Consequences of poor air quality
The air we breathe is made up of a complex mix of gases and fine particulates. Some of these are beneficial, some are harmful pollutants and other, such as pollen, that have both benefits and detrimental effects. Pollutants that affect our air quality come from both natural and man-made sources.
The costs of air pollution
Poor air quality has consequences for people's health and wellbeing as well as for our surrounding natural and built environment. The health consequences of polluted air are well documented, and were ably demonstrated by the London smog's of the late 19th and early 20th century. The worst of these events was shown to be responsible for many thousands of deaths. These historic smog's were caused by the large scale burning of coal and wood and were a highly visible example of air pollution and its health effects.
Many of the pollutants of concern today are invisible to the eye but act as respiratory irritants, which are particularly problematic if individuals have pre-existing medical conditions or other vulnerabilities.
The Committee on Medical Effects of Air Pollution (COMEAP) report "Mortality effects of long term exposure to particulate air pollution in the UK" found that the burden of manmade particulate air pollution on mortality in 2008 was equivalent to nearly 29,000 deaths in the UK at typical ages and an associated loss of total of population life of 340,000 life-years. The Royal College of Physicians' report "Every breath we take take: the lifelong impact of air pollution" puts the figure at 40,000 deaths per year and the cost to health services and business at more than £20 billion.
The economic costs of air pollution are not immediately apparent. There are wide ranging indirect costs to the economy such as loss of income to individuals and to businesses through sickness absence / loss of productivity; traffic congestion as transport is takes longer or is delayed; repairs to infrastructure due to physical damage such as that caused to buildings by acidic rain and wider burdens associated with climate variation such as flooding.
The contribution of air pollution to the severity of illness and to the costs for health services and wider society are not yet well understood by the medical and scientific community. In 2010 the House of Commons Environment Audit Committee estimated the health costs of air pollution in the UK as being in the region of £8-£20 billion per year. It is often those at the lower end of the equality spectrum that live in the poorest housing, in areas where traffic is heavier and so experience less positive health and wellbeing outcomes. In tackling air quality, we need to consider health inequalities and ensure these do not widen by working closely with public health professionals.
Pollutants of concern in Wiltshire
The air quality in Wiltshire is predominantly very good, with the majority of the county having clean, unpolluted air. There are, however, a small number of locations where the combination of traffic, road layout and topography result in pollutants being trapped so that concentrations increase to unacceptable levels.
The pollutant of most concern within Wiltshire is nitrogen dioxide (NO2). This is a product of combustion of fossil fuels and the primary source in Wiltshire is road vehicles. Levels tend to be highest on the main arterial roads through Wiltshire towns, where dwellings are direct onto streets, without a garden; the height of the buildings is higher than the width of the street; and there is slope or hill so engines are under greater pressure when climbing.