South Portland Ambient VOC Canister Sampling Results
Graphic Charts of Grab Sampling Canister Results
Please NOTE: The graphic charts visualizing the grouping of the aliphatic compound results now include our improved approach for summarizing and displaying this data.
Sampling locations displayed with an astrisk(*) represent ones that we have inferred, and are based on the address where the citizen lives, if they provided that information. This was done for samples where the sampling location information was missing on the chain of custody form that accompanied the return of the canister to the lab for analysis.
CAUTION to grab sampling data users: It is not appropriate to use grab sample data for any comparison to longer term average (e.g. annual) levels, guidelines or standards for health assessment purposes. DEP is working with staff from the Maine Center for Disease Control (CDC) to develop ways and visualizations of grab sampling data comparisons that are appropriate for their very short time durations, and are useful to the public in increasing their understanding of this data. Check back here soon to see what we've come up with on this topic.
For more information, contact Andy Johnson (207) 480-0906.
|8/11/2019||*Bug Light Park||ME09345|
Graphic Charts of 24-Hour Average Canister Results
|June & July 2019||SPAssessors Office||SPAssess_JuneJuly2019|
|August 2019||SPAssessors Office||SPAssess_Aug2019|
|August 2019||Bug Light||SPBugL_Aug2019|
Excel Spreadsheet of All Canister Numerical Data
Data collected by the project is available in an Excel spreadsheet file containing both the grab sampling and 24-hour average data.
Please NOTE: The October 22, 2019 update to this Excel file contains the addition of listing the units (parts per billion or ppb) that the data is reported in, and the deletion of the “Totals” column, which was inadvertently included, as well as other improvements resulting from our data handling and reporting process. The initial data file was created almost exclusively by manually entering all of the sample information and analytical results. We took this approach initially because it was the quickest method available to us for assembling and compiling the project’s data in time to present it at the August 20, 2019 City Council public workshop, followed by publicly posting it to this website several days later. We have since developed and implemented a completely electronic process for populating the spreadsheet with updated data and information, which will make future updates faster and more accurate by avoiding the occasional manual “typo” of a number, decimal point or compound name. The change in data handling methods between this file version and the initial one is the reason why users will note some very, very small differences in the previously reported concentrations and averages, and corrections to the spelling of some compound names.
The second change users will note is in how the aliphatic compounds data is presented. Previously, we were reporting the total sum of all aliphatic compounds detected. Because there are so many of them to review and validate, this was a time-consuming task that cannot be fully automated. Consequently, we have chosen to report and summarize a selective list of those aliphatic compounds that we believe play the most important role with respect to the broader VOC emission source categories we have already been able to identify are present in the City through sampling results to date. This change from previously reporting all detected aliphatic compounds to just the selected ones as now listed in this VOC category, is the reason why these results are different from those reported previously.