United States
Environmental Protection
Agency
Atmospheric Sciences Research
Laboratory
Research Triangle Park NC 27711
'/i
Research and Development
EPA/600/S3-85/076 Jan. 1986
Project Summary
Determination  of  Materials
Distribution  in  Suburban  and
Rural  Areas

Marshall A. Atwater, Douglas R. Murray, and John E. Yocom
  The program was undertaken to as-
sist in the  quantification of material
exposed in  suburban and rural areas
that  is susceptible to the effects of
gaseous and particulate  air pollutants
and acidic  deposition.  The  study is
based on a limited visual survey and
photogrammetric  measurement pro-
gram to provide sufficient information
on the amount and distribution of
materials in suburban and rural areas.
The study areas were selected to ac-
commodate a variety of demographic
and related variables such as structure
sizes, structure ages, and household
incomes as indicators of material in use
in Tucson,  AZ, Charlotte, NC, and
Lincoln, NE.
  Confidence limits and stepwise mul-
tiple linear  regression were used to
derive the area and amount of materials
for single family housing. The exposed
materials most prevalent in  all cities
were painted wood and  brick. Stucco
was also predominant in Tucson. Re-
sults are presented for rural farms and
for public facilities, utilities, and bulk
storage facilities.
  This Project Summary was developed
by EPA's Atmospheric Sciences Re-
search Laboratory. Research Triangle
Park, NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).
Introduction
  A critical element in determining the
economic losses due to damage to struc-
tural materials from gaseous and partic-
ulate air pollutants and acidic deposition
is the estimation of the amount of mater-
ial-at-risk. A recent study that developed
an economic  materials damage model
showed that uncertainty in lifetime main-
tenance costs for different pollution con-
trol scenarios is strongly influenced by
existing uncertainty in material distribu-
tion estimates.  Previous studies  have
generally concentrated on urban areas.
This report presents information on ma-
terial in place within the suburban and
rural environments and thus provides a
wider basis for  calculating  materials
damage and the related economic impact
due to the effects of gaseous and partic-
ulate pollutants and acidic deposition.
  The objective of this  project was to
develop mathematical models which are
relatively accurate and easy to apply for
estimating the distribution of exposed
materials  susceptible to air  pollution
damage in suburban and rural areas. To
accomplish this objective, representative
suburban  and rural areas were selected
for study.  Readily available census data
served as estimators of the distribution of
materials. The selected areas were exam-
ined photographically to determine the
amounts of specific susceptible materials.
A statistical relationship between the
estimators and the amounts of suscep-
tible materials was developed.
  The materials of concern  in this study
are those used in suburban and  rural
stationary structures having  surfaces
exposed to the atmosphere and therefore
susceptible to damage by  gaseous air
pollutants and acidic  deposition. Com-
mercial, industrial, and multifamily hous-
es were excluded from the study. Mater-
ials of interest and their coatings are

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stucco, wood (bare, painted, and stained),
brick (bare and painted), steel (galvanized
and painted), aluminum, concrete, cloth,
wrought iron, stone, window, limestone,
and marble.
  Estimates of the amounts of materials
in each of the three cities using regres-
sion analysis are shown in Table 1.
Procedure
  Two overall tasks were  designed to
meet the goals of the work: data gathering
and model development and testing. Data
on  the materials-in-place  at six sites
consisting of the suburban and rural areas
near  Charlotte,  NC, Tucson, AZ, and
Lincoln,  NE, were obtained from an
analysis of Sanborn maps, a review of
public and  commercial sector  mainte-
nance records, and the field measure-
ment of a statistical sample of buildings,
fences, and  outdoor fixtures. Data on
climate,  demographics, industrial and
commercial activities, land use, and hous-
ing characteristics were obtained from
sources such as the U.S. Census Bureau
and local planning commissions and were
analyzed to find appropriate  factors for
predicting the amounts of materials-m-
place.
  The materials-in-place analysis was
divided into three  sections: suburban
residential, rural farms, and non-popula-
tion-dependent materials. For the sub-
urban residential and rural areas, photo-
graphic analysis and visual  field surveys
were used to gather the distribution (type
and amount) of materials-m-place.  For
the non-population-dependent materials,
defined as highways, bridges, guardrails,
radio and TV towers, and telephone  and
electrical  communication  lines,  a tele-
phone survey was  used to gather  the
data.
  The census tract was chosen as the
basic geographic study unit to  obtain a
sample of homes of various ages  and
sizes with residents of various income
levels. This selection includes data which
could be used as possible  predictors in
the regression analysis and which might
be  related to the type and  amount of
materials. Further,  data  from  census
tracts were available to form a data base
for an analysis on a regional basis.
  The census tract  data were reviewed,
and a total of ten residential suburban
tracts were  selected for study in each
geographic area. These tracts were se-
lected to ensure a variety of housing ages,
of  household incomes, and of structural
sizes. A photographic  survey was con-
Table 1.    Estimates of the Amounts of
          Materials in Each of the Three
          Cities (10s ft2) Using Regression
          Analysis
Charlotte
Painted Wood
Brick
Aluminum
Lincoln
Painted Wood
Stained Wood
Brick
Aluminum
Tucson
Stucco
Painted Wood
Stained Wood
Brick
Aluminum

