Orange County NC Website
3 r� <br /> TF coo <br /> op <br /> Environmental Quality Indicator : <br /> ` � ` ��� ' • � •L., - � '. � ..=. {�' , . ' 1 , .� � � �= � I. ...r .�� Nam.. f'� +� s:..a <br /> a'�' •\.,+' l �• ,''T :.+--' • ..P" ^� J 1 J J 1 1 .,. a:•1 R ...�. .1d � JJJ� ..y � ,1 ! tTr.u. <br /> Why indicator There are six pollutants for which National Ambient Air Quality Standards ( NAAQS ) have <br /> been established : carbon monoxide , ozone , sulfur dioxide, nitrogen dioxide, suspended <br /> Was Set ected particulate matter, and lead . In order to determine whether the NAAQS are being met in <br /> North Carolina , the NC Division of Air Quality ( NC DAQ) monitors air quality at stations <br /> located in air quality control regions throughout the state . Wake County is in the Eastern <br /> Piedmont Air Quality Control Region . <br /> In the past, the Raleigh - Durham area experienced carbon monoxide and ozone levels <br /> that exceeded the national standards . However, due to improved monitoring data, Wake <br /> County was redesignated as " maintenance" for carbon monoxide on September 18 , 19950 <br /> and " maintenance " for ozone on June 171 1994 . The county is currently meeting all the <br /> NAAQS . Of the six pollutants for which there are NAAQS , carbon monoxide and ozone <br /> are the most widespread and abundant in the region , and also statewide . <br /> How indicator Carbon monoxide is a colorless, poisonous gas produced by incomplete combustion of <br /> fuel . Vehicular emissions account for the majority of the carbon monoxide in the region . <br /> Was n1ea5Ur8d The NAAQS for carbon monoxide is 9 parts per million ( ppm ) for an 8 - hour average <br /> period and 35 ppm for a 1 - hour average period . <br /> Ozone is made up of three oxygen atoms , and is the main component of smog . Ozone is <br /> mainly formed by a series of complex reactions involving hydro- carbons , nitrogen oxides <br /> and sunlight . The NAAQS for ozone is 0 . 122 ppm for a 1 - hour average . <br /> In 1995 , the NC DAQ maintained four stations in Wake County monitoring carbon <br /> monoxide and three stations monitoring ozone . One station in Franklin County monitors <br /> ozone concentrations downwind of Wake County. <br /> The trend Since 1979 , carbon monoxide concentrations in Raleigh , Wake County, and the <br /> region have been generally decreasing . Figure A shows the 8 - hour average carbon <br /> in Wake County monoxide concentrations occurring between 1990. 1995 at two monitoring stations <br /> in Wake County. Since 1990 , average ozone concentrations have been generally <br /> decreasing , but can be affected by weather conditions . For example , during the hot , di <br /> summer of 1988 , the ozone standard was exceeded 69 times . During the cool , wet <br /> summer of 1989 , the standard was exceeded only 6 times . <br /> The Wake County Vehicles are the major source of carbon monoxide and ozone in Wake County. In 1983 . <br /> there were an estimated 250 , 000 vehicles registered in the County. By 1995 , the numbE <br /> Governmen t reovon5e had risen to 436 , 439 vehicles . According to the NC DAQ , programs to control vehicula <br /> emissions and to maintain traffic flow have helped reduce air pollution problems in Wa <br /> County. These programs include the Environmental Protection Agency 's vehicular <br /> emissions standards , the Wake County Inspection and Maintenance Program , and <br /> computerized signal timing systems in Raleigh . <br /> 17 <br />