Steering Committee, On last week's conference call, we discussed briefly the prospect of calculating some area sources at the regional level where it makes sense to do so from a standpoint of work efficiency and overall consistency. I mentioned that I would compile and send out a table summarizing what area source categories have been estimated by each state/province for the 2002 inventory to provide a better basis for further discussion. The table is attached here and a description of how it was compiled and some initial observations are below. The SCCs shown are all those that anyone has reported emissions for in 2002 using source type "A." This is a query of the 2002 repository that looked for activity records linked to "A" sources and returned the SCCs for the processes those activities belong to. I added to that a count of the number of sources within each state that had emissions from a process with the each SCC. This list therefore includes only a list of the Area Source SCCs that are actually being used, not all the potential Area Source SCCs, of which there are probably many more. I then went through and classified these 170+ SCCS into about 30 categories that I've called "GLC methodology category." This is intended to be at a similar level to the distinctions we've made in putting together the methodology documents in the past. My classification here is probably not perfect and some feedback could be used. I also added a column showing how many jurisdictions reported emissions for any of the SCCs within an given methodology classification. Looking at it that way helps minimize the focus on differences in which SCCs people are using and focus on whether certain types of sources are being estimated. I also added columns for what type of activity data is required and a column to indicate the feasibility of estimating a certain category at the regional level rather than state-by state. These last few columns aren't very complete at this point and input could be used there as well. Perhaps on the next call we can try to fill some of those fields in more fully. Some states are in the process of adding a few area sources as part of the b(a)p assessment and if that data hasn't yet reached the repository, it's not reflected in the attached table. It should also be pointed out that the table only presents information on whether or not certain SCCs are being reported by various states/provices and doesn't say anything about whether similar methodologies or emission factors are used. The table shows that there are 5 categories that all nine states/province have estimated and 6 more that 7-8 jurisdiction estimated. There are 7 that 3-5 estimated and 13 that 1-2 estimated. I would say that it's generally the case that those source types that many states are currently estimating are those that will be the best candidates for estimating at the regional level. Among the others, there may be a handful that are significant categories and easily estimated that we decide to do at the regional level also. We can assess each on its own merits in terms of whether it's worth the effort to inventory and whether inventorying it at the regional level makes sense. It should be clear at the outset of the discussion that if we do choose to do some of these calculations on a regional basis, we would do so with the understanding that: 1) each state and province always has control of it's own data and can change or omit data for a given source if they feel the regional method isn't suitable to them; and 2) when the calculations are done, each state would receive all the underlying data (activity data, emission factors, emissions, etc.) so that they would have complete ownership of the data within their own agency for future analysis or use. As a sidenote, Minnesota wins the award for best source category for their inclusion of human perspiration. Michigan runs a close second for their inclusion of beer fermentation as an area source. Is that home-brew that you're attempting to quantify, Dennis? ______________________ Jon Dettling Great Lakes Commission 734-971-9135 dettling@glc.org
Attachment:
Area_Sources.xls
Description: MS-Excel spreadsheet