EPA-R1 73-004

March 1973           Environmental Health Effects Research Series
Research Study  to Determine
the Range of Carboxyhemoglobin
in  Various  Segments
of  the American Population

                           Office of Research and Monitoring
                           U.S. Environmental Protection Agency
                           Washington, D.C. 20460

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-------
                                           EPA-R1-73-004

   Research Study  to Determine

the  Range of Carboxyhemoglobin

          in  Various  Segments

    of the American  Population

                  Annual Report

        October 1, 1970 - September 30, 1971

                        by
                 Dr. Richard Stewart
            Department of Environmental Medicine
              Medical College of Wisconsin
                8700 West Wisconsin Avenue
                Milwaukee, Wisconsin 53226
                 Contract No. CPA 70-71
               Program Element No. 1A1007
          EPA Project Officer: John H. Knelson, M.D.

                Human Studies Laboratory
           National Environmental Research Center
         Research Triangle Park, North Carolina 27711
                    Prepared for

             OFFICE OF RESEARCH AND MONITORING
            U. S. ENVIRONMENTAL PROTECTION AGENCY
                 WASHINGTON, D.C.  20460

                     March 1973

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                                                            page 2.








the program has been well received and the goals for the first year of sampling





adequately attained.





        Samples collected from the Milwaukee area before the initiation of




the COHb Mass Screening Program have been combined with those of the  regu-





lar Milwaukee study to form a detailed written report  At this writing, data





from five other cities, New York,  Miami,  St. Louis,  Chicago and Washington,





D,  C.  have undergone preliminary computer analysis.  A manual analysis





of lab tabulated data has  also provided up-to-date information on non-smokers





for all of the sampling sites  and cities thus far visited.





        The extent and location of  sampling to be conducted over the final




year of the survey will be dictated somewhat by the results of the preliminary





analysis of segments now completed.  Additional samples needed  for  comple-





ting certain population segments for race,  sex, age,  etc. will require that




some cities be re-visited while an effort will also be made to increase the





sample size of groups having special occupations (e., g. ,  firemen,  taxi cab




drivers, housewives),  or other distinguishing characteristics (e.g.,  hospital





inpatients, newborn infants,  expectant mothers).

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                                                            page 3








                         II,  SAMPLING STATISTICS








        Fifteen separate sampling programs were conducted over a 12-month





 period between October, 1970  and October, 1971,  The totals  (Table I)  repre-





 sent 187 days  of sampling in 13 different cities.  Two sampling locations,





 Milwaukee and Detroit, were re-visited.  All  of the sampling programs were





 conducted with blood banks which were affiliated with the National Red Cross





 Blood  Bank Program,  and approximately two-thirds of the blood samples were





 collected on mobile units operated by the collection centers.  These mobiles





 were assigned to sampling sites  usually within a radius of 50 miles from the





 centers, which offered an excellent opportunity to sample donors near their





 natural home or work  environments.  Two  of the  blood banks,  New York City





 and Detroit,  operated  exclusively from mobile units,  while the blood bank at





 Anchorage was the only center where blood was drawn totally at the blood





 center.





       Through the efforts of contacts established in Anchorage,  additional





 samples have been collected from the Alaskan Eskimo and Indian segments,





neither of which are included in the regular Red Cross Blood Collection





Program.





       The  greatest number of samples  was collected from Denver (Z091) with





an average of 87 samples per day.   The  best daily yield of samples was ob-





tained  from New York  City,   186 samples per  day,  and Detroit  (148 samples





per day).  Including an additional 3, 900 blood samples  collected at the Milwaukee

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                                                           page 4,








County Outpatient Clinic,  and at other Milwaukee hospitals prior to October,





1970,  a grand total of 21,  314 samples were collected.





       Table I contains a  summary of the  sampling statistics  for the first





year of the sampling program.  In addition to the blood samples reported





in Table I a breath samples was collected  from every tenth blood donor and





an average of 2  ambient air samples were collected in the areas in which





the blood samples were being drawn.   These samples were also returned





to the Environmental Medicine  Laboratory where they were analyzed for CO.

