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manner by shielding earth from harmful ultraviolet radiation emitted by the sun. However,03 in the lower
<br /> atmosphere(troposphere)is a major health and environmental concern. Because sunlight and heat serve as
<br /> ` catalysts for the reactions between 03 precursors, 03 concentrations typically peak during summer in the Northern
<br /> Hemisphere(EPA 2002). In general,03 concentrations reflect an interplay of emissions of 03 precursors,
<br /> transport meteorology,and atmospheric chemistry(Godish 1991).
<br /> The adverse health effects associated with 03 pertain to the respiratory system. 03 not only affects sensitive receptors,
<br /> such as asthmatics and children,but healthy adults as well. Exposure to ambient levels of 03 ranging from 0.10 to 0.40
<br /> parts per million(ppm)for 1 to 2 hours significantly alters lung function. Ambient levels of 03 above 0.12 ppm are
<br /> linked to symptomatic responses that include throat dryness,chest tightness,shortness of breath,headache,and nausea.
<br /> In addition,evidence exists relating 03 exposure to an increase in the permeability of respiratory epithelia,leading to an
<br /> increase in responsiveness of the respiratory system to bronchoconstrictive challenges,and the interference or
<br /> inhibition of the immune system's ability to defend against infection(Godish 1991).
<br /> Carbon Monoxide
<br /> CO is a colorless,odorless,poisonous gas produced by incomplete burning of carbon in fuels,principally from
<br /> mobile(transportation) sources of pollution. In fact, 78%of the nationwide CO emissions are from mobile
<br /> (transportation) sources. The other 22%consists of CO emissions from forest fires,wood-burning stoves,
<br /> incinerators,and industrial sources. Peak CO levels are localized near areas with high concentrations of mobile
<br /> (transportation)sources and occur typically during winter when cahn conditions are common.
<br /> ~ CO enters the bloodstream through the lungs by combining with hemoglobin,which normally supplies oxygen to
<br /> the cells. However,CO combines with hemoglobin much more readily than oxygen does,resulting in a drastic
<br /> reduction in the amount of oxygen available to the cells. Adverse health effects associated with exposure to CO
<br /> concentrations include such symptoms as dizziness,headaches, slow reflexes,and fatigue. CO exposure is
<br /> especially harmful to individuals who suffer from cardiovascular and respiratory diseases(EPA 2002).
<br /> Nitrogen Dioxide
<br /> NO2 is a brownish,reactive gas that is present in all urban environments. The major artificial sources ofNO2 are
<br /> combustion devices that emit nitric oxide(NO);NO reacts in the atmosphere to form NO2(EPA 2002). The combined
<br /> emissions of NO and NO2 are referred to as oxides of nitrogen(NW,which are reported as equivalent NO2.
<br /> Inhalation is the most common route of exposure to NO2,with the severity of related adverse health effects
<br /> dependent primarily on the concentration inhaled rather than the duration of exposure. An individual may
<br /> experience a variety of acute symptoms,including coughing,difficulty breathing,vomiting,headache,and eye
<br /> irritation during or shortly after exposure. After approximately 4 to 12 hours,an exposed individual may
<br /> experience chemical pneumonitis or pulmonary edema with breathing abnormalities,cough,hemoptysis,
<br /> cyanosis,chest pain,and rapid heartbeat. Severe, symptomatic NO2 intoxication after acute exposure has on
<br /> occasion been linked to prolonged respiratory impairment,and includes such symptoms as chronic bronchitis and
<br /> + decreased lung functions.
<br /> Sulfur Dioxide
<br /> M
<br /> SO2 is produced by such stationary sources as coal and oil combustion,steel mills,refineries,pulp and paper mills,
<br /> and nonferrous smelters. The major adverse health effects associated with SO2 exposure pertain to the upper
<br /> respiratory tract. SO2 is a respiratory irritant with bronchoconstriction occurring with inhalation of SO2 at 5 ppm or
<br /> more. On contact with the moist mucous membranes,SO2 produces sulfurous acid,which is a direct irritant.
<br /> Concentration rather than duration of the exposure is an important determinant of respiratory effects. Exposure to
<br /> high concentrations of sulfur dioxide may result in edema of the lungs or glottis and respiratory paralysis.
<br /> College Park at Mountain House Specffic Plan III Draft EIR EDAW
<br /> San Joaquin County 4.12-3 Air Quality
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