Water is a chemical substance with the chemical formula H 2 O. A water mol molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state (water vapor or steam). Water also exists in a liquid crystal state near hydr ophilic surfaces. Under nomenclature used to name chemical compounds, Dihydrogen monoxide is the scientific name for water, though it is almost never used. Water covers 70.9% of the Earth's surface, and is vital for all known forms of life. On Earth, 96.5% of the planet's water is found in oceans, 1.7% in groundwater, 1.7% in glaciers and the ice caps of Antarctica and Greenland, a small fraction in other large water bodies, and 0.001% in the air as vapor, clouds (formed of solid and liquid water particles suspended in air), and precipitation. Only 2.5% of the Earth's water is freshwater, and 98.8% of that water i s in ...

(Particulate Matter) Particulates – also known as particulate matter ( PM ), suspended particulate matter ( SPM ), fine particles , and soot – are tiny subdivisions of solid matter suspended in a gas or liquid. In contrast, aerosol refers to particles and/or liquid droplets and the gas together. Sources of particulate matter can be man made or natural. Air pollution and water pollution can take the form of solid particulate matter, or be dissolved . Salt is an example of a dissolved contaminant in water, while sand is generally a solid particulate. To improve water quality, solid particulates can be removed by water filters or settling and is referred to as insoluble particulate matter. Dissolved contaminants in water are often collected by distilling, allowing the water to evaporate and the contaminants to return to particle form and precipitate. Some particulates occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living veget...