Polygons in the 2010 Environmental Justice (EJ) Populations layer represent areas across the state with high minority, non-English speaking, and/or low-income populations. Data in this layer were compiled for Census 2010 block groups from the 2010 census redistricting tables and from the American Community Survey (ACS) 2006-2010 5 year estimates tables.

The 2010 EJ dataset should be used at the block group (BG) level to ensure that environmental planning and decision-making is done at the appropriate geographic scale. A fact sheet for 2010 EJ, EJ 2010 CommunitiesStatistics.pdf, lists municipalities with EJ BGs and statistics for each of these communities: the number of EJ BGs, the EJ criteria, the percentages of the BGs classified as EJ and the population living in these EJ BGs, and the mean EJ criteria count, which provides an indication of the diversity of the municipality’s EJ population and the intensity of EJ criteria found in the community.

The layer was produced by identifying polygons from the Census 2010 Block Groups layer. Blockgroup boundaries are based on population numbers rather than geographic size, and so blockgroups can vary greatly in size: from 3.5 acres in densely populated urban areas to nearly 19,000 acres in the western part of the state, with an average of 194 acres. Although the total population counts within blockgroups in the EJ dataset range from 82 to 4536, the population of 96% of block groups falls between 500 and 2500 people.

Blockgroups were identified as EJ using the following three criteria:

1. Percent Minority Population

From the Census 2010 redistricting tables (PL-94-171) tables: Table P2: Hispanic or Latino, and not Hispanic or Latino by race

• Non-minority = not Hispanic, white alone (P002005)

• Total population (P002001)

% minority = [ (P002001 – P002005) / P002001 ] } * 100

==> Any Block Group with a %Minority >= %25 was selected as an EJ population.

2. Income

From ACS 2006-2010 estimates tables: Table B19013 Median household income in the past 12 months (in 2010 inflation-adjusted dollars).

• The 2010 Massachusetts state median income used is $62,133, released by the USDA Economic Research Service

• 65.49% of this value is $ 40,673.

==> Any Block Group with a median household income in 2010 (B19013) less than or equal to this value was selected as an EJ population.

3. English Language Isolation

Linguistic isolation was used as an indicator of limited English language . A household in which no person 14 years old and over speaks only English and no person 14 years old and over who speaks a language other than English speaks English ‘‘Very well’’ is classified as ‘‘linguistically isolated.’’ In other words, a household in which all members 14 years old and over speak a non-English language and also speak English less than ‘‘Very well’’ (have difficulty with English) is ‘‘linguistically isolated.’’ All the members of a linguistically isolated household are tabulated as linguistically isolated, including members under 14 years old who may speak only English.

From the ACS 2006-2010 estimates tables: Table 16002 Household language by linguistic isolation: Household language by households in which no one 14 and over speaks English only or speaks a language other than English at home and speaks English "very welL"

These columns were used in this calculation (the columns in this ACS table do not have unique column IDs; column names in brackets are explanatory only):

• Total [number of households]

• Spanish: No one 14 and over speaks English only or speaks English "very well" [column ‘a’]

• Other Indo-European languages: No one 14 and over speaks English only or speaks English "very well" [column ‘b’]

• Asian and Pacific Island languages: No one 14 and over speaks English only or speaks English "very well" [column ‘c’]

• Other languages: No one 14 and over speaks English only or speaks English "very well" [column ‘d’]

% of English Proficient households = columns a + b + c + d / total ] * 100

==> Any Block Group with 25% or more of all households identified as English-isolated was selected as an EJ population.

Additional data adjustments:

The resulting set of blockgroups was further evaluated to remove the following:

• blockgroups which might have been selected erroneously due to the presence of a higher education institution (college student populations)

• blockgroups which might have been selected erroneously due to the presence of a correctional institution (inmate populations)

These Block Groups were identified with the 2010 group quarters totals in table P42, one of the Census 2010 redistricting (PL-94-171) files. Blockgroups with 65% or more of their total population living in university housing and/or correctional facilities for adults were removed from EJ. Additionally, blockgoups containing MCI-Concord and MCI-Framingham were eliminated.

Block Groups with a total population of zero were also removed.

Finally, approximately ten other polygons not agreeing with the conceptual idea of an “EJ population” were removed; these include blockgroups with very low populations (airports, industrial areas, parks) and blockgroups with no daytime population.

The datalayer is named EJ_POLY.