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                TABLE I
Sampling Statistics  -  COHb Survey Year I
                                                       page  5,
City-
Milwaukee # 1
Chicago
Detroit #1
New York
City
13. C.
Miami
New Orleans
St. Louis
Milwaukee #2
Denver
Hawaii
San
Francis co
Seattle
Anchorage
Detroit #2
Starting
Date
10/12/70
117 4/70
11/20/70
127 7/70
I/ 4/71
1/25/71
2/17/71
37 9/71
3/20/71
4/19/71
67 1/71
6/28/71
7/19/71
87 9/71
9/28/71
TOTALS
Sample
Days
12
12
8
10
14
12
15
10

24
18
14
11
18
9
187
Blood Bank
442
271
0
0
119
471
509
31
0
1955
899
965
587
250
0
6,499
- Mobile
687
725
1184
1865
1494
425
42
1185
720
136
301
407
582
0
1163
10, 916
Previous Milwaukee Study
Total
1129
996
1184
1865
1613
896
551
1216
720
2091
1200
1372
1169
250
1163
17,415
3, 900
                                                 21, 314

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                                                           page 6,







               in.  MECHANICS OF THE SAMPLING PROGRAM








        Our blood sampling program has been well accepted by blood collec-




tion centers throughout the country.  Our field representatives have reported





that,  without exception, they have been welcomed warmly and enthusiasti-





cally at each blood center thus  far visited.





        At this  writing, only one blood center has been reluctant to partici-





pate in our  survey  on the grounds that they have  had several such requests





and that these tend to disrupt their  operation.  Since the center is a key





sampling site,  attempts to gain their confidence  and cooperation  will  be





continued.





        We believe  that the blood center sampling program is providing data





which is valid in representing daily "real life" exposures  to carbon monoxide.





Sampling at the blood centers is usually prompt (less than 15 minutes), and





since the normal half-life of COHb  is 4-5 hours,  COHb levels in  the donors





should still be  quite representative of CO exposures received in their  "natural1





environment.  This is especially true for samples collected on mobile units




since those blood drawings are conducted at  locations convenient to the





donor's residence or place of employment.





A.      Contacts:





               Our initial  contact with each of the blood collection centers





       was  made by a phone call to the Blood Bank Director or Adminis-





        trator followed by  a detailed written explanation of our  COHb Sam-





       pling Program.  All contacts with the Red Cross Blood Banks

-------
                                                                      page 7.








         were preceeded by a letter of introduction by Tibor J. Greenwalt,





         M. D.,  Medical  Director of the Blood Program of the American





         Red Cross,  In some instances,  a complete copy of the research





         protocol was requested for review by a blood center before final





         approval would be granted.





              All personal contacts and field sampling have been conduc-





         ted by our two traveling research associates,  Miss Leigh Platte





         and Miss Betty Stewart. They have been the key to establishing





         the efficient field sampling programs, and  in gaining the superb





         support and  excellent reputation  which we feel this program has





         enjoyed over the first year.







B.       Collection and Shipping:







              A trial period during which samples were analyzed at the





         blood collection  center  was initiated at  the  start of the Milwaukee




         survey.   This approach was abandoned  when it became evident that




         an adequate quality control program could not  be achieved,  and that





         the efficiency of sample collection would be greatly hampered.





         Therefore,  all blood samples  collected in the field have been re-





         turned to the Environmental Medicine Laboratory for analysis.





              Shipping of blood  and breath samples  has been exclusively





         via the  United States Mail  (primarily Air Mail).  Shipping cartons





         designed to hold up to 30 Vacutainer blood collection tubes,  or

-------
                                                    page 8,







12 breath tubes/carton are shipped in padded shipping envelopes.





Breakage has been negligible (less than 50 tubes to date), postage





costs are about $1. 50 per carton,  and the average shipping time




is 3-4 days.





       Blood samples are usually collected with assistance from





blood bank personnel.  The collection device is a purple-top 5 ml





Vacutainer tube containing liquid EDTA as the anticoagulant.   This





tube has  been especially convenient in centers where preliminary




blood samples are already drawn with a Vacutainer system.   In





many centers, however,  the donors are not sampled  previous  to





the blood drawing, in which case the sample is drained from the





collection tubing following the blood drawing.  While  the subject is




donating  his  blood he is asked to reply to the questions appearing




in the questionnaire shown in Figure 1.





       A breath sample is collected from every tenth donor to




establish the blood-breath relationship for CO under  field sampling





conditions.   Two ambient  CO samples are taken in breath collec-





tion tubes at each of  the sampling sites  at intervals  spaced to best





represent the ambient concentration of CO during  the blood drawing





period.

