Taking Control of City Air Pollution

To achieve its goal to cut greenhouse gas emissions by 60 percent in the Sydney, Lower Hunter and Illawarra regions before 2050, NSW still needs to work on reducing ground-level ozone and particle pollution.

One of its heaviest sources of this kind of pollution is traffic fumes, a problem which China can relate to.

Motor vehicles are one of Australia's largest contributors to city air pollution: in Sydney, one of Australia's most traffic- congested cities, petrol-run passenger cars are responsible for more emissions than all other vehicles combined.

Bridgman says this is a common problem for many cities worldwide, including Beijing and Shanghai; and the problem tends to escalate during traffic jams when people are driving to and from work.

"From the traffic you get nitrogen oxides and various types of hydrocarbons. When that occurs under the right conditions, particularly in the summer time when you have warm weather and lots of sunshine, then you'll get photochemical smog," he said.

"For cars, some of the developments include better ways of controlling emissions through catalytic converters, and cars that are more efficient in burning fuel.

"Unfortunately, that's often offset with an increasing number of cars in urban areas," he added.

Keeping cars tuned and driving less immediately reduces exhaust pollutants; well-maintained cars are likely to emit between 9 and 25 percent less pollution than poorly maintained vehicles. Greater fuel efficiency is an added money-saving benefit.

To combat the problem of traffic emissions, NSW introduced a " Cleaner Vehicles and Fuels Strategy" in 2008 to promote cleaner cars and fuels, and improve roads, housing and public transport " to reduce vehicle dependence and traffic congestion."

The state raised vehicle emissions standards and upgraded their own fleet of cars and buses to lead by example. This plan aimed to save substantial costs and reduce greenhouse gas emissions by more than 55,000 tons over three years through increased fuel efficiency, with a 20% improvement in overall environmental scores.

NSW also introduced an environmental rating for heavy vehicles, with a fuel rebate scheme to encourage retrofitting of diesel engines to reduce dangerous particle emissions.

For a better insight into the problem, remote sensors were installed on roadsides -- revealing that older vehicles were responsible for a disproportionate amount of pollution. Solving this kind of issue would require greater public awareness.

Community awareness and behavior-change programs promoted fuel efficiency, buying cleaner vehicles, properly maintaining vehicles and active transport such as walking and cycling. Annual cycle, bus or walk to work days were also introduced, to encourage people to break the habit of relying on their cars for transport.

According to Bridgman, part of Sydney's success in raising its air quality is attributable to greater public awareness of the health and environmental risks that accompany city smog.

"They've become more knowledgeable about the sources of pollution, and they're becoming more vigilant in terms of watching what's going on. And they've also become more noisy -- more willing to complain," he said.