Australia's Chamber Sheds Light on Smog

SYDNEY, New South Wales, Australia, December 1, 2000 (ENS) - Australian scientists have built a high tech chamber to understand the chemistry of smog and help predict its precise impact on human health.

Scientists know smog as ground level ozone. Ozone is a natural constituent of the atmosphere and plays a vital function in the stratosphere by protecting life on earth from the sun's harmful ultraviolet rays.


Dr. Dennys Angove in CSIRO's smog chamber. (Photo courtesy Commonwealth Scientific Industrial Research Organization)
But in the lower troposphere and in the presence of sunlight, ozone reacts with nitrogen oxides and volatile organic compounds and becomes a pollutant. These two precursor gases are produced by natural sources such as forest fires and by motor vehicle exhaust and industrial emissions.

As well as harming vegetation, ground level ozone damages human health. It can inflame breathing passages, decreasing the lung's working capacity. Symptoms include shortness of breath, pain when inhaling deeply, wheezing and coughing.

It is especially harmful for seniors, children, asthmatics and people with heart and lung conditions. High levels of ground level ozone can result in increased emergency department visits, hospital admissions and, in severe cases premature death.

In major North American cities, such as Toronto, ground level ozone is responsible for 1,000 premature deaths annually, with another 5,500 hospitalized.

Now scientists at the Commonwealth Scientific Industrial Research Organization (CSIRO) have built a chamber to help understand the complexities of air pollution.

"There is a range of compounds that make up airborne pollution and, in Australia, emissions of some of these compounds remain unregulated," said Dr. Dennys Angove of CSIRO, the Australian government's research arm.

"We will use the smog chamber to investigate a range of synthetic atmospheres comprising naturally occurring hydrocarbons and hydrocarbons from human produced sources.

"This will advance our knowledge of the different airborne compounds and how each reacts or changes in the atmosphere. It will also help us understand what happens to the compounds once they have broken down or reacted with the cocktail of chemicals that exist in our air."

At high enough concentrations, many pollution causing gaseous compounds are harmful to animals and plants. Some, like 1,3-butadiene, are known carcinogens.

Air pollution and its impact depends on a host of factors, including the pollutant source, reactions in the atmosphere, transport by winds, and removal by clouds, rain, plants and soil.


Toronto's famous landmark, the CN Tower, is barely visible during heavy smog. (Photo courtesy Environment Canada)
Angove said CSIRO's chamber will give atmospheric chemists a greater understanding of how these potentially toxic materials are transported and transformed in the atmosphere. This knowledge will eventually help authorities predict when airborne substances could become harmful.

The CSIRO chamber has attracted significant international interest from the United States and Spain, where one of Europe's best known smog chambers is situated, said Angove.

"The entire area of research into air pollution is now being based around risk assessment. The big question being asked is - how long can you be exposed to something before it harms you?

"The only way to answer this is to know the chemistry of these substances in the atmosphere - a difficult job as they only occur in trace amounts.

After years of study, considerable conflict among medical experts over the health impacts of the various components of air pollution remains.

"One thing scientists have learnt is that smog is a complex creature that is forcing science to its innovative limits in an effort to understand it," said Angove.

"Twenty years on we are still trying to understand the complexities of these air toxics. This new chamber will hopefully raise awareness and understanding of just what we are dealing with on a daily basis," says Dr Angove.