-------
                  MASS CARBOXYHEMOGLOBIX SLRVEY
Location:
                 City-
                                           Date:
Occupation:_
                                Com pant-
Coming From:

Name:	

Age:	
                             How Long Ago:
            Sex:
     RACE
  1.
  Z.
  3.
  4.
  5.
  6.
  7.
Caucasian
Negro
Asian
Mexican
Am. Indian
Hawaiian
Other
    SMOKE
1.
Z.
3.
4.
No
Cigarettes
Cigar
Pipe
 INHALE
                Height:
                            HEALTH
1.
Z.
3.
4.
5.
6.
7.
Good
Blood Dis ease
Lung Disease
Heart Disease
Kidney Disease
Liver Disease
Other
                  QUANTITY/DAY
                1.   packs
                                   Collection
                                   Time:
                                                                    minutes
                                             Zip
                                Weight:
                                             OCCUPATION
1.
->
3.
4.
5 .
6.
7.
Urban

Suburban

Rural

Unemployed
In
Out
In
Out
In
Out

                             LAST SMOKED
                              •< 1  hour
                              1 hour
                              Z- 3 hours
                              4-7 hours
                              8-15 hours
                              1 o- 24 hours
                              ^Z4 hours
                                              Interviewer
%Sat.
Carboxyhemoglobin

gm%
Hemoglobin



ppm
Background CO

mm Hg
Barometric Pressure



Date:
Analyst:

CO- Oximeter

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                                                           page 10.







            IV,  ANALYSIS OF CO IN BLOOD, BREATH AND AIR










A.     Gas Chromatographic Analysis of CO:





              The use of gas chromatography (GC)  for analyzing low levels





       of CO in air has lagged somewhat behind infrared techniques.





       Although it is not  difficult to separate CO from other atomospheric





       gases by gas chromatography,  it is difficult  to detect CO at ambient





       or normal breath  levels using conventional GC detectors.   The GC





       principle,  however, offers the advantage of low sample volume for





       rapid single sample determinations.  The one gas chromatographic





       detector exquisitively sensitive to CO is the  helium ionization sys-





       tem,  which was successfully used during the early stages of the





       mass screening program.




              A  search of the literature revealed the existence of a more




       simple and unique system which incorporates the use of a nickel





       catalyst to convert CO to methane which can then be detected at low




       concentrations by a conventional hydrogen flame ionization detector





       (Figure 2). Operating conditions have been optimized to provide





       an elution  time  of about 3 minutes.  The limit of detection for CO





       at the conditions described in  Figure 3 is about 0. 3 ppm.





              Standards  against which the gas chromatograph are cali-





       brated are prepared by injecting a measured quantity of CO into a





       Saran bag  which contains a known volume of  air measured by a

-------
                 FIGURE 2
                                 page 11.
c/2
c/)

§2

  h-
  N
^
U-
O


UJ
§<

!5i
O
<
o

-------
±L
 H

CO ANALYSIS by H2 FLAME

 Column - 61/2' x 1/8" stainless
 Packing • molecular sieve 5A
         60/80
 Column temp. - IOO°C
         Catalyst temp.-285° C
 Injector-150° C Detector* 260°
 Carrier gas- Helium
                                                   page 12.
                                    '.ILL
                                     1-t
    FIGURE 3


 Gas Chromatographic

Tracing of CO Standards

     in Air
     X attenuated to x 2
     SAMPLE SIZE - 0. 5 ml

-------
                                                           page 13.







       "Precision"  Wet Test Meter.  The  standards  are very stable, since





       Saran  is extremely impermeable to carbon monoxide.  To insure





       the removal  of trace quantities of CO, air used in the preparation





       of standards is passed through a Gas  Mask Canister  MSA Type N,





       Model SW, containing a Hopcalite catalyst which oxidizes the Co





       to CO2.







B.     COHb  by Gas Chromatography:




              The gas chromatographic system used for the analysis of





       breath and ambient air samples  is  also useful for the determina-





       tion of COHb.  The method involves the release of CO from its





       hemoglobin bound state with a small quantity  of concentrated sulfuric





       acid.  The reaction is  carried out in  a tightly closed reaction vessel





       of known volume so that the gaseous contents  of the vessel  containing





       the CO released  can be analyzed for CO content and the percent




       COHb  then calculated.







