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e Y <br /> Mr. Dan Johnson <br /> December 30, 2008 <br /> Page 2 <br /> At higher concentrations, methane is flammable. However,the presence of methane gas in site soil <br /> does not mean there is an immediate threat of explosion because flames cannot typically propagate <br /> through soil. <br /> SURFACE EMISSIONS MONITORING <br /> On November 18, 2008, surface emissions monitoring was performed over the surface of the <br /> subject site. The intent of the monitoring was to identify any specific locations or areas of the <br /> landfill surface with organic compound concentrations exceeding SJVAPCD Rule 4642 threshold <br /> limit value of 1,000 ppmv measured as methane. <br /> EMISSIONS TESTING INSTRUMENTATION/CALIBRATION <br /> Instruments used to perform the landfill surface emission testing consisted of the following: <br /> • Landtec SEM-500 portable Flame Ionization Detector(FID). This instrument measures <br /> methane in air over a range of 1 to 50,000 ppmv. The SEM-500 meets SJVAPCD <br /> requirements and was calibrated in accordance with Rule 4642 Section 6.1.1.1 test methods. <br /> Instrument calibration logs are shown in Attachment 1. <br /> SURFACE EMISSIONS MONITORING PROCEDURES <br /> Surface emissions monitoring was conducted in accordance with SJVAPCD Rule 4642 Section <br /> 6.1.1.2. Monitoring was performed with the SEM-500 inlet held within 3 inches of the landfill <br /> surface while a technician walked a grid in parallel paths not more than 90 feet apart over the <br /> surface of the landfill. Cracks,holes and other breaks in the surface were also tested. Surface <br /> emissions readings were monitored approximately every 30 seconds and recorded if they exceed <br /> 1,000 ppmv. <br /> Recorded wind speed results are shown in Attachment 2. Wind speed averages were observed to <br /> remain below 10 miles per hour and no instantaneous speeds exceeded 15 miles per hour. No <br /> rainfall had occurred within 72 hours of the monitoring events. Therefore, site meteorological <br /> conditions were within the modified Rule 4642 requirements on the test date. <br /> TESTING RESULTS <br /> Landfill surface emissions monitoring showed no exceedence of Rule 4642 threshold limit of 1,000 <br /> ppmv. The highest reading detected was 15 ppmv, which is well below the 1,000 ppmv <br /> limit. Results of monitoring are shown on Figure 1 in Attachment 2. Based on these results, no <br /> additional testing is recommended at this time. <br />