South Portland/Portland VOC Air Quality Monitoring Project

At the request of South Portland City officials, DEP staff attended an April 16, 2019 City Council public workshop focused on citizen concerns about odors and air emissions coming from petroleum product storage facilities in the city. One topic that was repeatedly expressed by the residents who spoke, was the very strong desire for air quality monitoring to be conducted within the City's boundaries, since none had been done since the early 2000s. DEP made a commitment at the workshop that it would work with the City to accomplish that goal. On August 28, 2019, officials from the City of Portland formally communicated identical air quality concerns of their citizens about the same VOC sources in South Portland. Since then, Air Bureau staff have collaborated with officials from both cities and other local partners to plan an ambient air quality monitoring project, where the monitoring objective is to collect data that will help answer the question "Is the air safe to breathe?"

The initial focus of the monitoring project is to measure Volatile Organic Compounds (VOCs), since they constitute a large majority of the compounds associated with the types of odors being reported, as well as air emissions that come from the facilities of concern. VOCs were also chosen because making that type of measurement is something that the Air Bureau air monitoring program is already set-up to do (and is doing) and capable of supporting.

Phases 1 & 2

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Licensed VOC Sources and 24-hour Sampling Site Locations
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In calendar year 2019, the project consisted of two phases: 1) an early "grab sampling" effort in South Portland, and 2) a network of eight fixed 24-hour sampling sites (five in South Portland and three in Portland). The grab sampling phase was launched on June 10 and concluded on September 15. As of November 1, all planned 24-hour sampling sites were established and are currently taking samples on a frequency of every-6-days. The sites in South Portland were placed so that each of the five districts had a site at a municipally owned/operated facility.

Phase 3

During calendar year 2020, the implementation of phase 3 began, which includes the addition of a meteorological (met.) monitoring system at each of the fixed 24-hour sampling sites, as well as the deployment of a portable sampling platform (PSP). The process of the met. system installations is still in progress, with the first two sites coming online in June, at the South Portland Assessors Office and the Portland Deering Oaks sites. The PSP will initially have both a canister sampling system for measuring VOCs (identical to ones used at the fixed 24-hour sampling sites), and a tube sampling system for measuring Polycyclic Aromatic Hydrocarbons (PAHs). It will eventually also include a met. monitoring system, as well as a continuous particulate matter monitoring system. Since the PSP can easily be moved from one location to another, it will allow 24-hour samples to be taken at a variety of additional places. This PSP data will help improve the overall spatial and temporal understanding of air quality in the project area. The first deployment of the PSP took place at the end of August.

As the first full year of concurrent 24-hour sampling by all of the VOC sites in the Project’s monitoring network approaches, DEP has informed officials in both cities that it intends to extend its support of the Project’s monitoring activities through 2021. DEP had committed to run these sites for one full year from the network completion date, that is, until November 2020. After a review of the first full years’ worth of data is completed by the Maine CDC, DEP and the Project’s partners, any recommendations for adjustments to the Project’s monitoring activities will be considered and implemented as resources allow.

Phase 4

Maine DEP agreed that, after at least a year of data had been collected in the South Portland – Portland VOC network the location of sites would be reevaluated. South Portland has proposed some changes. Maine DEP and the City remain in discussions at this time. The site list below will be updated as new sites begin to measure VOCs and more information will be provided here when all new sites for Phase 4 have been agreed upon.

24-hour sampling site locations and status

Phase 2 - Continued Operation

Phase 3

Phase 4

Phase 5

Site operated by the city of South Portland

  • South Portland: Pearl Street (first sample 10/27/2023)
  • South Portland: Front Street (coming early 2024)

Discontinued Sites

DEP Presentation given at City Council at August 20, 2019 meeting.

DEP Presentation given at City Council at November 26, 2019 meeting.

Legislative Briefing: Emissions from Bulk Petroleum Storage Facilities.

Canister sampling results