Artesian well: Artesian well, well from which water flows under natural pressure without pumping. It is dug or drilled wherever a gently dipping, permeable rock layer (such as sandstone)
It is known to be the worst air-pollution event in the history of the United Kingdom, and the most significant in terms of its effect on environmental research, government regulation, and public awareness of the relationship between air quality and health. Bell, Michelle L. and Davis, Devra Lee. 2  Reassessment of the Lethal London Fog of 1952: Novel Indicators of Acute and Chronic Consequences of Acute Exposure to Air Pollution ( Environmental Health Perspectives , June 2001).
Atmospheric Air contains approximately 21% oxygen (O2) by volume. The other 79% of other gases is mostly nitrogen (N2), so we will assume air to be composed of 21% oxygen and 79% nitrogen by volume. Thus each mole of oxygen needed to oxidize the hydrocarbon is accompanied by 79/21 = 3.76 moles of nitrogen. Using this combination the molecular mass of air becomes 29 [kg/kmol]. Note that it is assumed that the nitrogen will not normally undergo any chemical reaction.