Lichens are useful biomonitors for semi-volatile organic air pollutants, particularly polyaromatic hydrocarbons
(PAHs), as a result of their ability to respond to air pollutants at different levels, their slow growth
rate, their longevity and their ability to indicate the presence and the concentrations of these pollutants.
Consequently, there has been a recent global trend in environmental analytical research to utilize
lichens in this way, with Soxhlet and ultrasound-assisted extractions being the most common analyte
extraction techniques. A wide range of total PAH concentrations has been determined in lichens from
different environments, although phenanthrene, fluoranthene, naphthalene and pyrene tend to dominate
the PAH profiles, with higher 2-ring and 3-ring PAH concentrations than 6-ring. In order to facilitate
inter-study comparison, there is a need to develop a reproducible, sensitive analytical method for organic
pollutants in lichens.