North Shore AIR

WHERE SHOULD WE START?

This report's goal was to achieve one overall priority ranking.   This proved more difficult than expected due to the varied nature of the list of chemicals and years that data is available from different agency data sources.  Since our Community Input for ranking focused on the properties of each chemical, rather than on quantity, the first goal was to determine what chemicals should be on our list to get prioritized.  We chose to include the HAPs quantified in the 1999 NATA that had already been identified by EPA as being the highest risk to see how our ranking may differ from EPA - this would include HAPs from mobile, area, and major sources.  In addition, we included all the chemicals where recent data was available at the community level.  These included Criteria pollutants, as well as specific HAPs, VOCs, and other air pollutants that were self-reported for 2003 from large point sources/Major sources in the target communities through either MADEP Air Source Registration, MA TURA, or EPA TRI, as well as smaller sources from drycleaning reported through MADEP ERP.  This ranking therefore takes mobile, area, and major sources into account, and does not separately rank Criteria pollutants from HAPs, but rather ranks them all against each other to form one combined ranking.

Each of the chemicals on the list was then researched, using www.Scorecard.org from Environmental Defense for their attributes related to our Top 10 community-ranked concerns.  The total of their weighted score was then added to give each chemical a rank.

The chart below includes the community-ranked score (largest score = highest concern) and also includes the quantities that could be determined.   The quantity data is only given as a reference point in comparing risk to quantity and to give some feel for how much reduction might be available or needed for a particular chemical.   There are many inconsistencies with the quantity data and thus they are not directly comparable since some of the data is from 1999 and some from 2003.  In addition, the quantity data assumes an equal distribution of County estimated emissions in the 1999 NATA data to determine the fraction of emissions in the census tracts of our three target communities. 

NOTE: The chemicals listed in all CAPS are from EPA's 1999 NATA High Risk listing, while the remaining chemicals are from the small group of facilities that self-reported through other reporting mechanisms in 2003.

Since these chemical specific numbers are based off the 2003 data from both TRI and MA DEP Air Source Reg the majority of the contribution of these chemicals in our 3 communities comes from the Salem Harbor Power Station.  Thus, this ranking provides targets for those specific chemicals that should be attempted to be reduced from that facility primarily.  However, it should be noted that N-Hexane, N, N – Dimethylformamide, Toluene, and Triethylamine are all contributed by Univar and thus reductions of these chemical emissions would need to target their operations.

Based on the above ranking - a further review was undertaken to understand what sources contributed to the emissions of each of the top 10 chemicals, and thus what reduction targets could be set in our target communities.

Based on this review of the data the following priorities for our target communities were identified using a combination of community and EPA risk ranking evaluation:

• Mobile Sources (on and off road) due to their contribution to 8 of the top 10 risk chemicals (Benzene-92%, Lead-64%, 1,3- Butadiene-97%, Carbon  Monoxide-89%, Nitrogen Oxides-61%, VOCs-46%, Acrolein-67%, Napthalene-31%.)
• Reductions of Fossil Fuel Use at Salem Power plant due to its contribution to 4 of the top 10 risk chemicals (Lead, Carbon Monoxide, Nitrogen Oxide, and Bis (2-Ethylhexyl) Phthlate.)
• Consumer products containing  3 of the top 10 risk chemicals (Carbon Tetrachloride , Tetrachloroethylene, and Naphthalene.)
• Drycleaners due to their contribution to 70% of the Tetrachloroethylene use.
• Gasoline Service Stations due to contributions to Benzene (largest risk chemical -although Gas Stations are small % of contribution) and Naphthalene.