Document Display

Initiate a new search within the currently selected document
Show document key fields and properties
Include current hits
Describe the error you saw:
E-mail Address (Highly Recommended)
When you have finished entering your information, click the Submit Error button.

Page 1 of 52 Previous Page or group of Pages Previous Occurence of Search Term Reload with a larger image Reload with a smaller image

<pubnumber>AP45</pubnumber>
<title>Thanksgiving 1966 Air Pollution Episode In The Eastern United States</title>
<pages>52</pages>
<pubyear>1968</pubyear>
<provider>NEPIS</provider>
<access>online</access>
<operator>LAI</operator>
<scandate>20061204</scandate>
<origin>hardcopy</origin>
<type>single page tiff</type>
<keyword>air november pollution figure levels philadelphia episode surface day new weather york afternoon wind dioxide thurs pollutants level washington mixing</keyword>
<author>Fensterstock, Jack C. Fankhauser, Robert K.  United States. National Air Pollution Control Administration. ; United States. National Air Pollution Control Administration.</author>
<publisher>U.S. Dept. of Health, Education and Welfare,</publisher>
<subject> Air Pollution--United States ; Weather</subject>
<abstract></abstract>

          THANKSGIVING  1966
        AIR POLLUTION EPISODE
   IN THE  EASTERN  UNITED STATES
             Jack C. Fensterstock
       Air Quality and Emission Data Program

                     and
             Robert K. Fankhauser

              Meteorology Program
  U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Consumer Protection and Environmental Health Service
   National Air Pollution Control Administration
            Durham, North Carolina
                  July 1968
 image: 








The AP series of reports is issued by the National Air Pollution  Control
Administration to report the results of scientific and engineering
studies, and information of general interest in the field of air  pollu-
tion.  Information reported in this series includes coverage of NAPCA
intramural activities and of cooperative studies conducted  in  conjunc-
tion with state and local agencies, research institutes, and industrial
organizations.  Copies of AP reports may be obtained upon request, as
supplies permit, from the Office of Technical Information and  Publica-
tions, National Air Pollution Control Administration, U.S.  Department of
Health, Education, and Welfare, Ballston Center Tower No. 2, 801  North
Randolph Street, Arlington, Virginia  22203.
       National Air Pollution Control Administration Publication No. AP-45
 image: 








                        ACKNOWLEDGMENTS

       The Public  Health Service acknowledges with appreciation the many
contributions of cooperating agencies in the publication of this report, and,
in particular, the data provided  by  the following statewide and local sampling
networks.
       STATEWIDE:  Connecticut, Maryland,  Massachusetts,  New  Jersey,
New York, Pennsylvania, West Virginia.
       LOCAL:  Allegheny County, Pennsylvania;  Chattanooga, Tennessee;
Jefferson County, Alabama;   New York,  New York;   Philadelphia,  Pennsyl-
vania;   Washington,  D.C.;   Worcester, Massachusetts.
 image: 








 image: 








                             CONTENTS
INTRODUCTI ON 	   1
NARRATIVE OF EPISODE'S METEOROLOGY 	   3
AIR QUALITY  	  17
       Gaseous Pollutants  	  17
       Particulate  Pollutants 	  29
SUMMARY  AND  CONCLUSIONS  	  35
APPENDIX: METEOROLOGY AND DISPERSION OF AIR CONTAMINANTS	  37
REFERENCES  	  1»3
SELECTED BIBLIOGRAPHY 	  45
 image: 








 image: 








                      THANKSGIVING  1966
                    AIR POLLUTION  EPISODE
              IN  THE  EASTERN  UNITED  STATES

                             INTRODUCTION
       In recent years adverse health effects resulting from  acute air pollu-
tion episodes have been dramatically demonstrated.  In these cases excess  ill-
ness due  to sharp increases in air  pollution concentrations was sudden  in onset
and  in some cases  fatal in outcome.  The best  known  cases are  those  in the
Meuse Valley, Belgium1  (1930);   Donora, Pennsylvania2 (1948);  London '
(1952 and  1953);   New York  City5 (1953);   London6 (1962); and New York
City  (1963).   Excess  deaths over normal expectancy ranged from 17 in Donora
to 4000 in the 1952 London smog.  Sensational and tragic as these acute epi-
sodes are,  health authorities  are even more  concerned today with the  slow,
insidious  effects on human lungs and other organs by air pollution levels  that
are much  lower, but are  continued every day,  year after year.
       The weather is  a  major factor  in the  creation of air pollution problems.
When air  pollution episodes occur, they result not so much  because of a  great
or sudden increase in the output of pollutants,  but rather because of adverse
weather conditions, which trap the pollutants in a  mass of stagnant air.  Even
during normal  weather  conditions,  the daily accumulation of wastes in a com-
munity's air varies with weather factors  as well as  with the rate  at which  pol-
lutants are discharged  into the atmosphere.   Air pollution has become  a  ubiq-
uitous threat to our health and welfare because of  the ever-increasing emissions
of air contaminants into the never-increasing atmosphere.   The result is an  in-
creased exposure of large  segments of the  population.
       Meteorologists of  the Air Resources Cincinnati Laboratory  (Environmental
Science Services Administration) at the National  Center for Air  Pollution Con-
trol  issues advisories* or  forecasts  of extended periods  of restricted  natural  ven-
tilation,  i.e.,  atmospheric stagnation.   This  report documents one such fore-
casted  stagnation period which occurred in  the  Eastern United States during late
November 1966.  During  the stagnation period, air quality  deteriorated signifi-
cantly.  An analysis of air quality data from a number of cities  showed elevated
*Forecasts are issued at the National Meteorological  Center
 in Suitland, Maryland.
 image: 








