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I I I I I I I I I I I I I I I I I I I - - ---- ------- - . _"- . _' _, __ .._. o. -:'--..;..._ ,._ ~__. _ _._ _... __ '!he followin3' CD analysis enploys stamard, cx:rrprt:erized procedures which result in an estimate of carlx>n m::naxide c:c:n::entratians for future years. '!he analysis is based on many '''worst casefl assurrptions. '!his, cc::xnbined with the inherent oonsezvative nature of the m:dels, produces results which may be considered the highest c:c:n::entratians tbat may reasonably be expected. Ifethc:Idology In order to estmate the effect of the project on the quality of the atmosphere, Environmental Protection Agency procedures were used as described in its publication, Guidelines For Air OUality Maintenance Plann.i.n::f ani Anal vsis Volume 9 (Revised): Evaluatim Irxiirect Sources (U.S. Environmental Protection J!qercj. Office of Air, Noise, ani Radiation, Office of Air Quality Planni.rKJ am. st:arrlirds,' Research Triargle Park, North Carolina. EPA-450j4-78-o0l. September 1978. (OAQPS No. 1.2-028 R)). '!his is a starrlard manual for air quality analysis, accepte:l by both state am federal regulatory agen::ies. eaman DDtlOXide (CD) c:c:n::entrations are the erxi result of a p:t'OC)E!SS outlined belC1W. 1. Traffic volume estimate: HaJrly tum.inJ m:wement voltnnes are estimated for each intersection am. roadway ~nt. Volunes are estimated for the peak hour as well as the average boor of the peak consecutive eight hours. At signalized intersections, a capacity analysis is perfonood to determine the optim.Im t.iJniIgs at the signals. '!he capacity analysis is based on the methOOs of the 1985 Highway Capacity Manual (Institute of Transportation Erqineers, 1985). 2. Emission rate ca1a.1lation: For eadl intersection or road segment, an emission rate is cala1lated fran a base emission rate an:l correction factors iran the MJBIIE 3 m:rlel. 'lhese calculations are contained in a cx:rrprt:er program, roERP. 3. Dispersion m:x:ielirg: For each line segment or queue, the emission rate calculated in step 2 is used to calculate a resulti.rg concentration at the receptor. 'Ihe contrihztion of each line &egne1t is added. to obtain the c:c:n::entration at the receptor. !his value, cambined with the backgroon:i c:c:n::entration, gives the total c:c:n::entration. Input Pammeters 1. Analysis Year 'Ihe year of the analysis will be 1995, whidl is the year after project cc:rrpletion am. when the deve1cpnent is anticipated to be at 90% occupE11'q . 2. Vehicle <baracteristics Vehicle Mix: '!he mix of vehicles used for this study is representative of the national average mix of vehicles. '!his is used since it would represent a 'tIIOrst case for the study area. 'Ihe vehicle mix is shown belO\ll. 11