say, 'Why don't you just go park a bloodmobile in a shopping center like Prince George's Plaze?' The reason is that people go there for a purpose, like to buy a pair of shoes. If we put a bloodmobile there, they might peek in. But once they find out it takes 45 minutes to an hour to give blood, they'll probably decide that's too long."

Why not pursue donors at swimming pools, where able-bodied teenagers hang out? "Because you shouldn't go swimming again for four hours after blood is drawn," Sullivan said. "Show me a kid who goes to a pool so he can't go swimming."

The only answer, says Bill Sullivan, is for people to search their consciences and simply resolve to give. I second the motion -- emphatically.

Anyone in the Washington area between 17 and 66 is eligible. And you don't have to live in Prince George's. The area's blood is all collected and stored at a central warehouse near the State Department, but they'll take whatever they can get, from whoever wants to give it.

To donate to the Red Cross chapter in your area, find the appropriate phone number below: Washington: 857-3553. Prince George's: 559-8500. Montgomery: 588-2515. Alexandria: 549-8300. Arlington: 527-3010. Fairfax: 591-8091. Prince William: 368-4511. Loudoun: 777-7171.

Thanks in advance.

Paul S. Green of Bethesda writes that he was taking his morning constitutional at Dupont Circle the other day when he passed "a slightly befuddled panhandler lounging on the sidewalk.

"'Hey fella,' he called out cheerfully. 'Got some loose change? Need it for a drink for break. . .' He stopped and hastily corrected himself, 'Need it for breakfast.'

"'Right the first time,' I thought. And kept on walking."

Gordon Barnes please note: Nancy Khan of West Lanham Hills has devised a new way to measure air pollution in Our Town. "Coming over the railroad tracks on New York Avenue NE, just before Florida, I look to see if I can see the Washington Cathedral. If I can't, we're in trouble."