Would someone out (more knowledgeable than I am) enlighten me? So, the increased radiation level is 2.3 μSv/hr (20,000 μSv/yr - which is UNDER the safety limit for an occupational worker) in the Exclusion Zone (minimal to no people). The radiation that is being released is coming from (being removed from) the vegetation and ground and being dispersed (diluted) in the air. Also, controlled burns are beneficial for many reasons. So, why is this is bad thing?
ChemTeach; A couple of reasons there;
Exclusion zone limits are based upon external exposures where the primary risk is from penetrating (gamma and beta) radiation. So, some attenuation from tissue is expected.
The exposure at Chernobyl will be gaseous and very fine particulates that are an inhalation risk. Also they will be heavily loaded up with alpha particle emitters that are incredibly energetic and once deposited in the lungs the high energy state of alpha particle decay will cause a persistent exposure (days, weeks, months) until the body can expectorate (cough up) these contaminated particles. In that time, those particle decays are just roasting any tissue they are penetrating. Alpha particles may only be able to go less than a few mm deep in tissue, but they are incredibly harmful.