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approach
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U.S. ENVIRONMENTAL PROTECTION AGENCY
    WASHINGTON, D.C. 20460

       September 1974

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RAPS:  a new
approach to  air  pollution
 T"1 he largest, most comprehensive investigation of
    air pollution ever undertaken is now in prog-
 ress—and it is being conducted here in the St.
 Louis metropolitan area.
   The project is the Regional Air Pollution Study
 or, more simply, RAPS. It is being conducted by
 the U.S. Environmental Protection Agency (EPA)
 to develop models for testing air quality manage-
 ment techniques that will  help curb air pollution
 in greater St. Louis. That  alone would be enough
 to  merit attention, but  there is more. RAPS is
 also a major pilot study; what is learned here will
 be applied in other cities  and other nations.
   Because RAPS and its results are important to
 you, as well as to your brothers and sisters  here
 and around the world, this  leaflet  has been pre-
 pared so that you will know what is happening,
 why it is happening, and what it will mean.

 The problem
   Air pollution is recognized as a real problem
 that poses a very real threat to our health and our
 environment. The evidence is extensive:  scientific
 studies  have been made, documented  evidence
 compiled, and brought before Federal,  State and
 local governments. Virtually everyone has come
 to realize that there are dangers, real and potential,
 from air pollution.
   But at  the same time,  there  is a feeling,  par-
 ticularly among young people like yourself, that
 this public  awareness has not been followed by
 enough action.  If the problem is immediate, they
 maintain,  the solutions should be too. They feel
 that little progress is being made against this
 threat to health and the environment.
   It may seem that way but it is not so. Far more
 is being done than you might imagine.  EPA and
 State and local government  environmental agen-
 cies have long  been  active  enforcing pollution
 control  laws passed by Congress.

 So why does  the  problem continue?
   One  stumbling  block to  achieving  clean air
 is resolving situations which  involve conflicts and
 compromises between  enforcing  agencies  and
 polluters, large and small. How do we take cor-
 rective action without getting harmful side effects?
 For instance, we could clean up the air by elimi-
 nating  the  major  sources  of  pollution—cars,
trucks, trains, planes and industry. But this is not
practical. What would happen if we could not
produce the food, clothing and  other goods we
need for life itself?  We  must seek to meet air
quality  standards, keeping  pollution at a  low
enough  level to  protect the public health  and
welfare and at the same time maintain our quality
of living. To do this, we must obtain information
as complete and  as accurate as  possible  so  that
we can better evaluate what is the proper action
to take.

Is that what  RAPS will  do?
   That's precisely what  RAPS  will do.  It  will
give us a more detailed measurement of air pollu-
tion than we have ever had before. RAPS  will
feed  those measurements into computers to ob-
tain answers  and allow predictions  to  be made
under various pollution conditions.  And RAPS
will test a variety of methods for controlling pollu-
tion.  It will enable us to check alternative strate-
gies,  and determine  what really works best to
bring pollution under control.

How will  RAPS  change things?
   RAPS will greatly enlarge on what we currently
know about how much pollution  is in the air and
how  much  we  can tolerate.  RAPS will  tell us
about the air above each part of our  metropolitan
region. It will reveal what pollutants exist over
each area, the direction in which they are moving,
and what chemical changes occur as pollutants
mix and as they are exposed to sunlight and other
elements. With  such detailed measurements  and
through  computer  analysis,  scientists  hope to
develop mathematical models that will guide us
toward accurate and  effective control procedures.
   In short, RAPS is designed to provide the in-
formation which will be the basis for reasonable
and  effective air pollution  controls—and while
gathering the information it will test which air
pollution control strategies work  best.

How is RAPS organized?
   RAPS is a $22 million, 5-year scientific proj-
ect funded and conducted by EPA. The Rockwell
International Corporation is the  prune contractor
and  several subcontractors  from the St. Louis
area will handle specific jobs such as equipment
installation or data management. Numerous local,
State, and  Federal agencies are cooperating  in
the project, and qualified local college students are
participating in some of the field studies and meas-
urements. When it is completed  RAPS will make
it easier for EPA to control air pollution. For you
it will mean cleaner air to breathe.

