Trichloroacetic acid (TCA), secondary air pollutant (SAP) and a product of photooxidation of volatile chlorinated C-i-hydrocarbons has phytotoxic properties and negatively influences on the state of forest health in general. The present knowledge shows the uptake of TCA by the spruce from the atmosphere by precipitation over soil, roots, and transpiration stream up into needles, where it effects the photosynthetic apparatus of the plant. To judge the role of TCA in forest ecosystems its effects along with other stressors must be followed. Those include, above all, emissions of sulphur oxides and fluoride from burning energetic coal. From monitoring the selected stressors - the content of total sulphur, fluorine and chlorine besides TCA - in spruce needles on selected stands, a positive correlation between the needle loss (as a measure of the spruce forest damage) and the content of S, F, and TCA was found. In this way the negative effect of TCA was conflrmed.