1. 6 City CSN/IMPROVE Comparison

2. IMPROVE/CSN Organic Carbon URG MASS – 16.7 LPM; IMPROVE ~22 LPM; Other STN 6-7 LPM IMPROVE OC un-adjusted for blank IMP = 0.861STN – 1.35; R2 0.93 IMP = 0.742STN – 0.437; R2 0.85 IMP = 0.758STN – 0.446; R2 0.94 IMP = 0.804STN – 0.283; R2 0.64 IMP = 1.09STN – 0.052; R2 0.97 IMP = 0.915STN – 0.08; R2 0.96 URG MetOne Andersen

3. CSN Blanks “Old” CSN Blanks – all sites –3% Trip Blanks –10% Field Blanks (momentarily exposed) Decreased to 5% May 2007 “New” CSN Blanks – all sites –3% Trip Blanks –10% Field Blanks –30% Backup Quartz (QBQ) –Field Blank collected on same day as QBQ