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                                                                       100R74O11
Why  St.  Louis?
  It's  a good question. Your city doesn't have
the cleanest air in the Nation, but neither does it
have the  dirtiest.  So why was  it selected? This
area was  chosen for several  reasons.
  Of 33 American cities, St. Louis was found to
be similar to the other 32. Your city has a climate
that is most like the majority of other U.S. urban
areas.  It has a wide variety of emissions as deter-
mined by fuels used, industrial production proc-
esses  and pollution  mix.  It  is  also reasonably
isolated from the pollution of other major sources
outside the area.  It is  far from the  oceans  and
Great  Lakes,  hills and mountains, all  of which
can have  an  effect  on air  pollution.  And  the
greater St. Louis  region is also large enough to
conduct this study.
  Finally, St.  Louis has had  previous air pollu-
tion studies and the continuing work of existing
environmental agencies  provides available back-
ground information,  particularly in the area  of
meteorology, emissions  and air  quality.

How  will RAPS  be  carried out?
  In order to properly  study the region, covering
roughly a 25-mile radius from the Gateway Arch,
a network of  25  remote  air monitoring stations
has been established. Stations  will also be located
in the greater  St.  Louis  area in both Missouri
and Illinois. (See map.) In addition, this network
will be supplemented by 10  monitoring  stations
opsrated by local  agencies.

  Each station contains analytical equipment to
measure pollutants and meteorological conditions,
plus a minicomputer to acquire the data  and
transmit information to a central  headquarters.

  Information  will  also be gathered by mobile
vans and aircraft. The highly advanced electronics
equipment used in  the monitoring stations  also
will be contained in mobile units. On the ground
we  will be monitoring the hourly emission rates
of  smokestacks  and calculating  emission  rates
through plant fuel consumption or plant  process
schedules. Helicopters and fixed-wing aircraft will
sample the air. Photography  and  radar  will be
used to study  air pollution  rising up  from  the
street and river traffic and from the railroads.  We
are even  going to check the effects aircraft may
have on the problem, including that of our  sur-
veillance aircraft.
  This is  what RAPS is really all about, collecting
and evaluating  information  needed  to  test  our
clean air strategies.
So what in particular will RAPS be
involved with?
  A great many things. The investigation will be
conducted across the wide spectrum of the physi-
cal  sciences and will include some of the  social
sciences as well: meteorology, atmospheric chem-
istry,  aerosol physics, applied  mathematics  and
even  health and welfare studies  and economic
analysis.  All will be employed to  gather  and
evaluate the information about  air pollution.
  Information gathered on a continuous basis will
be available for automatic retrieval. Scientists will
use it to develop mathematical models which  de-
scribe air pollution under virtually any circum-
stances. Proposed methods for controlling  pollu-
tion can be tested against the  models. Scientists
also expect  to evaluate such new remote sensors
as lidar and acoustic sounders.  Research for the
project is being conducted nationwide by a variety
of  institutions.  Locally, Washington University
is studying  how gas pollutants  change into par-
ticles in  the air. Students  and  instructors  at St.
Louis University and the University of Missouri
are looking into the relationship between pollution
and vegetation,  i.e.,  how plants act  as filters to
remove particles from the air.
   The analysis  and  re-analysis will be done  at
the central support facility located in Creve Coeur.
It houses both manual and  automated data proc-

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THE SCENE  AT  ST.  LOUIS:

Below, a lab technician inspects large plastic
bags that will be used for ah- samples taken
with the help of equipment (lower right) in
each of the 25 Regional Air Monitoring Sys-
tems (RAMS)  throughout the greater St.
Louis  area (far right). At middle  right is
computer, built by Rockwell  International,
that receives  and  stores  data  from  the
RAMS. Weather maps, right, are  important
aids in  the RAPS  program.

