Key air pollution problems in the early 21st century

This paper explores not only emerging scientific problems but also the difficulties communicating air quality issues into an increasingly sensitive the public and policy arena. The public understanding and trust in air pollution information and indices may be very different to the notions of validity or accuracy that are important for a scientist. We operate in a world where openness requires us to reveal both the difficulties and disagreements in our understanding of the polluted atmosphere. Yet this can be confusing and increase complexity in situations where clear political and social decisions are required. I am going to examine these issues, starting with questions of what substances we regard as pollutants and the difficulties of getting the correct balance of concern given the broadening the base of chemicals emitted to the environment. There are also questions of exposure particularly in terms of vulnerable populations, who may spend large amounts of time indoors, where air is rarely monitored. In contemporary society there are pollution problems that extend far beyond urban areas and we have to consider regional issues such as windblown dusts, smoke from forest fires along with issues of the emission of green house gases and ozone depleting substances. Finally I will discuss the issues of communicating with a concerned public and sceptical politicians and the troubling interface between technological and sociological control. Such complexity is often missed in a maze of seemingly stronger political and social needs.