CRC Report No. A-34 - Coordinating Research Council

April 2005
(b)
siteid Anaheim exp 1
Actual Contribution, Round 4, Experiment 1, Anaheim, average over all days
100%
SCE (%)
80%
60%
40%
20%
Data
Average of Other Sources
Average of Synthetic Ind Ops
Average of Biogenics
Average of Degreasing
Average of Coatings and Solvents
Average of Architectural Coatings
Average of Consumer Products
Average of Refinery Operations
Average of Oil and Gas Extraction
Average of Gasoline Marketing/Refueling
Average of Onroad Diesel
Average of Gasoline headspace
Average of Onroad Gasoline Exhaust
0%
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
HOUR
tim e
Figure 4-4. Comparison of detailed source contributions for experiment 1 in Round 4 at Anaheim
by hour of day: (a) CMB and (b) actual.
Findings from Hourly Analyses
• Focusing on morning (6-9 am) samples did not clearly improve the accuracy of CMB.
Correspondingly, focusing on afternoon samples (1-4 pm) did not clearly degrade the
performance of CMB, especially for samples in areas of high emissions density.
Problems for downwind samples are largely independent of the time of day.
• Reducing the number of samples at each receptor from 48 to 12 in order to restrict the
time-period of analysis did degrade CMB performance.
• CMB performance is more reliable for daily average source contributions than for
individual hours.
4.3 EXPERIMENTS 9-12: APPROACHING IDEAL CONDITIONS
Experiments 9-12 were designed after preliminary analysis of experiments 1-8 in Rounds 1 and
2. Experiments 9-12 were designed to investigate how chemical decay and sampling noise
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