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essing equipment and is linked to the monitoring
stations that are scattered throughout the city via
telephone circuits. The support facility also has
offices and a  laboratory for instrument mainte-
nance and repair.

We  think  RAPS is pretty important
   So do a lot of  other people. The information
gathered will  not  only be  studied by your  State
and  local environmental agencies,  but  by those
of foreign governments as well. Under a protocol
agreement  between  the  United  States  and the
Soviet Union,  the two  countries will study and
evaluate the data collected from RAPS—St. Louis
and  a similar  study  now underway  in the Soviet
city  of Leningrad. During  the next several years
representatives of  Russia  and other nations will
be visiting your city  to observe the  RAPS opera-
tion  firsthand.

What can  students do to help?
   RAPS is  truly  a  program for the people. Its
primary goal  is to give you  and your parents  a
better life, one in which the air will be clean.
   The most important thing you can do is to tell
your  parents  and your friends about RAPS. For
if  RAPS  is to  be successful, we will need the
understanding and cooperation  of St. Louis  area
citizens. There will be some minor inconveniences.
The  helicopter flights, for instance,  will  be noisy
because we need helicopters to handle the meas-
uring  equipment.  Those   flights will  be  made
during February, August and November for the
next three years. If you help explain RAPS, you
will  help people understand  the need for  those
nights.
   RAPS also  will  involve measurements of emis-
sions from smokestacks at  major industrial loca-
tions  in ths area.  These will involve the use  of
laser  beams,  and  new remote  sensors to detect
pollution will  be tested. For these  parts  of the
RAPS program, cooperation will be needed from
business and industrial leaders.  If you help  make
RAPS known in St. Louis, you  will be helping
us to obtain that cooperation.
   We hope you will agree that RAPS is important
to us all. If you would like  to get further involved
in the type of  work that RAPS  will  be concerned
with, here are  several experiments for you  to
try in your classroom. They all  deal with air, and
are divided into intermediate and high school level.
Although these experiments  are  not as sophisti-
cated  as those  that  will  be  conducted by _ the
RAPS program, they will give  you  a visual idea
of the pollution problems  in St. Louis.

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                Experiments
    Reproduced from "Air Pollution Experiments for Junior
    and Senior High School Science Classes" (Second Edition)
    with permission of the Air Pollution Control Association,
    Pittsburgh, Pa.

              INTERMEDIATE—AIR

                      CONCEPT
    Acid gases and aerosols are prime ingredients of
    urban air  pollution.  These gases may  damage
    plants,  corrode  metals,  crumble  stone,  and  in
    heavy concentration,  they can  make  men  and
    animals ill.
                    EQUIPMENT
     A  large funnel, an air pump  or aspirator (most
    pet shops sell air pumps), filter papers,  one for
     each exposure site, large enough to  cover the
     large end of the funnel,  a piece of wire screen
    the same size. Tape to hold filter paper on funnel,
     1 ounce of 0.01M sodium bicarbonate solution, 1
     ounce of glycerin, 2 or 3  ounces of a dilute solu-
     tion of 10 percent hydrochloric acid  in a beaker,
     3  eye-dropper bottles, 2  or 3 feet of  rubber or
    glass tubing, chart and graph. (See Figure 1 and
    Figure  la.)

