It is well known that Australia is one of the most urbanized societies in the world. What is perhaps less appreciated is that cities are not artificial environments, carved out of the landscape. Cities are built within and from the natural environment, often in the most biodiverse-rich locations. The watercourses, landscapes and diverse habitats for wildlife are intrinsic parts of our urban environments.

Another crucial aspect of urban environments is air quality. This is important for all urban residents, both human and non-human. It is now well known that poor air quality has a serious effect on human health and well-being; it leads to increased disease, decreased happiness and, ultimately, higher mortality rates.

The human cost of poor air quality is also a question of equity: everyone deserves to live in areas with good air.

To date, air quality in Australian cities has remained generally good compared with most cities worldwide. However our major cities already experience occasional episodes of poor air quality. Many areas have levels of fine particles near internationally recognized thresholds, and without attention these problems will only get worse.

This is why I am pleased to be a Clean Air Champion. This program from the Australian Government's Department of the Environment involves a number of selected representatives from academia, industry and the community. Our role is to raise awareness about the challenges we face to improve air quality and promote solutions to this problem.

A key aspect of the Clean Air Champions role is to build support for the proposed National Clean Air Agreement. This agreement will build cooperation between industry and all levels of government to chart a course towards cleaner air in the future. Proposed activities will range from specific emissions controls on some off-road engines, improved standards for wood-heaters and improved reporting of fine particle concentrations. It will also consider how other initiatives can be harnessed to improve air quality.

Another contribution to future air quality comes from the research being undertaken by the Clean Air and Urban Landscapes research hub. The mission of the CAUL hub is to take a comprehensive view of the sustainability and liveability of urban environments. This is a new consortium of four universities: the University of Melbourne, RMIT University, the University of Wollongong and the University of Western Australia. One of our first priorities is the Western Air-Shed and Particulate Study for Sydney to develop improved techniques for monitoring air quality. Initially this study is focussing on the Western Sydney region, an urban centre with a complex mix of air quality issues, but it aims to develop standards and tools that can be used across Australia.

Urban systems are complex. Indeed cities are the most complicated machines that humans have built.

In order to be able to innovate in order to improve air quality we need to understand multiple aspects of these machines from the biological to political. Reducing pollution from one source, such as heavy road vehicles, requires considering how alternative systems function, and the different ways they can meet our human needs. This complexity is why the CAUL hub is a strongly interdisciplinary team, with expertise in urban design, air pollution, urban greening, human health and biodiversity.

This complexity also means that we cannot afford to delay action. Urban infrastructure has a long lifetime; the systems that are being built now will be operating for many decades. The air quality of our future depends on the decisions we are making now.

Main image by David Iliff (CC-BY-SA 3.0)