The aluminium, potassium, sulphur, titanium, and vanadium contents of the lichens Cladina arbuscula (Wallr.) Hale and W. Culb., Evernia mesomorpha Nyl., and Hypogymnia physodes (L.) Nyl. were determined for up to 69 sites in the Athabasca oil sands area in northern Alberta. The element accumulation by these lichens was related to both gaseous and particulate emissions from industrial sources and to a localized windblown dust component. The deposition of atmospheric emissions around an oil-extraction plant as measured by lichen thallus concentration closely followed the distribution patterns measured by physical and chemical methods. Visible changes in the thallus condition appeared to be related to the element concentrations.