                    PROCEDURE
     Cut filter paper big enough to fit over the large
  opening  of  the  funnel  with  a Vi-inch overlap.
  Tape it on.  Add a drop of glycerin to the center
  of the paper. Add a drop of the indicator solution
  to the center of the paper. More drops may be
  necessary if the color is not apparent. Add a drop
  of sodium bicarbonate solution to the center  of
  the paper.
  [NOTE: Support the filter paper with a piece  of
  wire screen cut to fit over the opening of the
  funnel if the moistened paper cannot  withstand
  the flow of air through it without rupturing. Place
  the screen  on the funnel, then place the paper
  over it. Secure both with tape  or a rubber band.]
  Attach the tubing  to the small end of the funnel
  and to the air pump. Start the air pump and the
  timer. Do  a preliminary  test, drawing  air from
  above the open bottle of dilute hydrochloric acid.
  Stop the pump when a red color is visible.
  Test some air: Take samples from  a  chemistry
  laboratory, outdoors, hi a kitchen, from exhaled
  breath. Record the results on a chart and bar
  graph  to illustrate the presence of acid gases  at
  the test site. (See Figure la.)>Record on the chart
  the site location, the time you started taking the
  air sample,  and  the time the treated filter paper
  began  to react with the gases. Show the elapsed
  time figures  in the form of a bar graph.  Then you
  will have a complete picture of the acid gas con-
  centrations encountered in the test.
Figure 1
Air Assembly


Figure la
Air Graph
                              STARING   STOPPING   ELAPSED TIME  (Show in form of bar graph)
                      SITE     TIME        TIME
                        A 	

                        B  	
                        C 	
                        D 	
                        E  	

                        F  	

                        G 	

                        H 	
0    5   10   15  20  25   30   35   40  45 *
                     (MINUTES)

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          HIGH  SCHOOL—AIR
                  CONCEPT
This experiment  demonstrates  that  the  air in
which we live and which we breathe is not always
as clean as it appears to be.

                EQUIPMENT
Small vacuum pump or water aspirator having an
air  volume capacity of approximately  %  cubic
foot per minute. Two  pieces of 28-mm (outside
diameter) glass tubing 50- to 75-mm long, with
1.2-mm wall thickness (be sure glass  tubing  is
cut square and the ends are fire polished to avoid
cut fingers). Window screen disc cut 28-mm in
diameter, two rubber stoppers to fit glass tubing.
Each stopper to have an  8-mm hole in center.
Two 75-mm pieces of 8-mm outside diameter glass
tubing. Whatmann #41 filter paper 28-mm diam-
eter discs, rubber band, 1-inch wide, to  fit snugly
around  28-mm tubing, or 1-inch masking  tape,
burette stand  with a 3-finger clamp, plastic (Tygon
or Nalgon) or rubber  tubing to connect filter to
vacuum pump and to act as a probe to collect
outdoor air, flowmeter (rotameter) of  appropriate
range, or a wet or dry gas meter if available. A
critical  orifice of  proper size  may be  used to
control  air flow at the  maximum rate desired.
Glass bottle  (1-gal. capacity) fitted with 2-hole
rubber stopper containing one long and one  short
piece of 8-mm glass tubing. The bottle should be
nested in a corrugated board box for safely.

         ASSEMBLE APPARATUS
Set the  screen on  top  of one  piece of 28-mm
tubing (now called cylinder #1).
Place a  filter  paper disc on the screen.
Place the other piece of  28-mm tubing (cylinder
#2) on top of the filter paper, press the two cyl-
inders together and make  an air-tight seal  with
the rubber band or  with masking tape.
Insert a small glass  tube in a hole through each
rubber  stopper.  Place one stopper in the  lower
end  of  cylinder  #1  and the other stopper in the
upper end of cylinder #2. Mount the assembly
in the  burette  stand with  cylinder #2 in the
upper position.

Using plastic or rubber tubing,  connect cylinder
#1  to  the lower tap on the rotameter or to the
inlet of other type of flow measuring device. Con-
nect the outlet of the rotameter or other flowmeter
to the inlet side (long glass tube) of the 1-gallon
bottle. (This bottle evens out any fluctuations due
to the vacuum pump.  It is called  a surge or buffer
bottle.)
Similarly connect the outlet tube from the  surge
bottle to the inlet tap of the vacuum pump or
other source of vacuum.
Connect a long  piece of plastic or rubber tubing
to the inlet end of cylinder #2, and pass the other
end  through  a  window. The stem of the funnel
should be inserted in the tubing  hanging outside.
The  funnel should hang upside down to prevent
rain  from entering the tubing.

