A report on a portion of a study on the effect of industrial emissions discusses the reaction of rain, the quantity of sulfur and fluoride per unit of soil, the salubrity of epophitic lichens (Hypogymnia species) used as bioindicators, and the number of sulfur and nitrifying bacteria in the soil. Observations indicate a change in the reaction to rain and increased quantities of sulfides and fluorides caused by the Police Chemical Works. A reaction of bioindicators and an increased number of sulfur and nitrifying bacteria which accelerate the deterioration of architectural monuments and permit occupation by other non-neutral microorganisms have been noted.