                                       
                        Analysis of Demographic Factors 
                         For Populations Living Near 
                           Lime Manufacturing Plants
                                       
                                       
                                 Prepared by:

                             SC&A Incorporated
                                       
                         1414 Raleigh Road, Suite 450
                            Chapel Hill, NC  27517
                                       
                                       
                                       
                           GSA BPA No. 68HERD21A0003
                         Task Order No. 68HERH22F0003
                                       
                                       
                                       
                                 Prepared for:
                                       
                                       
                          Air Toxics Assessment Group
                   Health and Environmental Impacts Division
                 Office of Air Quality Planning and Standards
                     U.S. Environmental Protection Agency
                 Research Triangle Park, North Carolina 27711
                                       
                                       
                                       

                                       
                                       
                                April 11, 2022
	Disclaimer

            Although the analysis described in this document has been funded wholly or in part by the United States Environmental Protection Agency under GSA contract 47QRAA20D002W / BPA 68HERD21A0003 to SC&A Incorporated, it has not been subject to the Agency's review and therefore does not necessarily reflect the views of the Agency, and no official endorsement should be inferred.
                                   Contents



1.	Introduction	1
2.	Census Data	2
3.	Calculation Methods	3
3.1	Race, Ethnicity and Age Categories	3
3.2	Level of Education	4
3.3	Poverty Level	4
3.4	Linguistic Isolation	5
3.5	Defaults	5
4.	Results	6
5.	Uncertainty Discussion	9
Appendix: Analyzed Facilities	10



 Introduction
	This document provides summary results and describes the approach used to evaluate the different socio-economic demographic groups within the population living near lime manufacturing plants in the United States (U.S.). The demographic analysis is for 35 facilities identified by the U.S. Environmental Protection Agency (EPA) as subject to the Lime Manufacturing Plants National Emission Standards for Hazardous Air Pollutants (NESHAP). The current analysis evaluates census blocks surrounding these facilities with census-based demographic data. This analysis presents the demographic composition of the population located within close proximity at 5 kilometers (km) and within 50 km of these facilities. The following demographic groups were included in this proximity analysis:      
     
 Total population;
 White;
 Minority;
 African American (or Black);
 Native Americans;
 Other races and multiracial;
 Hispanic or Latino;
 Children 17 years of age and under;
 Adults 18 to 64 years of age;
 Adults 65 years of age and over;
 Adults 25 years of age and older without a high school diploma;
 People living below the poverty level; and
 Linguistically isolated people.

	The current analysis used the Proximity Tool to (1) identify all census blocks with centroids located within specified radii of the latitude/longitude location of each facility, and then (2) link each block with census-based demographic data. It should be noted that, if the centroid of a census block is located within the specified radius, the entire population of that census block is counted as within the radius. In addition to facility-specific demographics, the Proximity Tool also computes the demographic composition of the populations within the specified radii for all facilities as a whole (e.g., source category-wide). The source category-wide computation takes into account neighboring facilities with overlapping study areas and ensures populations in common are counted only once in this demographic analysis. Finally, this analysis compares these source category-wide demographics at each specified radius (i.e., 5 km, 50 km) to the demographic composition of the nationwide population.
  
	The census data used in this analysis is described in Section 2. The algorithms used to compute the population of each demographic category surrounding the facility are presented in Section 3. The summary results of this analysis are presented in Section 4. The Appendix points to a supplemental workbook of spreadsheets containing the detailed facility-specific results.
 Census Data
	The total population within a specified radius around each facility is the sum of the population for every census block within that radius, based on each block's population provided by the 2010 Decennial Census. For the demographic analysis, statistics on total population, race, ethnicity, age, education level, poverty status and linguistic isolation are obtained from the Census' American Community Survey (ACS) 5-year averages for 2015-2019. These data are provided at the block group level. A census block group contains about 28 blocks on average, or about 1,400 people. Table 1 summarizes the census data used in the analysis, showing the source of each dataset and the level of geographic resolution. 

    Table 1.  Summary of Census Data used for Different Demographic Groups
Type of population category
Source of data
Level of geographic resolution
Total population (sum of block counts within radius)
2010 Census3 SF1
Census block
Total population (sum of block group counts, used for demographic percentages)
ACS4 Table B03002 (e1)
Census block group

Race/ethnicity categories (percentages):

