Nevada scientists help protect China treasures

Thursday, March 3, 2005 | 4:19 a.m.

RENO, Nev. (AP- Two Reno scientists are trying to help protect ancient terra-cotta warriors and horses in China from the modern day threat of pollution.

Judith Chow and John Watson, internationally recognized air quality experts from the Desert Research Institute in Reno, are in Shaanxi Province researching the impact of pollution on the thousands of life-size statues.

A ceremony to launch the collaborative $250,000 two-year research project was held Wednesday in China.

One of the world's greatest archaeological finds, the 2,225-year-old clay figures are displayed at the Terra-cotta Warriors and Horses Museum in Xi'an, one of the 10 most polluted cities in the world, Watson said.

"It's an overwhelming sight because there's so many of them," he told the Reno Gazette-Journal.

Chow said she was surprised by how large the figures were.

"Some are 6-feet-tall, and they all have different expressions on their faces," she said

The terra-cotta clay warriors and horses, along with chariots and weapons, were accidentally discovered in 1974 while local farmers were digging a well near the site of the tomb of Emperor Qin Shi Huang.

Huang unified China, declared himself its first emperor in 221 B.C. and built the Great Wall.

When he became emperor at age 13, he ordered work to begin on his tomb. During the next 38 years, more than 1 million workers toiled on the terra-cotta warriors. Baked in kilns, each of the soldiers has a distinct facial expression.

"The emperor believed in reincarnation, and he wanted an army of soldiers to protect him in his afterlife," Chow said.

Although ground-penetrating radar has revealed a total of about 7,000 figures, only about 1,000 have been unearthed thus far.

During the last 30 years, museum officials began noticing damage to the surface of the statues and mold growing on them. They suspected pollutants were the cause.

"Because both outdoor and indoor pollution is having a dramatic effect on these fine arts, we wanted to study which pollutants are causing the damage and, hopefully, we find a strategy to minimize it," said Frank S. C. Lee, an associate professor of engineering from Hong Kong Polytechnic University.

Some of the pollutants could be coming from the approximately 1.5 million annual visitors to the museum, Watson said.

"One speculation is ammonia from their breath and chemicals from their clothing could be having an impact," he said.

Chow and Watson will try to find out what pollutants are causing damage, their concentration levels and what control measures can be taken to reduce the damage in the future.

They will be working with Chinese experts from Hong Kong Polytechnic University and the Institute of Earth and Environment at the Chinese Academy of Sciences.

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Information from: Reno Gazette-Journal, http://www.rgj.com