DeforestationClearing Earth's forests on a massive scale, often resulting in damage to the quality of the land.
DioxinsFamily of 75 different toxic chlorinated hydrocarbon compounds formed as by-product in chemical reactions involving chlorine and hydrocarbons, usually at high temperatures. They are regarded as highly toxic compounds that are environmental pollutants and persistent organic pollutants (POPs).
DispersionThe movement of pollutants in the atmosphere is caused by transport, dispersion, and deposition. Dispersion results from local turbulence, that is, motions that last less than the time used to average the transport.
Dobson unitIt is the unit of measure for total ozone. If you were to take all the ozone in a column of air stretching from the surface of the earth to space, and bring all that ozone to standard temperature (0 °Celsius) and pressure (1013.25 millibars, or one atmosphere, or “atm”), the column would be about 0.3 centimeters thick. Thus, the total ozone would be 0.3 atm-cm. To make the units easier to work with, the “Dobson Unit” is defined to be 0.001 atm-cm. Our 0.3 atm-cm would be 300 DU.
DoseThe amount of a potentially harmful substance an individual ingests, inhales or absorbs through the skin.
DroughtDrought is an extended period when a region receives a deficiency in its water supply, whether atmospheric, surface or ground water. A drought can last for months or years. This condition occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region. Although droughts can persist for several years, even a short, intense drought can cause significant damage and harm to the local economy.
DustConsists of particles in the atmosphere that come from various sources such as soil, dust lifted by weather (an aeolian process), volcanic eruptions, and pollution. Atmospheric or wind-borne dust, also known as aeolian dust, comes from arid and dry regions where high velocity winds are able to remove mostly silt-sized material, deflating susceptible surfaces. Ex: plant pollen, human and animal hairs, textile fibers, paper fibers etc.