 White (non-hispanic):
 Minority (non-white + hispanic)
 African American (non-hispanic):
 Native American (non-hispanic):
 Other & Mixed race (non-hispanic):
 Hispanic (all races):
ACS Table B03002, Hispanic or Latino Origin by Race (Tiger table X03):
 e3/e1
 (e1-e3)/e1
 e4/e1
 e5/e1
 (e6+e7+e8+e9)/e1
 e12/e1
Census block group
Age groups
ACS Table B01001, Sex by Age (Tiger table X01)
Census block group
Level of education  -  percentage of adults 25 years and older without a high school diploma
ACS Table B15002, Sex by Educational Attainment (Tiger table X15) 
Census block group
Individuals living in households earning below the poverty level (percentage of individuals)
ACS Table C17002, Ratio of Income to Poverty Level (Tiger table X17): (e2+e3)/e1
Census block group
Individuals living in linguistically isolated households (percentage of households)
ACS Table C16002, Household Language by Household (Tiger table X16): (e4+e7+e10+e13)/e1
Census block group

      The statistics for total minorities, age groups, educational attainment, poverty, and linguistic isolation are consistent with the demographic statistics used in EPA's EJSCREEN tool for Environmental Justice analysis. We derive our demographic statistics from the ACS, which is the source of data for EJSCREEN's statistics. For the current analysis, however, we provide the impact on different racial and ethnic groups in more detail, as Table 1 illustrates.
 Calculation Methods
	The Proximity Tool uses the census block and census block group identification codes to link each block to the appropriate ACS block group demographic statistics. This allows us to estimate the number of people in different demographic categories for each census block in a specified radius around each facility. As noted in Section 2, demographic data is available at the census block group level. To estimate more detailed block level demographic percentages for the purposes of this analysis, the demographic characteristics of a given block group  -  that is, the percentage of people in different races/ethnicities, the percentage in different age groups, the percentage without a high school diploma, the percentage that are below the poverty level, and the percentage that are linguistically isolated  -  are presumed to also describe each census block located within that block group.   

	For comparison, the nationwide demographic percentages are computed from the Census' ACS 5-year averages for 2015-2019 ("2019 ACS"). The denominator for these percentages uses the total nationwide population, which is likewise computed from the 2019 ACS and determined by summing the total population of all census block groups. We also provide the total population based on the 2010 Decennial Census for comparison, because the census block populations are based on 2010 Decennial Census data, as noted in Section 2. 

	Sections 3.1 through 3.4 describe calculation methods for racial, ethnic, age, education status, poverty status, and linguistic isolation demographic categories. Section 3.5 describes the gap-filling approach used when block group statistics are not available for a given block, based on computing default averages for the missing demographic(s) at the tract or county level.  
    Race, Ethnicity and Age Categories  

	Table B03002 (Hispanic or Latino origin by race) of the ACS data provides race/ethnicity statistics for each census block group nationwide. Table B01001 provides age statistics for the population by ranges (in years) for each census block group nationwide. For each census block in this analysis, the race/ethnicity (White, African American, Native American, Multiracial/Other, and Hispanic or Latino) and age range (0-17, 18-64 and >=65 years) for that block is estimated based on the demographic information provided at the block group level, as follows:

		N(s,b/bg) =  N(t,b/bg) x P(s,bg) ∕ 100	
where:

	N(s,b/bg) =	number of people in racial/ethnic or age subgroup "s", in block "b" of block group "bg"
	N(t,b/bg) =	total number of people in block "b" of block group "bg"
	P(s,bg) =	percentage of people in racial/ethnic or age subgroup "s", in a block group "bg"	

The number of people in each racial/ethnic and age category is calculated using the above equation, summed over all blocks that fall within the specified radius of each facility.
    Level of Education

	Table B15002 (educational attainment) of the ACS provides education attainment statistics for each census block group nationwide. For each census block in this analysis, the number of people 25-years and older without a high school diploma is estimated based on the demographic information provided at the block group level, as follows:

		N(nhs,b/bg) =  N(t,b/bg) x P(nhs,bg) ∕ 100	
where:

	N(nhs,b/bg) =	number of people 25-years and older without a high school diploma "nhs", in block "b" of block group "bg"
	N(t,b/bg) =	number of people 25-years and older in block "b" of block group "bg"
	P(nhs,bg) =	percentage of people 25-years and older without a high school diploma "nhs", in a block group "bg"	

The number of people 25-years and older without a high school diploma is calculated using the above equation, summed over all blocks that fall within the specified radius of each facility.
3.3	Poverty Level

	Table C17002 (poverty) of the ACS estimates the numbers of individuals within a Census block group who live in households where the household income is below the poverty line, and below various multiples of the poverty line. For this analysis, we calculate the fraction of individuals living in households earning incomes below the poverty level. For each census block in this analysis, the block's household income level is estimated based on the demographic information provided at the block group level, as follows:

	N(hi,b/bg) =  N(t,b/bg) x P(hi,bg) ∕ 100

where "hi" indicates household income below the poverty level, and:
	