302.9
340.9
29.8

70.5
6.3
70.3
9.1

112.8
104.0
20.8
54.4
91.0
ducted of each selected census tract. The
survey consisted  of pictures of twelve
typical houses and detailed photographs
for one typical structure in each tract. The
first set of photographs  established the
distribution  of  materials  and  size  of
houses  within each tract. The detailed
photographs of the one typical house in
each tract showed the surface area com-
ponents for different parts of the struc-
ture, including walls, windows, founda-
tion, doors, door trim, wall trim, window
trim, and gutters.  The photographic sur-
vey also yielded information on materials
associated with basketball backboards,
light posts, birdbaths, clothesline poles,
railings,  and  air conditioners. Standard
measurements were developed for each
of these structures.
  These data were summarized to yield
total  amounts  of each material type
expressed  in  square feet of exposed
surface  area. Confidence limits of area
were developed for each city. Additionally,
stepwise multiple linear regression was
used to derive  mathematical equations
using the material-in-place as the inde-
pendent variable and the census data as
the dependent variable for the suburban
residential study areas.
   A similar approach  was taken for the
rural areas surrounding  the three cities.
Detailed visual  surveys  were conducted
on five  farms in each city. Detailed
photographs  were taken  of the  main
house, all outbuildings and sheds, includ-
ing barns, pigstyes, coops, storage silos,
and farm implements. The material types
were determined  from field survey notes
and the detailed site photographs.
  For the  non-population-dependent
material-in-place calculations, telephone
surveys were conducted  in each geo-
graphic  area. Information was gathered
from state  and county road and  public
works departments,  petroleum storage
facilities, and electric and other  public
utility firms on the type of material and
the distribution of structures within the
geographic area.

Summary and Conclusions
  Photographs were taken of houses in
Charlotte, NC, Lincoln, NE, and Tucson,
AZ.  The areas  measured include the
fronts of 80 houses and all surfaces for 10
houses  in each of the three cities.  Meth-
ods  were  developed to  estimate the
amount  of mterials-in-place  using  (1)
confidence limits and(2) regression anal-
ysis. The census data on housing and
population  were combined with the area
data computed from the photographs.
The amount of materials-in-place on five
farms in each of the regions was comput-
ed  from photographs. Additional non-
population-dependent materials  in the
suburban and rural areas were estimated
by  means  of telephone  surveys with
public agencies and large corporations in
the regions.
  A  comparison of the regression equa-
tions and  the confidence limit method
showed variations  in the estimates of
materials-in-place  of 20 to 30 percent.
Either method appears  capable of esti-
mating  the materials-in-place. However,
additional data should be collected or the
procedure  should be varied to improve
the reliability of the estimates.
  The confidence  limits method  needs
additional data on the ratio of the front to
the  total exposed  area. In the present
case, the ratio was  estimated from the
detailed analysis of 10 houses. A number
of nonphotographic  sources of data are
available, such as multiple listing servic-
es, that provide actual floor plans.
  The regression analysis will need ad-
ditional data points.  In the present anal-
ysis, demographic  or housing data of
individual  houses were  not  available.
Thus, the demography and housing were
represented by census tract data.
  The methods of the present study can
be  used to  estimate  the amount of
materials  in a given region. The basic
data, the  census  data,  are available
nationwide. However, additional sites will
need to be sampled  to provide the basic
area of the structures. Additional data are
needed to  quantify the surface areas for
industrial and commercial structures and
for multifamily housing  units.

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Recommendations
  A continuing  criticism  of  economic
assessments of air pollution effects on
susceptible materials  exposed outdoors
is the uncertainty of the amount  of
exposed materials-in-place on  a nation-
wide scale. The study was undertaken to
provide an initial basis for estimating the
amount of exposed materials in suburban
residential  and  rural  farm areas. To
expand our knowledge of  materials-in-
place and provide accurate estimates of
material-at-risk for assessment of mater-
ial damage as part of the  National Acid
Deposition  Assessment Program (NAD-
AP), the following recommendations are
made:

• Apply these mathematical techniques
   to calculate material-at-risk due to the
   effects of gaseous and particulate air
   pollutants and acidic deposition within
   given regions. Integrateairqualitydata
   and damage functions to  calculate total
   material damage costs  and  that pro-
   portion attributable to air pollution.
• Conduct a random sampling of res-
   idential  census tracts in other geo-
   graphic  regions using similar photo-
   grammetric techniques  to expand the
   accuracy of the methods.
• Expand the study to multiunit residen-
   tial housing. The types of materials in
   use and any substitution practices will
   be different from those noted in single
   family residential structures.
• Select tracts which have representa-
   tive numbers of industrial/commercial
   structures so these applications could
   be included in the aggregate estimate
   of material-m-place.
• Treat urban and suburban areas as a
   unit.
• Use existing census data for the basic
   building  data.

  Information gathered  in these  areas
will result in improvements to the esti-
mating techniques for the potential bene-
fits and costs due to changes in ambient
concentrations of atmospheric pollutants.
Marshall A,  Atwater, Doug/as R. Murray, and John E.  Yocom are with TRC-
  Environmental Consultants. Inc., East Hartford. CT061O8.
Jon Gerhard is the EPA Project Officer (see below).
The complete report, entitled  "Determination  of Materials  Distribution  in
  Suburban and Rural Areas," (Order No. PB 86-128 600/AS; Cost: $16.95,
  subject to change) will be available only from:
        National Technical Information Service
        5285 Port Royal Road
        Springfield, VA 22161
        Telephone: 703-487-4650                             '
The EPA Project Officer can be contacted at:
        Atmospheric Sciences Research Laboratory
        U.S. Environmental Protection Agency
        Research Triangle Park, NC 27711

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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use S300

EPA/600/S3-85/076
                                           IL
                                                  60604

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