South Portland/Portland VOC Canister Sampling 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.

Of the 72 total grab sample canisters made available for this phase, 56 had valid results, 13 did not and 3 canisters (ME09254, ME09357, ME09358) were not returned. The valid samples are listed in the table to the right. Click on the "Sample ID" for any date / location to see the graphic visualization of the results. The 13 invalid samples were due to the following reasons:

• Citizens reported that three canisters (ME09226, ME09217, ME09388) did not have available vacuum to collect a sample. Most likely, these canisters leaked during shipment.
• Three other canisters (ME09323, ME09305, ME09322) did not collect an adequate amount of sample air needed for the laboratory's analytical system to run a valid analysis.
• The remaining six canisters (ME09229, ME09231, ME09232, ME09233, ME09234, ME09235) are void due to laboratory error. The canisters were not pumped down before shipment to South Portland therefore it was not possible to collect a valid sample of ambient air.
• The last sample (ME09421) was returned to the laboratory past it's valid holding time and was therefore not analyzed.

Many canisters were returned without noting the location (street name) where the sample was taken. Maine DEP has reviewed the chain of custody tags and has been able to determine the location for most. Please contact us if this information is not correct or if you have more information to add.

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. Staff from the Maine Center for Disease Control (CDC) gave a presentation to the South Portland City Council on November 26, 2019 that describes and illustrates their approach to interpreting this data from a health perspective. The grab sample data charts we’ve created here are intended to simply be a visualization of each sample’s results from an air quality perspective, comparing them to the 2018 annual averages from our Portland Deering Oaks site, which for this purpose are being used as reference or background concentrations for the area.

For more information, contact Danielle Twomey (207) 592-3951.