Atmosphere is basically defined as a mixture of gases, water, dust, and other particulates held in place by gravity. Atmospheric pressure is how much air weighs if it were contained in a column extending from the Earth’s surface to space. Solar radiation is when electromagnetic waves from the sun bring energy in the form of heat to the Earth. Hydrology describes the science of the movement, distribution, and quality of water throughout the Earth. There are two main types of fog: radiation and advection fog. Radiation or cooling fog forms when still, moist air cools and heat is pulled from the air to the Earth and the air cools to the point that dew forms. Advection fog is created when moist air flows over a cool surface and creates a fog. Computerized dispersion models also have been developed to predict where and how far odor plumes from concentrated animal feeding operations can travel.