C.     The LL CO-Oximeter Model 182;




              Instrumentation Laboratories', Inc.  CO-Oximeter Model  18Z





       provides one with a rapid  and precise means  of analyzing for COHb,





       O2Hb,  and Hb in one simple operation,  with a cycle time of approxi-





       mately 1 minute/sample.  With the CO-Oximeter it is possible to





       analyze up to about 200 field  samples in one eight-hour work shift

-------
                                                    page 14.


(not including the additional samples which must be run to maintain

quality control in the operation).

       One of the disadvantages in using this instrument, however, is

that it must be calibrated against a known standard of human blood.

The gas chromatographic method for determining  CO in blood pro-

vides the analyst with an absolute method of analysis  needed for the

standardization of blood samples which can then be used to calibrate

the CO-Oximeter 182.  Quality control is maintained  by:  (a) daily

calibration of the instrument against "carry-over" blood, standard-

ized by  the independent gas chromatographic method; (b) daily

calibration against blood standards which have been specially pre-

pared, standardized, and stored at freezer temperature;  and  (c)

comparison of readings  for every tenth sample on two IL  CO-

Oximeter instruments which are always calibrated and in operation

to insure perfect agreement.

       Studies conducted to determine the reproducibility of values

on the CO-Oximeter show that values  for  COHb are repeatable

within a 0. 2 unit spread (_t 0. 1% COHb) when the same blood sample

is undergoing repeated analysis at one sitting.  Readings  taken over

a period of several days are not as precise, e. g. , ten readings

taken over a period of sixteen  days using  the same machine produced

a spread of 0. 6% Hb and 0.4%  COHb.  Actual mean and standard

deviations were:

                   Hgb%      15.2±0.19
                   COHb%      1.2±0.13

-------
                                                            page 15.


                   V.  STATISTICAL ANALYSIS OF DATA



A.     Variables Studied:

               A total statistical analysis for the cities sampled during the

       first year of the COHb Study is being prepared by A. A. Rimm, Ph.D.

       and his assistants at the Department of Biostatistics of the Medical

       College of Wisconsin.  At this writing, a detailed statistical report

       has been prepared by the Department of Biostatistics covering  data

       for the Milwaukee area.   Preliminary  computer analysis has also

       been prepared from data  obtained from Miami, Chicago,  New York,

       St. Louis and Washington, D. C.  Data from other cities are in various

       stages  of being processed.  Following  is a list and a description of

       the variables studied  in the preliminary analysis of the data:

                      Variable                       Description

               Age, height, weight,  sex

               Race                           White, Black, Asian, Mexican,
                                              Am. Indian, Hawaiian, other

               Health                          Healthy:  diseases; blood, lung,
                                              heart,  kidney, liver,  other

               Occupation                     23 major categories

               Occupation Location            Urban In, Urban Out,  etc.  (see
                                             questionnaire)

               Where  Coming From          Home,  work, other

               Items Smoked                 None, cigarettes, cigar,  pipe,
                                              combination

-------
                                                              page 16
          Variable





      Inhale





      Packs /Day-





      Hours Ago Last Smoked





      Background CO Level





      Barometric Pressure





      Carboxyhemoglobin Level





      Hemoglobin





      Sample Time
        Des cnption





Yes/No





0 3 packs increments





7 levels (see questionnaire)





To the nearest 1 ppm





During Sampling





To the nearest 0. 1%





To the nearest 0, i gm%





Hour of Day
      Other variables, such as meteorological conditions and air





pollution levels,  will  be worked into the study whenever information





is available.  Breath-blood data is being analyzed separately.





      Some generalizations drawn irom the computation lab's analysis





of COHb data follow:





      1.   Data Description:





          The distribution of  COHb levels is clearly not "normal".





      Rather, it  is skewed to  the right due to the great impact of





      tobacco smoking on COHb levels  By  comparison,  the hemo-





      globin levels do produce a normal curve,  This would  suggest





      at this point at least that hemoglobin levels are not associated





      wit.b COHb smoking interrelationships,





      ?,.   Factors Associated with COHb Levels;
          Assuming that the study constitutes a random sampling

-------
                                                         page 17,








 of the population^  some of the factors associated with COHb





 levels can be studied without fear of bias,.  That assumption





 is made for the following remarks.





