Air Quality and Health

Air quality is an issue of concern for all of us. Healthy people do not normally notice any effects from air pollution, except occasionally when levels increase due to weather or traffic conditions. If so some people may get eye irritation and start to cough with breathing becoming uncomfortable. As most air pollutants are invisible the long term effects are often not appreciated but it remains a significant mortality burden within the UK.


The effects of poor air quality on health increase gradually as pollution levels rise. However for those with lung or heart conditions such as bronchitis or emphysema the effects of poor air quality can be serious. Daily changes in air quality trigger increased admissions to hospital and contribute to the premature death of those who are seriously ill.

It is estimated that the mortality burden from particulate exposure alone in the UK in 2008 was equivalent to 29,000 deaths with an associated loss to the population of 340,000 life years (COMEAP 2010). Public Health England have also released data estimating local mortality burdens associated with particulate air pollution at a local authority level. A copy can be downloaded at the bottom of this page.

More information on the health effects of poor air quality can be found on the links at the bottom of this webpage.

Types of Pollutants

  • Benzene is a hydrocarbon that comes almost entirely from vehicle exhausts.
  • 1,3-Butadiene also comes almost exclusively from vehicle exhausts.
  • Carbon monoxide is the product of incomplete combustion of fossil fuels.
  • Lead was used as a petrol additive, however with the phasing out of this fuel in 2000, ambient concentrations have now dropped significantly.
  • Nitrogen dioxide is formed whenever fossil fuels are burnt in air. The main source in Winchester is from motor vehicle exhausts.
  • Ozone in the upper atmosphere is essential to protect the earth from harmful ultraviolet light. However at high levels near the ground this gas can irritate the airways of the lungs. It is formed as a secondary pollutant i.e. by the reaction of other pollutants with each other.
  • Sulphur dioxide is mainly produced during the burning of coal and oil.
  • Particles or PM10 are small airborne particles that can penetrate deep into the lung. They come from many sources including sea salt, wind blown soil, combustion processes and droplet formation in the atmosphere. However, with Winchester town centre the main primary source is from combustion processes and especially diesel engines.
  • Fine particulate matter or PM2.5 or PM1.0 are the even finer fractions. There has been a recent move towards these parameters as better representing health related issues than PM10. However under current UK law there is no requirement to assess these parameters at a local level.

Further information on these pollutants can be found in the National Air Quality Strategy 2019, which can be downloaded from the DEFRA website. This new strategy introduces an additional focus on other sources of pollution such as domestic fuel burning (PM2.5) and agricultural (Ammonia) as well as industrial and transport related issues.