SHANGHAI - Although their families were against it, the young couple Zhang Xin and Wang Hua rolled up their sleeves and donated blood for Expo 2010 Shanghai, marking their life with meaning.

"My family didn't support our decision. They said I should relax and prepare my body for pregnancy. True, I want a baby But we are in very good health. I don't think it would make a difference to my health," said the 27-year-old woman who works at an exhibition company.

Zhang is a member of a volunteer team formed by the China International Intellectech Corporation, a human resources service company. More than 20,000 white-collar workers in the city joined the team and serve society regularly.

"During the Expo, millions of visitors will come to the city. It is important to ensure the blood reserves, especially the rare blood types, for emergency use. My blood was A type, one of the rare blood types in the city, so I decided to get over my hesitation and signed up to donate," she said.

Full?coverage:

Zhang has donated blood three times, the first time at college. She knows that others have donated more than she has.

"I know my move will affect others and let them know the importance of donating blood to meet emergency and everyday needs," she said.

But 28-year-old Wang Hua had never donated blood before. "At the beginning, I didn't agree with her decision. But pictures she took after the Sichuan earthquake and the stories she learned there really touched me so I eventually changed my mind," Wang said.

Zhang donated her blood for the second time after the 8.0-magnitude earthquake in Sichuan province two years ago. At that time, Zhang and her friends flew to Sichuan and worked as volunteers helping people in need.

The couple said they are also ready to give a hand to the quake-hit Yushu, Qinghai province, in whatever way they can.

The city has reserved sufficient blood for clinical use during the Expo, according to the Shanghai Blood Administration Office.

So far, more than 2,700 liters of blood have been collected, almost doubling the city's regular blood reserves, which usually totals about 1,200 to 1,800 liters, officials said.

"Normally, the clinical demand for blood in Shanghai is about 260 to 300 liters per day. But that is far from meeting the needs of the Expo and its estimated 70 million visitors. In case of any possible emergency, sufficient blood supply is quite necessary," said Chen Qiang, an official with the blood administration office.

His office has formed an emergency team of more than 10,000 members from the city's 19 districts and counties, and 3,000 students from local universities and colleges. They will respond to any emergency in which large amounts of blood are needed.

"As a large number of foreign visitors are coming to Shanghai, the collection and storage of rare blood types is also a crucial issue. Some blood types, such as the RH negative type, are rare in Asian countries, so we must have a sufficient supply for the Expo," Chen said.

Currently, some 60 liters of rare RH negative blood have been stored, an amount that is five times more than the city's regular reserve. Also, a special volunteer team of more than 600 people with RH negative blood type has been established to donate blood in case of emergencies.

The city also established a network with neighboring provinces, including Jiangsu, Zhejiang, Anhui and Shandong. When the city has a dwindling amount of a certain type of blood, the four provinces will provide supplies as quickly as possible, officials said.

Some mobile blood-collection vehicles will be stationed outside the Expo site, and local residents are encouraged to donate blood for the Expo, Chen said.

In addition to recruiting volunteers from the Shanghai area, authorities are also encouraging expatriates in China to donate blood during the Expo.