air pollution on the environment is a danger problem in the world. Bothe the sulfur and the nitrogen cycles are involved in urban and industrial air pollution that increasingly threatens the health of man and plants. The oxides of nitrogen (NO and NO₂) and sulfur (S₂) are rather toxic gases which are but transitory steps leading to the formation of nitrate (NO₃) and sulfate (SO₄) in their respective cycles. They are normally present in most environment in very low concentrations. The burning of fossil fuels however, has greatly increased the concentration of these volatile. oxides in the air, especially in environment urban regions, to the extent that they constitute about a third of the some 150 million tons of industrial air pollutants estimated to be released annually over the united states. Coal – burning electrical generating plants constitute a major source of SO₂, and the automobile is a major source of NO₂. Sulfur dioxide is very damaging to the photosynthetic process; the destruction of vegetation and crops around copper smelters and in the los Angeles basin is caused by this pollutant. Also, SO₂ combines with water vapor to produce airborne sulfuric acid (H₂ SO₄ ). The resulting ‘’acid rain’’ causes millions of dollars damage to metal, limestone, and other construction material, not to mention possible damage to respiratory tissues. Likensand Bormann (1974) have documented how the PH of rainwater falling over the industrialized area has decreased (that is rain has become more acid) during the past two decades.
 The oxides of nitrogen dangers for environment

        The oxides of nitrogen is very harmful problem for our environment and The oxides of nitrogen are particularly harmful to lungs and are thought to contribute to the increase in respiratory diseases  and cancer in urban populations. Furthermore, these oxides combine with hydrocarbons and other pollutants under the driving force of environment sunlight to produce a synergism (=total effect of the interaction exceeds the sum of the effects of each substance) called ‘’photochemical smog’’. Technology is available to reduce these air and environment pollutants at their sources but so far it has proved to be expensive. Air pollution may well limit the size of fuel – powered cities environment, at least for the next couple of decades and this could work out as a net benefit for man.