	N(hi,b/bg) = 	number of people living in households "hi" below the poverty level, in block "b" of block group "bg"
	N(t,b/bg) =	total number of people in block "b" of block group "bg"
	P(hi,bg) =	percentage of people living in households "hi" below the poverty level, among the population for which poverty status is known, in block group "bg"

The number of people living in households earning below the poverty level is calculated using the above equation, summed over all blocks that fall within the specified radius of each facility.
3.4	Linguistic Isolation

      Linguistic Isolation is defined by in the ACS as "a household in which all members age 14 years and over speak a non-English language and also speak English less than "very well" (have difficulty with English)." Table C16002 (Tiger table X16_language_spoken_at_home) of the ACS provides the number of households in linguistic isolation in each block group. For each census block in this analysis, the number of people living in linguistic isolation is estimated based on the demographic information provided at the block group level, as follows: 

		N(li,b/bg) =  N(t,b/bg) x P(li,bg) ∕ 100	
where:

	N(li,b/bg) =	number of people living in linguistic isolation "li", in block "b" of block group "bg"
	N(t,b/bg) =	total number of people in block "b" of block group "bg"
	P(li,bg) =	percentage of linguistically isolated households "li", in block group "bg"	

The number of people living in linguistic isolation is calculated using the above equation, summed over all blocks that fall within the specified radius of each facility.
 	Defaults

      Block and block group designations used in the Census may be modified to accommodate population growth in some regions. As a result, certain blocks which are based on the last Decennial Census, may not map to the block group designations used in the latest 5-year ACS survey. In addition, some statistics may not be reported in the ACS for every block group. Race, ethnicity, and age statistics are generally reported for all block groups. However, poverty, linguistic isolation, and educational attainment statistics are not available for some block groups.
      
      In these cases, we compute default estimates for the missing demographic statistics based on the average statistics for the tract in which the block is located. If no tract-level data are available, demographic statistics are estimated based on the overall demography of the county in which the unmatched block is located. This gap-filling exercise is performed separately for each type of demographic data. That is, in the case where some categories of data are available (for instance, race, age and ethnicity) and others are not available (educational attainment, poverty, or linguistic isolation) we only compute defaults for the categories of data that are missing.
      
      The tract level defaults are computed using weighted averages based on all of the other block groups in the tract for which data are available. Defaults are calculated as follows for race, ethnicity, and age subgroups:

		P(s,T) =  { ∑ P(s,bg/T) x N(t,bg) } ∕ {∑ N(t,bg)}	
where:

	P(s,T) =	percentage of people in race, ethnicity, or age subgroup "s", in tract "T"
	∑	refers to the summation over all block groups in tract "T" for which data are available
	P(s,bg/T) =	percentage of people in race, ethnicity, or age subgroup "s", in a block group "bg" of tract "T"
	N(t,bg) =	total number of people in block group "bg"

Defaults for educational attainment, poverty, and linguistic isolation are calculated in a similar fashion, except that the population weighting term N is replaced by the population over age 25, the population for which poverty status is known, and the number of households, respectively. County level defaults are also calculated in a similar way, except that data are summed over the county instead of the tract.

      Results
	The proximity results describe the demographics of the population surrounding these facilities engaged in Lime Manufacturing. Table 2 presents the demographic composition of the population located within a close proximity of 5 km and within 50 km of the 35 facilities as a whole (source category). For context, Table 2 also provides the nationwide percentages of these various demographic groups. The detailed facility-specific results underpinning these source category-wide results are noted in the Appendix.

	The proximity results presented in Table 2 indicate that the population percentages for certain demographic groups within 5 km of the 35 facilities are greater than the corresponding nationwide percentages. The demographic percentage for populations residing within 5 km of facility operations is 18 percentage points greater than its corresponding nationwide percentage for the Hispanic and Latino population (37% within 5 km of the facilities compared to 19% nationwide), 16 percentage points greater than its corresponding nationwide percentage for the population living in linguistic isolation (21% within 5 km of the facilities compared to 5% nationwide), 14 percentage points greater than its corresponding nationwide percentage for the population living below the poverty level (27% within 5 km of the facilities compared to 13% nationwide), 10 percentage points greater than its corresponding nationwide percentage for the minority population (50% within 5 km of the facilities compared to 40% nationwide), and 5 percentage points greater than its corresponding nationwide percentage for the population 25 years old and older without a high school diploma (17% within 5 km of the facilities compared to 12% nationwide). The remaining demographic groups within 5 km of facility operations are less than, or within one percentage point of, the corresponding nationwide percentages.

