Potentially Deadly Air

A picture of smog from March 2010 and clear skies in June later that year

Now we know the air in Hong Kong is bad -- not as bad as China -- but pretty bad relative to the United States.

Scientists who have studied air samples around China and Hong Kong have found 10 to 20 times more fine metallic particles than the US.

While Hong Kong's PM2.5 levels are lower than most cities on the mainland, it has a higher concentration of health-threatening trace metals. These include zinc and chromium that can cause a range of problems from premature aging to cancer.

Higher concentrations of airborne trace metals can even damage human DNA, thus endangering the genetics in future generations.

The scientists say that without greater environmental regulations, high trace metal levels could become a public health crisis.

Li Weijun, a professor of environmental science at Shandong University has studied nearly every part of China, from the grasslands of Inner Mongolia to Hong Kong's Victoria Peak, collecting samples and examining them. They probably have one of the largest data banks of airborne particles in China.

"Damage to health caused by fine particles is not only determined by the quantity of particles, but also what type they are," he said. "Trace metals are the nastiest things in the air that can damage your health."

With regards to Hong Kong, the PM2.5 pollution, Li believes it could have come from power plants and factories in the Pearl River Delta.

"As long as you have a large number of factories in your neighbourhood, you will have the problem. But even the most advanced technology cannot remove these extremely small particles," he said.

Li published a research paper in the academic journal Environmental Science and Technology last year. In it, his team found 105 micrograms of iron per litre of water in cloud on Mount Tai in Shandong province and 90mcg on Mount Lu in Jiangxi province. At Mount Elden in Arizona, the reading was only 5.6mcg.

In terms of zinc concentrations, 200-250mcg were found on the two Chinese mountains, and none on Mount Elden.

The other metals or hazardous elements in China's air include copper, magnesium, lithium, nickel, cobalt, arsenic and selenium. When mixed with water, zinc can enter human cells via the bloodstream or tissue.

Through oxygen, zinc can damage the structure of DNA in cells and this is irreversible.

Is this not shocking enough for anyone living in China and Asia?

In Hong Kong we always knew the "fog" was smog and then chief executive Donald Tsang Yam-kuen said there was nothing we could do about the air pollution across the border.

But now we know what we're breathing in is potentially dangerous, particularly for babies and young children.

What is the Hong Kong government going to do about this now? The onus is now in Secretary for the Environment Wong Kam-sing and the under secretary Christine Loh Kung-wai to really do something about the air quality here.

Top expats are leaving the city in search of cities with cleaner air for themselves and their families because it's priceless.

We thank Li for this report as it confirms what we already know, but in much greater and scarier detail.

He must also be praised for his extensive research. It wouldn't be surprising to hear if the Chinese government tried to bar him from publishing this work because of its explosive consequences.

Mainlanders are already wary of air quality in China and this report gives further evidence that the country has sacrificed the environment and its people for GDP growth.

We need more people like Li to shake things up and make governments realize that change needs to start now.