     All data collected thus far shows quite clearly that  cigar-





 ette smokers have a significantly higher COHb level  than non-





 srnokers.   The following data from  the Milwaukee study also





 shows that  the standard deviation for COHb in non-smokers is





 about 1/3 that for  smokers.   This is expected because of the





 variability  of smoking habits





                          Non-Smokers       Smokers
N
X
cf
SEM
2798
1, 33
0, 85
0. 02
1620
4047
2, 52
0 06
     The trend of COHb levels with increasing cigarette con-





sumption for the Milwaukee Study is  shown in Figure 4,  This





figure illustrates the great influence of cigarette smoking





while it also suggests that a  "COHb saturation"  level does





exist0  For Milwaukee smokers, this level appears  to be near





1,5 packs/day.





    As might be expected from each cigarette level, in-





halers had a significantly higher COHb than non- inhalers ,





Time from the last  cigarette smoked to the drawing of  the





sample is shown to  be related in Figure 5,   The precipitous

-------
                                                                     page  18.
COHb



Levels
             2-
             1 '
                                                N= 142
FIGURE  4
                                                                        N = 30
                                           COHb Levels for Varying Amounts


                                                         of


                                             Cigarettes Smoked per Day



                                                  (Milwaukee Study)
                     N = 2798
                                1
                                        1
5tol     1
                                                1.5
   ~r

    2
2.5
               non-smokers
                                    _,   .    . _.
                                    Packs of Cigarettes Smoked per Day

-------
COHb

Levels
            7-
            6-
            5 -
            4-
            3 -
                                                                       page 19.
                                              FIGURE 5
COHb Levels for Varying Amounts o£ Cigarettes


     Smoked per Day and Time Since Last


                  Cigarette * •






   1.5 packs
                                                1 pack
                                              5 to 1 pack
                                                                   < . 5 pack
                i  i    i      I             *                    I
              <1  1   2-3    4-7         8-15                16-24


                                 Hours Since Last Cigarette Smoked


    *Groups of fewer than 15 people were not plotted.
                                                  >24

-------
                                                           page 20,







               drop in the more elevated COHb levels followed by a more





               gradual decline in the slope is  characteristic of the half-life





               decay phenomenon exhibited by COHb circulating in the blood





               stream.





                    Mean COHb levels of cigar and pipe smokers  is  signifi-





               cantly lower than cigarette smokers.  However, some of the





               highest COHb levels measured (up to 20% COHb) have been on





               cigar smokers who inhale.  This presumably is due to the




               higher  concentration of CO in cigar smoke.







B.     Summary of Milwaukee Analysis:





               Some of the relationships established were unmistakable and





       predictable, while others at this point are merely suggestive.  Fol-





       lowing are some of the basic conclusions  derived from the  study of





       the Milwaukee data:





       1.      Of all the variables studied,  cigarette smoking has  the




               greatest effect on COHb  level;





       2.      Because smoking has such an overwhelming effect on COHb





               levels,  most relationships can only be studied using samples





               from non-smokers.  Based on  non-smokers:





               a.    COHb levels as compared to  age, weight and





                    residence location show no significant trends;





               b.    Significant differences  in COHb levels were found





                    for certain  groups of sex, race and health status;

-------
                                                              page 21,







           however;  these differences were small and comments





           will be reserved until a broader and more complete





           sampling  is obtained;





       c.   Hemoglobin levels for males were significantly higher





           than for females; however, no relationship between





           hemoglobin values and smoking is  suggested,





 3.     In the non-smoking group, the strongest variables which result





       from the multivariate analysis of data were time of day, weight;





       and hemoglobin,.  However, these  only  explain  1% of the varia-





       bility of COHb levels,, while for cigarette smokers  the number





       of packs smoked per day accounts for over 30% of the variability





       of COHb levels,,





 4,,     Repeatability of measurement of COHb on the  same subject





       (this resulted from repeat samplings conducted in the Milwaukee





       survey) showed that even though there was  a significant differ-




       ence between normal non-smokers,  most of the variation is




       associated with differences between measurements on different





      days,   In other words,, the day-to-day differences on one person





      are larger than the differences in measurements between people.








COHb  Means from Hand  Tabulated Data:





      While the results of questionnaire data  and  analytical results are





being processed for computer analysis3  mean carboxyhemoglobin data





for non-smokers have been tabulated manually for each sampling site

-------
                                                            page 22.







       within each city,  and a combined weighted mean for  each city is pre-





       sented in Table II.





              Standard "t"  and F tests were used for comparing the COHb





       mean and Standard Deviations for the 15 sampling locations.  In Table





       II the cities are listed in ascending order, with respect to their mean





       COHb levels.  Pairs, or groups underlined are not significantly different





       from each other at the 95% Confidence Level.  However,  each of these





       groups or  individual mean values (not underlined) varies significantly




       from all other values in the table for either the "t" or F test.





