Abstract: This application relates to the detection of electromagnetic pollution. The invention provides apparatus for monitoring electromagnetic radiation comprising: collection means for sensing electromagnetic radiation within a range of frequencies, means for demodulating the amplitude changes, and means for converting the resultant signals to audible and/or visual indications of the nature and intensity of the radiation sensed by collecting means. The apparatus provided can measure the overall quantity, quality and content of the radiation at any location, with the results presented as visual and/or audible signals. FIG. 1 is a block diagram of apparatus in accordance with the present invention.