Assessing Air Pollution in the Blackbrook Valley

Abstract

This thesis describes methods for assessing air pollution levels in the Blackbrook Valley, near Dudley in the West Midlands. The research forms part of a long-term environmental monitoring programme coordinated by the Nature Conservancy Council. Literature is examined on the methods used to obtain air pollution data, in particular, the compilation of an emission or sources inventory. Although the purpose—collection of emission inventory data and direct measurement of ambient air concentrations are reported to be the most exact methods, these were found to be cost-prohibitive. Alternative methods of data collection, e.g. by calculation were considered. A biological method, using lichen boards to monitor the pollution-induced colour changes in Hypogymnia physodes, was examined in detail. A methodology for this approach was developed from the literature and a survey was implemented in the winter of 1983/84. The results obtained justified the adoption of the basic methodology and suggested a number of modifications to the practical survey procedures. A more extensive survey was undertaken in the winter of 1984/85. Improvements to the board design and recording procedures permitted more detailed observations of lichen damage than were obtained for the first survey. The survey results revealed significant, and widely varying, differences in the levels of lichen damage throughout the Blackbrook Valley. These differences could not be explained in terms of known geographical and meteorological data for “the area. Both surveys showed the same mean level of lichen damage. The data obtained provides a basis for future comparative assessment of air pollution in the Blackbrook Valley. The lichen board technique, as described, provides a simple and inexpensive method for measuring relative pollution levels, which could be employed for periodic or occasional surveys.