                PROCEDURE
Start the vacuum pump  and record  the  time.
Measure and record  the rate of  air flow.
Allow air to pass through the filter for two hours
or as long as required to  darken the filter paper
noticeably.
Measure and  record  the  rate of air  flow.  Stop
the vacuum pump and record the time.
Dismantle  and  observe the soiling of the  filter
paper.
If a photometer  to measure  transmittance of
light through ths soiled filter paper is available,
a quantitative evaluation of the amount of soiling
can  be  made.

       QUANTITATIVE  EVALUATION
Theory—The amount  of  discoloration on  the
filter paper is approximately proportional to the
quantity of solid particles suspended  in the  air.
This makes it possible  to  relate the decrease in
light transmittance  through the  paper to  the
amount of  particles  collected  on  it.  The  light
transmittance of the paper can be measured with
a photometer before and after filtering the air by
placing the clean filter disc and later, the exposed
filter disc  against the  photometer window and
noting  the intensity  of  light transmitted in  each
test.
From these measurements  the optical density of
the soiled filter paper can be computed in COHS.
The  COH is  an abbreviation for Coefficient of

        TVU.S. GOVERNMENT PRINTING OFFICE  1974: 624-971

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Haze and one COH unit represents an  optical
density of 0.01. The optical density of the  deposit
or soiling is the logarithm to the base 10 of the
ratio of the  intensity of light transmitted through
the clean filter paper to the intensity of the light
transmitted  through the  soiled filter  paper.  In
terms of percentage, it can also  be the ratio of
percent transmittance  through the  clean paper
(considered  as 100%)  to the  percent transmit-
tance through the soiled paper.
Therefore,
 I0        Iog10 100%
 It
 where,
 I0    =

 It    =

 %T  =
                %T

         average light intensity  transmitted
         through clean filter paper,
         light intensity transmitted through the
         soiled paper, and
         percent light  transmitted through the
         soiled paper when the light
         transmittance through clean paper is
         considered as  100%
Since Iog10 of 100 = 2.0, we have
     O.D. = 2.0 - log %T
By  definition, one COH unit equals  an optical
density  of  0.01.  Thus,  the number of  COHS
represented  by  the  actual  O.D.  found  equals
O.D./0.01 = 100  X (2.0 — log %T).
COH unit measurements are usually expressed as
COHS per 1,000 linear feet of air passed through
the filter paper. The concept of linear flow, upon
which  the  expression  COHS  per  1,000 feet  is
based,  considers that  through  each point on the
surface of the filter a long stream of air passes
leaving  its  load  of dirt particles deposited. One
might think of the sample  as a long column of
air  the  same diameter as   the  diameter  of the
exposed filter paper and with  a  volume equal to
the measured volume of the air sample.
Computations
1. Volume of air = R2 — RI (for dry or wet gas
meter),
  R2 = final reading in cubic feet
  R! = original reading in cubic feet
or, volume of air

     — ^ 1 "*"  *' (for rotameter or critical orifice)
             2
F! = initial flow rate in cubic feet per minute

F2 = final flow rate in cubic feet per minute
  t = sampling time in minutes

Corrections for Temperature and Pressure
The  value R2 — RI for the gas meter should be
corrected  for temperature and pressure according
to the Charles' and Boyles' laws.
Each F value for the rotameter or orifice should
first  be corrected to what  it would be  at the
standard temperature and pressure at which the
measuring device was calibrated:
                                                    2. Area = TT d2, where d is the inside diameter of
                                                               ""4"      the cylinder in feet
                                                         _             cm.     in.      ft.
                                                         Ft. = mm. X	X	X ^r—
                                                                      mm.    cm.     in.
                                                                          Volume
                                                    3. Linear feet of air = —	= L
                                                                           Area
                                                    4. COHS per 1000 feet
                                                                  = (2.0 - log %T) X 100
                                                                            L/1000
                                                                     (2.0 - log %T) X 100 X 100
                                                                     (2.0-log%T)Xl05
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