I asked Perplexity,

CPM stands for Counts Per Minute, which is a measure of the number of radiation detection events registered by a Geiger counter or similar radiation measuring instrument in one minute15. ACPM likely stands for Adjusted Counts Per Minute, though this is not explicitly stated in the search results. CPM is a raw measurement of radiation events detected by the instrument, but it does not directly indicate the strength or type of radiation5. The CPM value depends on factors such as: The type and sensitivity of the detector used6 The type of radiation being measured (alpha, beta, or gamma)1 The distance between the detector and the radiation source3 ACPM is probably an adjusted value that takes into account some of these factors to provide a more standardized or comparable measurement across different instruments or situations. However, without more context about the specific chart or instrument you're referring to, it's difficult to say exactly what adjustments are being made to calculate ACPM. It's important to note that CPM alone is not a reliable indicator of radiation dose or health risk. For that, measurements in units like microsieverts per hour (μSv/h) or millirems per hour (mR/h) are more appropriate

Yea but how the f do you read the damn map

Sometimes when you go to this site you will see "normal readings" and then just hours later significant "blooms" of radiation posted. How are these individual sites on the map populating their readings? Is there really high radiation in these areas?

Probably instruments in use,they give off much more radiation.