75A - PH 1901 East First St - Laserfiche WebLink

Home Browse Search

Mitigated 51.6 27.4 31.6 0.1 4.7 2.0 SCAQMD Thresholds 75 100 550 150 150 ? 55 Peak daily construction activity emissions are estimated be below SCAQMD CEQA thresholds without the need for added mitigation. The only model -based mitigation measured applied for this project was watering exposed dirt surfaces at least three times per day as required per SCAQMD Rule 403 (Fugitive Dust), to minimize the generation of fugitive dust. LOCALIZED SIGNIFICANCE THRESHOLDS The SCAQMD has developed analysis parameters to evaluate ambient air quality on a local level in addition to the more regional emissions -based thresholds of significance. These analysis elements are called Localized Significance Thresholds (LSTs). LSTs were developed in response to Governing Board's Environmental Justice Enhancement Initiative 1 -4 and the LST methodology was provisionally adopted in October 2003 and formally approved by SCAQMD's Mobile Source Committee in February 2005. Use of an LST analysis for a project is optional, For the proposed project, the primary source of possible LST impact would be during construction, LSTs are applicable for a sensitive receptor where it is possible that an individual could remain for 24 hours such as a residence, hospital or convalescent facility. LST screening tables are available for 25, 50, 100, 200 and 500 meter source - receptor distances. For this project the nearest sensitive use would be the residences southeast of the project site at approximately 1200 feet from the closest site perimeter along Moir Court, and therefore, as a conservative approach, the receptor distance of 200 meters was selected for analysis. LSTs are only applicable to the following criteria pollutants; oxides of nitrogen (NOx), carbon monoxide (CO), and particulate matter (PM -10 and PM -2.5). LSTs represent the maximum emissions from a project that are not expected to cause or contribute to an exceedance of the most stringent applicable federal or state ambient air quality standard, and are developed based on the ambient concentrations of that pollutant for each source receptor area and distance to the nearest sensitive receptor, The SCAQMD has issued guidance on applying CaIEEMod to LSTs. LST pollutant screening level concentration data is currently published for 1, 2 and 5 acre sites for varying distances. Since CalEEMod calculates construction emissions based on the number of equipment hours and the maximum daily soil disturbance activity possible for each piece of equipment, the following tables should be used to determine the maximum daily disturbed - acreage for comparison to LSTs. Maximum Daily Disturbed Acreage );qni anent T pe ____Acres /S -hr -da Tractor 0.5 Graders 0,5 1W1 a W SL Ap • �- 75A -127