These combine with existing urban pollution. Environmental sensitivities may be life threatening or mild. While we tend to think about air pollution as an environment issue, it has a direct influence on human health. Human beings can survive for a week or so without food or water, but we can only survive a few minutes without air. The quality of the air we breathe is of major importance to our well being.
Chemical sensitivity can occur following exposure to substances such as formaldehyde.
While it is considered this generally occurs only in an occupational setting following a single acute exposure, chronic exposure to chemicals can cause the same spectrum of effects as a single acute exposure. Asthma can be caused by the same pollutants and the prevalence of this is also growing in the population. This is not surprising as asthma is hypersensitive airways. Many asthma attacks are provoked by allergic reactions and chemical hypersensitivities. Official figures for the percentage of Australian people in the population suffering with chemical sensitivities are unknown.