City officials have warned Beijingers not to spit, litter or queue jump as part of efforts to put a gloss on Beijing's image for the Games, but the latest campaign has deeper implications.
Normal Chinese blood supplies will simply be unable to cope in case of accidents or emergencies during the Games, according to city health officials.
"If anything happens, if there are any problems we need to be ready," said Zhu Ruiquan, a department director at the Beijing Red Cross Blood Centre.
China is chronically short of rhesus negative blood, a type certain to be common among the 500,000 foreigners expected here for the August 8-24 Games.
Only 0.03 percent of ethnic Chinese have the type, against 15 percent for Caucasians, he said.
Demonstrating a change in traditional Chinese attitudes, young Beijingers are coming forward to help make up for the shortfall, according to health officials.
Most donors are aged 25-30 and, unlike their parents' generation, they feel a civic responsibility to donate blood and no superstition about parting with it, according to Xu Min, 30, a nurse who has been working for the Red Cross here for four years.
"Traditionally Chinese people see blood as very precious but younger people are different. A lot of people say they are giving blood for the Olympics," she said.
Chinese blood donors virtually did not exist 10 years ago, according to a contemporary US embassy report, and hospitals had to rely on a high-risk market in blood that was bought and sold with little medical supervision.
The process eventually triggered an HIV epidemic in the 1990s affecting millions of people.
Those days are gone, according to Zhu, as hundreds of donors queue up at 14 buses fitted out as mobile blood donations centres in downtown areas.
"No blood is sold anymore -- the only incentive is honour and glory," he said.
However, Gao Yaojie, a retired doctor and veteran Chinese AIDS activist, disputed Zhu's claim, telling AFP in an interview that impoverished peasants still sold blood, even in Beijing.
"Farmers sell blood because they are too poor to make a living and pay school fees for their kids and so on," Gao told AFP in a phone call from Henan province, epicentre of the AIDS crisis of the 1990s.
However, she did not dispute the contention that attitudes may be changing among the younger generation about blood donations, mostly as a result of a massive propaganda campaign carried out throughout the country.
As part of the campaign, a poster covering an entire exterior wall of the blood centre exclaims: "Prepare blood for the Olympic Games and win glory for the country!"
Zhu's centre and three others in the capital have already stored about 500, 200-millilitre bags of rhesus negative blood on ice. They need at least 300 more to be safe for the Games, he said.
Yang Hongjie, 25, is typical of the young people waiting to give blood in downtown Wangfujing Street, a chic Beijing shopping centre.
"Ideas are changing," he said. "If we donate blood, things like the HIV crisis will not happen again. So it is good for the people, good for the country and good for the Olympic Games."