              Mean  carboxyhemoglobin values usually varied as widely





       between  individual sampling sites or groups within each  city as they





       did between cities.   This  was  because samples from people in downtown





       locations and airports had consistently higher COHb levels than house-





       wives and  rural inhabitants.   COHb levels are also affected by occupation.





       For example,  the higher mean COHb level in the  second Milwaukee




       study is  due to high values from a large sampling of Milwaukee firemen.





       Taxi cab drivers  and traffic policemen similarly  often have COHb's





       over 2%.  This is an example  of the interdependency of variables





       which will need to be defined by expert analysis of the massive quan-





       tities of  data  generated by this study.








D.     Relationship Between COHb and Breath CO:




              Breath analysis is gaining in popularity and usefulness as a method





       of assessing the total body burden of a volatile substance which appears

-------
                        r—
                        LO
                                        -t
                                        r—
                                                 Denver
                                                                      page 23.
                                CO

                                00
                                                 Chicago
         c
         o
         0)
         p
 nj
T3
 C
 n)
=a


 K)
 0)
o
o
xD
                               oo
                               LO
                               00




                               O
                               in


                               O
CO
LH


O
                                                 Alaska
                                                 New Orleans
                                                 San Francisco
                                                 Detroit ?
                                                 Seattle
                                                                     o
                                                                     nj
                                                                     11

                                                                     0)
                                                                     >
                                                                     O
                                                                     .2 ^
                                                                     nj  0)
W
O
O

ao
a

nj
a

s
o
U

ra

H
•a
c
ai
-a

n)
                        OJ
                        ro
                               o
                               co
              O
                       X
                       ro
                               vO

                               o
                                        Milwaukee -2
                                                 Hawaii
                                                New York
                                                St. Louis
                                                D.  C.
                                        Mian-, i
                                                                               U
                                                      .  ^

                                                      -g 53
                                                      c IS
                                                      nj 4:
                                                                             c  2
                                                                             rd  "
                                                                             O i
                                                                             O -e
                                                                             U
                                                Detroit =--2
                                       o
                                       -o
                                                Milwaukee  ~
                                 O
                                 U     p

-------
                                                              page 24,







in the bloodstream.  Furthermore,  if one can analyze the breath for





the volatile substance at various intervals following an exposure to a





known concentration of that substance,  a breath decay curve can be





established. One then has an index against which he can make com-





parisons and estimate with reasonable  accuracy the time weighted





average exposure to the substance.




      The concentration of CO in the breath is truly representative of





COHb levels in the blood., and  COHb levels therefore can be equated





to an exposure level  for any estimated exposure time  to arrive at a





"time weighted average exposure concentration".





      Variations  in the collection technique and  in the  quality of the





device used for the collection allow for broad variations in breath





analysis results.  Therefore,  CO in its more permanent COHb form




is still a more reliable,, though less accessible,  means of determining





CO content  of the blood.





      The equation derived to best describe the  relationship between





CO in the  breath  and  % COHb of the blood is:







                          Y = 4X -  1.  9





      where:





                   Y  =  CO (ppm) in the alveolar breath





                   X  =  percent COHb in the blood





      This equation was derived from 341 data pairs in which COHb





was analyzed by  CO-Oximeter  and the  corresponding breath CO





concentrations were analyzed by either gas  chromatography or by

-------
                                                     page 25








 infrared spectrophotometry,,  These 341  data points are based on sam-





 ples collected from volunteers of human  exposure experiments who





 were trained and considered adept at collecting samples of their own





 breath.  The samples were collected in glass breath tubes  identical  to





 those used in our present survey.





        Since the initiation of the Mass  Carboxyhemoglobin  Screening





 Program,  an additional I, 000 breath samples have been collected in





 the field,  along with corresponding blood samples.  Figure 6 describes





 and compares the two groups  of data just discussed.  The curve for





 field collected samples represents all  samples, i.e., no attempt was





 made to screen out obvious leakers and no allowance was made for loss





 of CO from the tubes in transit,   (Although laboratory investigations





 show this loss is almost negligible, )





        As expected,  breath samples corresponding  to any given blood





 COHb level produce lower CO levels on the average for field collected





 samples.  Comparison of correlation coefficients  (also listed  in Figure





 6) indicates the much broader scatter of  data obtained by field sampling,





However,  regardless of this scatter, the field  data curve was well





defined  with less than 400 samples (as  described by the curve presented





at our first Review Meeting in March,  19,71).





