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IMPROVE Network Assessment Plans. IMPROVE Network Assessment. Motivation: EPA’s air quality monitoring budget is not growing, but their requirements are changing and expanding Thus far their support of IMPROVE particle speciation has not been affected
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IMPROVE Network Assessment • Motivation: • EPA’s air quality monitoring budget is not growing, but their requirements are changing and expanding • Thus far their support of IMPROVE particle speciation has not been affected • EPA’s level of support for IMPROVE will be reviewed next year
IMPROVE Network Assessment • Objectives: With respect to their utility for meeting federal visibility protection requirements • Identify monitoring sites whose data are essentially redundant to that of other sites • Identify likely spatial gaps in the network • Prioritize the IMPROVE & Protocol sites • Document the assessment in a report to EPA
IMPROVE Network Assessment • Tentative technical approach • Identify neighboring sites who’s primary particulate composition data have similar magnitudes and seasonal variations, and are highly correlated (compared to collocated samplers) • Assess current network’s coverage in regions where anticipated emission changes are likely to significantly alter current spatial concentration gradients (could use CAIR modeling) • Compare results with the original IMPROVE criteria for representative monitoring (horizontal distance < 100km, elevation within class I area range +100ft or +10%) • Evaluate budget consequences of network reconfigurations (cost to add or remove sites)
IMPROVE Network Assessment • Management approach options: • Have existing IMPROVE team perform the assessment (CIRA, UCD, one of the sponsoring agencies, or some combination) • Contract for the assessment • Related activities: • IMPROVE report being planned by CIRA • RPO’s are preparing a Regional Haze Monitoring Strategy document • WRAP tribal monitoring needs assessment • Other related activities?
There’s a natural tendency to want to group sites to simplify analysis. • Does that mean we only need one or two sites in a group? • Shown here are groupings by WRAP based on similar haze contributions by each state’s point and mobile sources using CMAQ modeling. • Others have done groupings of IMPROVE monitoring sites. • Is there value in using groupings to assess the IMPROVE network sites?
Are sites with different major component contributing to annual 20% worst haze days an indication that each site is necessary? • How similar do the contribution to haze data need to be? • How important are similar seasonal patterns for 20% worst haze days in assessing whether a pair of sites are redundant? • How similar would they need to be?
Correlation coefficients between paired composition data tend to decrease with distance between sites. • Even for sulfur that is pretty uniform over large regions, the correlation coefficient is less than 0.8 at ~100km spacing between sites. • Is r > 0.8 similar enough that one of the sites could be removed? • Is this a reasonable way to evaluate the IMPROVE network?