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5. Environmental Analysis <br />AIR QUALITY <br />Table 5.1-6 <br />Constructi Phase Regional Emissions <br />- (ire pounds Per ) <br />Construction Phase' <br />voc <br />NOx <br />co <br />SC <br />P 10 <br />P�V1 <br />Demolition <br />1 <br />8 <br />6 <br />0 <br />12 <br />1 <br />Construction <br />2 <br />12 <br />8 <br /><1 <br />1 <br />1 <br />Paving <br />2 <br />13 <br />9 <br />0 <br />1 <br />No <br />SCAOMD Standard <br />75 <br />100 <br />550 <br />150 <br />150 <br />M 55 <br />Significant? <br />No <br />No <br />No <br />No <br />No <br />No <br />Source. URBEMIS2007, Version 9.2.4 <br />' Construction equipment mix based on the URBEMIS2007 model defaults for a one -acre project site assuming six weeks of demolition, construction <br />and paging activit$es at each intersection, No grading activities are assumed as all work would occur in the existing right -of -war. <br />IMPACT 5.1-2.- PROJECT- RELATED SHORT-TERM CONSTRUCTION EMISSIONS WOULD NOT <br />EXPOSE SENSITIVE RECEPTORS TO SUBSTANTIAL POLLUTANT <br />CONCENTRATIONS. [THRESHOLD A -4] <br />Impact Ana"i : Unlike the mass (weight) of construction emissions shown in Table 5.1 -6 (described as <br />pounds per day), localized concentrations refer to an amount of a polIutarnt in a volume of air ppm orpg r <br />and can be correlated to potential health effects, Air quality analysis is based on the OA C S, which are the <br />most stringent AA QS established to provide a margin of safety in the protection of the public health and <br />welfare. They are designed to protect those sensitive receptors most susceptible to further respiratory <br />distress, such as asthmatics, the elderly, very young children, people already weakened by other disease or <br />illness, and persons engaged in strenuous work or exerci e. LSTs are applicable only to NO2, CO, Phi, ,,, and <br />PI 2,,. Because pollutants emitted during construction greatly depend on the proximity of the source to the <br />receptor, LSTs are based on the location of the emission source relative to the sensitive receptors as well as <br />on the quantity of emission. Table 5.1-7 shows construction emission rates and LSTs for SRA 17 based on <br />sensitive receptors a# a distance of meters feet), in accordance with the SOAQMD methodology. As <br />shown in this table, air pollutant emissions would not exceed the SCAQMD's LSTs for a one-acre site. <br />Consequently, construction emissions generated by the project would not expose sensitive receptors to <br />substantial pollutant concentrations and impacts would be less than significant. <br />Table 5.1-7 <br />Maximum Daily Construction Emissions ra re with the LST <br />Construcfion Phasel <br />Poll #cot ib d <br />N x <br />co <br />P 10 <br />P .s <br />Demolition <br />8 <br />6 <br />1 <br />1 <br />Construction <br />12 <br />3 <br />1 <br />1 <br />Paving <br />13 <br />9 <br />1 <br />1 <br />AM Standard <br />139 <br />440 <br />4 <br />3 <br />Significant? <br />No <br />No <br />No <br />No <br />Source: URBEMIS2007, Version 9.2.4 <br />Construction equipment crux based on the URBEMIS2007 model defaults for a one -acre project site assuming six weeks of demolition, <br />construction and paving activities at each intersection. No grading activities are assumed as all work would occur in the existing right -of- U. <br />FalrbavenlLincoln and Santa ClaralLincoln intersection Modificationj City of Santa Ana a Page 5-1- 7 <br />Supplement to the Santa Ana Second Main Track Project EIR Resolution No. 2009 -034 <br />Page 63 of 130 <br />