      In addition, the proximity results presented in Table 2 indicate that the population percentages for certain demographic groups within 50 km of the 35 facilities are greater than the corresponding nationwide percentages. The demographic percentage for populations residing within 50 km of the facility operations is 5 percentage points greater than its corresponding nationwide percentage for the African American population (17% within 50 km to the facilities compared to 12% nationwide), 3 percentage points greater than its corresponding nationwide percentage for the population living below the poverty level (16% within 50 km of the facilities compared to 13% nationwide), and 2 percentage points greater than its corresponding nationwide percentage for the population living in linguistic isolation (7% within 50 km of the facilities compared to 5% nationwide). The remaining demographic percentages within 50 km of the facilities are less than, or within one percentage point of, the corresponding nationwide percentages.

Table 2.  Summary of Demographic Assessment for Lime Manufacturing: Proximity Statistics
                                       
                               Population Basis
                             Demographic Group[1]
                                       
                                     Total
                                  Minority[2]
                               African 
American
                               Native 
American
                             Other and
Multiracial
                             Hispanic
or Latino[3]
                                 Ages 0 
to 17
                                Ages 18 
to 64
                                Ages 65 
and up
                         Over 25 Without a HS Diploma
                            Below the Poverty Level
                                       
                                       
                            Linguistic Isolation[4]
Nationwide Demographics    (2015-2019 ACS)
                                 328,016,242  
                                      40%
                                      12%
                                     0.7%
                                      8%
                                      19%
                                      22%
                                      62%
                                      16%
                                      12%
                                      13%
                                      5%
Nationwide Block Counts 
(2010 Decennial Census)[5]
                                  312,459,649
                                       

                                 Proximity[6]
                   Population Surrounding the 35 Facilities
                              Lime Manufacturing
                                     50 km
                                  21,999,863
                                      40%
                                      17%
                                     0.3%
                                      6%
                                      17%
                                      22%
                                      62%
                                      16%
                                      12%
                                      16%
                                      7%
                              Lime Manufacturing
                                     5 km
                                    473,343
                                      50%
                                      9%
                                     0.9%
                                      3%
                                      37%
                                      23%
                                      60%
                                      17%
                                      17%
                                      27%
                                      21%
Notes:
[1] The demographic percentages are based on the Census' 2015-2019 American Community Survey five-year averages, at the block group level, and include the 50 states, the District of Columbia, and Puerto Rico. Demographic percentages based on different averages may differ. The total population of each facility and of the entire run group are based on block level data from the 2010 Decennial Census. Populations by demographic group for each facility and for the run group are determined by multiplying each 2010 Decennial block population within the indicated radius by the ACS demographic percentages describing the block group containing each block, and then summing over the appropriate area (facility-specific or run group-wide).
[2] Minority population is the total population minus the white population.
3 To avoid double counting, the "Hispanic or Latino" category is treated as a distinct demographic category for these analyses. A person is identified as one of five racial/ethnic categories above: White, African American, Native American, Other and Multiracial, or Hispanic/Latino. A person who identifies as Hispanic or Latino is counted as Hispanic/Latino for this analysis, regardless of what race this person may have also identified as in the Census.
[4] The linguistically isolated population is estimated at the block group level by taking the product of the block group population and the fraction of linguistically isolated households in the block group, assuming that the number of individuals per household is the same for linguistically isolated households as for the general population, and summed over all block groups.
[5] The nationwide 2010 Decennial Census population of 312,459,649 is the summation of all Census block populations within the 50 states, the District of Columbia, and Puerto Rico. Block level population used by the Proximity Tool will be updated based on the 2020 Decennial Census, once processed and quality-assured for these analyses.
6 The population tally and demographic analysis of the total population surrounding all facilities as a whole takes into account neighboring facilities with overlapping study areas and ensures populations in common are counted only once.


 Uncertainty Discussion
      
	Our analysis of the distribution of population across various demographic groups is subject to the typical uncertainties associated with census data (e.g., errors in filling out and transcribing census forms), which are generally thought to be small, as well as the additional uncertainties associated with the extrapolation of census block group data down to the census block level.  

	The methodology for our demographic analyses applies demographic data from the Census American Community Survey (ACS). While this is our best attempt to provide useful information now, our thinking is continuously advancing. The EPA has developed technical guidance for environmental justice analyses. We present these analyses, with their associated uncertainties, to EPA decision makers and the public as additional analyses to inform Risk and Technology Review decisions. 





Appendix: Analyzed Facilities

A workbook of spreadsheets containing the detailed facility-specific results underpinning the source category-wide results are provided in the file entitled "Lime Manufacturing Facility-Specific Demographic Results 2022-04-11.xlsx". The dataset covering these facilities at both 5 km and 50 km makes the data more amenable to Excel(R) spreadsheets, than a Word(R) document.

