Air Pollution In The United Kingdom - Essay Example

The conventional methods to study pollution of air by chemical pollutants including heavy metals and other trace elements is by precipitation analysis (Ermakova et al, 51). An alternative method to measure integral trace element deposition is the use of lichens as biomonitors (Sloof & Wolterbeek, 139). Lichens are useful for the research on air pollution since they grow in different climatic zones. Also since they do not have a root system the pollution caused by sources other than the air is negligible.

It has been found by researchers that lichen distribution in urban areas was poor as compared to the neighbouring rural areas (Richardson, 33). Other plants may have a comparatively higher sensitivity to pollution, but llichens are able to reflect the absorbed pollution load over a long period. Air pollution is generally composed of smoke, mineral-rich dust, gases such as sulphur-dioxide, nitrogen oxides, fluorine, ozone, and peroxyacetylnitrate (PAN). Since the 1960s, research studies have revealed that the distribution of particular lichen species is concurrent with sulphur-dioxide levels in most urban areas in the United Kingdom (Hawksworth & Rose, 145).

With increase in the knowledge about lichen distribution in connection with pollution, it has been possible to determine air pollution levels based on the occurrence of particular groupings or assemblages of lichens. Hence, in this research project, samples of lichens were first collected from various sites in urban areas and from rural locations. The frequency and abundance of each lichen specie at the series of sites, was recorded. The collected data about lichen distribution is used mathematically for determing pollution levels.

Instead of distribution data, measurements of conductivity, chlorophyll content or algal cell fluorescence may be used. However these measurements tend to be difficult to interpret because of inherent variability where large numbers of