2001 Quality Assurance Report
Gaseous Monitoring Network The APCD routinely monitors four gaseous pollutants: carbon monoxide (CO), ozone (O3), sulfur dioxide (SO2), and oxides of nitrogen (NOx). Fifty-eight accuracy audits were conducted in 2001. All but three of these audits were within the 10% full-scale analyzer response error considered acceptable by the APCD.
EPA interlaboratory comparisons were conducted during 2001 for carbon monoxide, ozone, sulfur dioxide, and nitrogen dioxide. The ozone comparisons were invalidated due to faulty NPAP equipment. Interlab comparisons are included for 18 gaseous analyzers. All interlab results were within the acceptable EPA performance criterion of 15% error, except one. It was determined that the instrument in question was in need of repair and recalibration.
Overall data recovery for the gaseous monitoring network was 92% in 2001. During this time only one of the analyzers in the APCD network failed to meet the EPA 75% data completeness criterion.
Particulate Monitoring Network
The APCD routinely monitors three size classes of particulate matter: total suspended particulate (TSP), inhalable particulate matter (PM10), and respirable particulate matter (PM2.5). Ambient lead concentrations are determined from analysis of TSP filters collected at selected sites. Field audits were performed at least semi-annually at all particulate monitoring sites in Colorado. A total of 606 particulate audits were conducted in 2001. Ninety-four percent of these audits passed both accuracy and design flow criteria. Only two audits during 2001 failed to meet the EPA accuracy criterium.
Ninety-two PM10 samplers and one TSP sampler were audited under the EPA NPAP interlaboratory program in 2001. All but 2 of these interlaboratory audits showed flow errors within EPA.s acceptable criteria. Four PM2.5 sites were audited under the EPA FRM PEP audit program to determine network bias. The bias of the PM2.5 network was determined to be (+)12.1% in 2001.
Overall APCD particulate network data recovery in 2001 was 93% for TSP, 85% for lead, 88% for PM10, and 93% for PM2.5.
Meteorological Monitoring Network
Audits of the meteorological monitoring network were conducted at 13 of the 19 meteorological sites during 2001.