City Heights CO and PM2.5 Data Analysis Report - Air Pollution ...

More documents

Recommendations

Info

Fine Particulate Matter (PM2.5)An additional concern of the City Heights community is the concentration of fine particulatematter of 2.5 microns and less in diameter (known as PM2.5). The District proposed tomeasure PM2.5 at two sites using two different sampling methods. The official method formeasuring PM2.5 is a filter-based system (the Federal Reference Method, or FRM). Thissystem measures PM2.5 concentrations over 24-hour periods, with the resulting data reportedin micrograms per cubic meter (µg/m3).Although this system is very accurate, the sample is an integrated sample, collected over theentire 24-hour period. Therefore, this measurement does not provide any information ondiurnal emission patterns. To address this issue, the District proposed using an instrumentknown as an EBAM. The EBAM measures hourly concentrations of PM2.5, providinginformation on diurnal patterns and concentrations.The District installed two EBAMs for this project. One EBAM was collocated with the FRMsampler at Central Elementary School. The second unit was located at Wilson MiddleSchool; a few blocks to the northwest (see Figure 1).The resulting data are then compared to the Federal 24-hour standard for PM2.5 (there is noseparate state standard for 24-hour periods (see Table 5). The 24-hour PM2.5 standard is metif the 98 th percentile of all samples is below the standard, averaged over three years.PM2.5 StandardsCalifornia StandardsFederal Standards24-Hour No separate State Standard 35 µg/m3Annual Arithmetic Mean 12 µg/m3 15.0 µg/m3Table 5.State and federal 24-hour and annual ambient air quality standards for PM2.5.This study relies heavily on the continuous data collected by the EBAM units to betterunderstand air quality conditions in City Heights. It is therefore important to know how theEBAM data compare to the official FRM data (the filter-based method).The daily FRM PM2.5 concentrations are plotted along with the EBAM-derived PM2.5concentrations in Figure 15. This graph shows that, overall, the two methods compared well.In general, the EBAM reported higher concentrations than the FRM, especially whenconcentrations were elevated to near or above the 24-hour standard.- 20 -
Central Elementary School: FRM vs. EBAMDecember 20, 2008, through January 29, 200960.050.0PM2.5 (µg/m3)40.030.020.0FRMEBAM24-Hr Standard10.00.0DateFigure 15.Graph showing the 24-hour PM2.5 concentrations collected by the FRM andthe EBAM at Central Elementary School from December 20, 2008, throughJanuary 29, 2009.The numerical values that generated Figure 15 are shown in Table 6 (the EBAM data forWilson Middle School are shown in Table 6 for comparison). The official, FRM data fromCentral Elementary exceeded the federal 24-hour standard on two days during the project.These exceedances occurred on January 1, and January 2, 2009 (42.4 µg/m3 and 38.1 µg/m3,respectively).- 21 -
Page 2 and 3: THIS PAGE INTENTIONALLY LEFT BLANK
Page 4 and 5: THIS PAGE INTENTIONALLY LEFT BLANK
Page 6: PROJECT DESCRIPTIONEarly in 2008, t
Page 11 and 12: Figure 3.Morning wind rose for mete
Page 13 and 14: Figure 5.Evening wind rose for mete
Page 15 and 16: Hourly CO Data for: Sunday, 1/18/20
Page 17 and 18: San Diego Hourly CO Data Averages b
Page 19 and 20: San Diego Hourly CO Data Averages b
Page 21 and 22: Hourly CO Data for: Thursday, 1/1/2
Page 23: TEP/CES CO Averages by Day of Week
Page 27 and 28: The District operates five BAM unit
Page 29 and 30: Central Elementary School and Wilso
Page 31 and 32: San Diego County FRM PM2.5 Data (In

City Heights CO and PM2.5 Data Analysis Report - Air Pollution ...

Create successful ePaper yourself

Delete template?

Save as template?