Officials used hydrometeorological data to create an image of what the potential nuclear fallout looked like after the Chernobyl disaster in 1986. Using this method, they were able to determine the distribution of radionuclides in the surrounding area, and discovered emissions from the nuclear reactor itself. These emissions included; fuel particles, radioactive gases, and aerosol particles. The fuel particles were due to the violent interaction between hot fuel and the cooling water in the reactor, and attached to these particles were Cerium, Zirconium, Lanthanum, and Strontium. All of these elements have low volatility, meaning they prefer to stay in a liquid or solid state rather than condensing into the atmosphere and existing as vapor.
* Cerium and Lanthanum can cause irreversible damage to marine life by deteriorating cell membranes, affecting reproductive capability, as well as crippling the nervous system. 
* Strontium in its non-nuclear isotope is stable and harmless, however, when the radioactive isotope, Sr, is released into the atmosphere it can lead to anemia, cancers, and cause shortages in oxygen.
* The aerosol particles had traces of Tellurium, a toxic element which can create issues in developing fetuses, along with Caesium, which is an unstable, incredibly reactive, and toxic element.
* Also found in the aerosol particles was enriched Uranium-235.
* The most prevalent radioactive gas detected was Radon, a noble gas that has no odor, no color, and no taste, and can also travel into the atmosphere or bodies of water. Radon is also directly linked to lung cancer, and is the second leading cause of lung cancer in the populace.
All of these elements only deteriorate through radioactive decay, which is also known as a half-life. Half-lives of the nuclides previously discussed can range from mere hours, to decades. The shortest half-life for the previous elements is Zr, an isotope of zirconium which takes 1.4 hours to decay. The longest is Pu, which takes approximately 24,000 years to decay. While the initial release of these particles and elements was rather large, there were multiple low-level releases for at least a month after the initial incident at Chernobyl.