Sulfur and Nitrogen Dioxide

What exactly are sulfur and nitrogen dioxides?  Well, they are each linked to one of the six criteria air pollutants, those being nitrogen oxides and sulfur oxides and neither are good for one's health.  So you may be wondering, where do these nitrogen and sulfur dioxides come from?  Well, according to the site http://www.epa.gov/airquality/sulfurdioxide/ , the major source of sulfur dioxides is a result of big industries burning fossil fuels as well as the burning of fuel that contains sulfur.  This is also where you find most of the sources of nitrogen dioxides.  These sources include motor vehicles and power plants.  This information was also found on the same site that is linked above.  So obviously if these pollutants are watched carefully by the EPA they must not be good for one's health.  According to the site http://www.atsdr.cdc.gov/phs/phs.asp?id=251&tid=46 , sulfur dioxide has very negative health effects from a long term exposure and even short term exposures, especially if the exposure time is in an area where the level of sulfur dioxide is high.  These health effects include airway obstructions and it also effects different functions of the lungs and can cause a burning to the throat and also the nose and respiratory problems and irritations.  The health effects of nitrogen dioxides are very similar to those caused by sulfur dioxides.  According to the site http://www.epa.gov/airquality/nitrogenoxides/health.html , they are respiratory problems, as well as loss in functions of the lungs.  Also, airways may be inflamed due to exposure.  Respiratory problems from both these pollutants are a wide variety of things.  Sulfur dioxides and nitrogen dioxides have similar effects on the respiratory tract when exposed, however, their effects are also slightly different.  According to the site http://www.atsdr.cdc.gov/mmg/mmg.asp?id=249&tid=46 , the exposure to sulfur dioxides reacts with substances in the upper airway which then causes the lower airway, or the bronchioles, to constrict.  So you could say that both the upper and lower tract of the respiratory tract are effected by sulfur dioxides.  According to the site http://www.atsdr.cdc.gov/mmg/mmg.asp?id=394&tid=69 , the lower respiratory tract is the main area that is affected when exposed to nitrogen dioxide, as opposed to sulfur dioxide that has an effect on both tracts.  Sulfur dioxide effects both while nitrogen dioxide really effects the lower tract.  To learn more in detail about the upper respiratory tract and lower respiratory tract, go to this site: http://www.webmd.com/lung/respiratory-system-18881 .  So what kind of effect do these pollutants have on plants, say, lichens?  Well, both actually have a negative effect on the lichen population, according to the site http://staff.concord.org/~btinker/gaiamatters/investigations/lichens/affectslichens.html .  This site describes that sulfur dioxides have a lot of responsibility in the decrease in the lichen population compared to nitrogen dioxides.  Yes, nitrogen dioxides are harmful to lichen as well, but sulfur dioxides are the main cause for loss in lichen species.  They say that lichen will either be destroyed by the pollution or a different type of lichen more tolerant to the pollution will start to grow instead.  I hope this article was helpful describing some information about the health effects of sulfur and nitrogen dioxides as well as where those pollutants come from and how they can be harmful to the plants that are exposed to them as well.