        In summary,  although it appears  to be extremely risky to





attempt an assessment of CO exposure  on the basis  of individual sam-





ples,  it seems reasonable to conclude that breath  analysis on a mass





sampling basis might be a useful and reliable index of exposure to CO.

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                                                                           page  26,
                             FIGURE 6
       35-1
       30-
       25-1
Breath

 CO

 ppm

 (GC)
20-1
       15
       io-t
        5-1
        Breath CO and Corresponding COHb Values

                         for
            Field and Lab Collected Samples
                               (A) Lab Data
                               N = 341
                                                           (B) Field Data
                                                           N = 1025
                                                (A)  y = 4.6x - 1.9
                                                       R = 0.904

                                                (B)  y = 2.26x+ 0.69
                                                       R = 0.764

                                                    x = % COHb
                                                    y = ppm CO
                                                                   To"
                                                                        12
                                       % COHb (CO-Oximeter)

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                                                                           page 27.
                              VI.   YEAR TWO











       In Year Two the emphasis will be  for continued effort in fulfilling the





following requirements:








       1.    Conduct the sampling programs in Los Angeles and Salt





             Lake City;





       2.    Fill the  required 'sample  cells" for sex,  race, age, etc.,





             as described  in the Mass Screening Protocol for as many





             of the cities  already visited  as time will allow;





       3.    Attempt to sample as many ''special groups" as possible





             (including occupational groups,  newborn infants, expectant





             mothers, hospital inpatients, etc.);





       4.    Obtain a truly rural sampling population;





       5.    Complete laboratory investigations as outlined in the Pro-





             tocol to establish:





             a.    COHb levels arising  solely from endogenous





                   production of CO; and





             b.    Immediate effects of smoking upon COHb level





       6.    Continue and finalize the computer data  analysis relating





             COHb and the variables studied.






                                                  •& U. S. GOVERNMENT PRINTING OFFICE. 1973	746769/4170

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BIBLIOGRAPHIC DATA
SHEET
1. Report No.
 EPA-R1-73-004
3. Recipient's Accession Xo.
4. Title and Subcitle
   Research Study  to Determine  the Range  of Carboxyhemoglobin
   in Various Segments of the  American Population
                                                 5. Report Date
                                                   September 30,  1971
                                                                      6.
7. Author(s)
                                                 8. Performing Organization Rep'
                                                   No.
9. Performing Organization Name and Address

   Medical College  of Wisconsin
   Department of  Environmental Medicine
                                                 10. Project/Task/U'ork Unit N'o.
                                                                            CPA 70-71
12. Sponsoring Organization Name and Address
   Coordinating Research Council, 30 Rockefeller Plaza,  New York
    N.  Y.   10020     and    ENVIRONMENTAL  PROTECTION  AGENCY,
   Research Triangle Park, North Carolina   27711
                                                 13. Type of Report & Period
                                                    Covered
                                                                       14.
15. Supplementary Notes  project yiO.  QRC APRAC  CAPM- 8-68
                         MCOW-ENVM-COHb-71-1
16. Abstracts
    Approximately 17,500  blood samples  and over  1,000 breath  samples were  collected
    from blood  donors at  13 major sampling locations throughout the nation.   Two of
    these locations were  re-visited,  so that a total of 15 separate sampling programs
    were conducted.  Eighteen variables were statistically analyzed, including race,
    sex, age, occupation,  smoking habits,  etc.
17. Key Words and Document Analysis,  17o. Descriptors
    Air pollution
    Carbon monoxide
    Hemoglobins
    Blood gas  analysis
    Respiration
    Statistical analysis
    Ethnic groups
    Males
    Females

17b. Identifiers/Open-Ended Terms
          Age
          Personnel
          Smoking
          Environmental surveys
          Health
          Diurnal variations
17c. COSATI Field/Group
18. A\ ailabilicy Statement

               Unlimited
                                     19. Security Class (This
                                        Report)
                                                   U:D
                                                          20. 
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      proper authorized terms that identify the major concept of the research and are sufficiently  specific and precise  to be used
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FORM  NTIS-35  (REV. 3-72)                                                                                   USCOMM-DC 14052-P72

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