Navigation at Sea, History of. The first Western civilization known to have developed the art of navigation at sea were the Phoenicians, about 4,000 years ago (c. 2000 B.C.E. ). Phoenician sailors accomplished navigation by using primitive charts and observations of the Sun and stars to determine directions.
Air pollution risk is a function of the hazard of the pollutant and the exposure to that pollutant. Air pollution exposure can be expressed for an individual, for certain groups (e.g. neighborhoods or children living in a county), or for entire populations.ther examples include carbon monoxide gas from motor vehicle exhaust, or the sulfur dioxide released from factories. Secondary pollutants are not emitted directly. Rather, they form in the air when primary pollutants react or interact.
1 The earth's atmosphere contains trace gases, some of which absorb heat. 2  These gases (water vapor, carbon dioxide, methane, ozone, and nitrous oxide) are referred to as greenhouse gases.. 3  Albedo has an important influence on the earth's temperature.4  Greenhouses are structures designed to retain heat. These gases (water vapor, carbon dioxide, methane, ozone, and nitrous oxide) are referred to as greenhouse gases.. 2  Albedo has an important influence on the earth's temperature.