Australia’s metropolitan cities all experience episodes of poor air quality (measured in terms of particulate pollution, or pollution by ozone and its precursors NOx and VOCs). The frequency, duration and severity of these episodes are strongly influenced by short-term meteorological conditions (principally temperature and wind conditions), in combination with local topography. Air quality is usually restored to acceptable levels once the immediate conditions change. In this context, our major urban airsheds are highly ‘resilient’, in terms of the common dictionary definition of the word. In contrast, application of the ecologically meaningful terms ‘resilience’, ‘sensitivity’ and ‘adaptability’ to the atmospheres of urban places is not particularly helpful in understanding either their dynamics or the effects of localised or widespread inputs of pollutants. However, if urban air pollution is considered from the perspective of the humans who cause most of it and are impacted by it, then resilience is a more useful concept.
Human resilience in the face of prolonged or recurring exposure to air pollutants is limited. Individuals vary in their sensitivity to exposure to particular air pollutants, with those most sensitive accounting for the great majority of the observed deaths and illness attributed to poor air quality. Unfortunately, our capacity to adapt to unacceptably high levels of air pollution is inherently limited. We can leave the affected area, shelter indoors (of limited value without effective air filtering), avoid strenuous exercise, wear face masks and, in the case of asthmatics and others with respiratory ailments, take prescribed medicines. Although necessary during periods of very poor air quality, these short-term adaptive strategies are not substitutes for action to mitigate the pollution at source through a range of regulatory and nonregulatory measures.