levels  of  selected  pollutants for the  week  preceding the episode even though
an advisory was  not issued,  because the area affected did not fit  the criteria
for extent and duration concurrently.
        This publication documents the Thanksgiving 1966 Air Pollution Episode
in the Eastern United States in terms of daily  meteorology and ambient air
quality for  the weeks immediately before,  during, and  after the episode.
        The first  section presents the episode's  meteorology in a technical  de-
scription  of the development,  progress, and breakup of the stagnating  high
that  caused the episode.   A more general  discussion of meteorological factors
that  act to disperse, or not to disperse, the various pollutants that contaminate
the atmosphere  is  included  in  an  appendix.
        The section on  air quality describes the sources and  possible health
effects of the air  contaminants.   The actual day-by-day  levels of the various
pollutants are presented graphically  and daily  meteorology is correlated  with
the pollutant  concentrations.
 image: 








           NARRATIVE  OF  EPISODE'S  METEOROLOGY
       Occasionally a  high-pressure  system  becomes almost motionless  over
some part of the United States and tends to interrupt the usual  cycle  of ven-
tilation.   As a  consequence,  the usual  daily afternoon dispersion and dilution
(see  appendix for  a  general discussion of these terms)  are  diminished, and  pol-
lutants may accumulate to high concentrations over a  period of several  days.
       This section of the report  describes  one such stagnating  high,  which
caused the Thanksgiving 1966 Episode.  The development, progress, and break-
up of this  system are documented on a day-to-day basis.
       On November 20,  a surface  high-pressure  area,  which had been moving
steadily eastward across the United States,  was centered over New York State
(Figure  1).   This high was  classed as "cold" since,  at upper  levels* the tem-
perature was relatively  low compared to temperatures of surrounding air.   Fig-
ure 1 shows that over New York  State the temperature at the 500-millibar (mb)
level was -25 C.   The same  chart shows that an  intrusion of 10 C warmer air
appeared over the north-central states.   The wind pattern carried this warmer
air eastward.   The replacement of the cold air over the surface high by warm
air was largely  responsible  for the ensuing  high-air-pollution-potential episode.
       On November 21  (Figure 2),  the center  of the surface high moved on
into  upper New England.   This area of light winds, i.e. ,  poor  horizontal ven-
tilation,  became elongated from  northeast to southwest.   In response to the sea
level isobaric pattern,  surface winds  were  blowing clockwise  around  the center
of the high with moderate northeasterly winds along the eastern  seaboard and
strong southwesterly  winds  over  the upper Great Lakes region.   At the  500-mb
level the  warmer air had moved  eastward from the north-central states to a posi-
tion  over  the Great Lakes.
       On November 22  (Figure 3),  the surface high  remained  in the same gen-
eral  location, although it continued  to  elongate to the  northeast and southwest.
*Weather charts are prepared twice daily showing wind direction and
 speed,  temperature, and  height of the level aloft, where  the  air
 pressure  is 500 millibars.   The approximate  height  of this  level  is
 18,000 feet.
    318-501 O - 68 - 2
 image: 








      Figure 1A.   Surface weather map, Sunday,'November 20, 1966.
Figure IB.  Upper level  (500 mb) weather map,  Sunday,  November 20,  1966.
 image: 








      Figure  2A.  Surface weat-her map,  Monday, November 21, 1966.
Figure 2B.  Upper level (500 mb) weather map,  Monday,  November 21, 1966.
 image: 








      Figure 3A.   Surface weather map,  Tuesday,  November 22, 1966.
Figure 3B.   Upper  level (500 mb) weather  map, Tuesday,  November  22,  1966.
 image: 








It extended along the Atlantic seaboard from Newfoundland to Virginia.   At
the 500-mb level over New England  and southward, the air temperature  had
warmed to above  -20 C.   The spread of this warm  air aloft began to cause
restriction of  vertical dispersion.
        On  November 23 (Figure  4),  continued  elongation of the surface  high
resulted  in  two high-pressure centers,  which were connected  by a ridge across
New  England.  On the west side of  the elongated  high,  moderate southwester-
ly winds  occurred ahead of an advancing cold front.   At the  500-mb level
(Figure 4) the warm  temperatures continued to spread  east and  south.   The
warming of air at the upper levels had, by  November 23, caused the reclassi-
fication  of  the high  to  "warm."   Ventilation in the vertical  direction was  re-
stricted by  this upper-level warming.
        These  meteorological conditions occur often, but are usually followed
by the  passage of a  cold front with accompanying brisk winds  and an influx of
cleaner air.   In  the  November 1966  case the forecast indicated that the cold
front  approaching from the  west would  be delayed,  and an advisory of high air
pollution potential was  issued  for areas A and B in Figure 5.
        On  November 24,  Thanksgiving  Day (Figure 6), the two surface highs,
one east  of Newfoundland  and the other over northern Georgia and Alabama,
were  still  joined by  a  ridge of high pressure across New  England.   The cold
front  moving  across southern Canada had stalled along the St.   Lawrence  Valley,
but a wave on this front was  developing in  the vicinity of Iowa.   With the ex-
pected approach  of the  Iowa disturbance, it appeared  that the western part of
the forecast area  (A  in  Figure  5)  would have better ventilation,  and the adviso-
ry for area A was discontinued.   However,  because of the development of the
high to the south, the advisory of high air pollution potential  was extended in
that  direction to include area C  (Figure 5).
        On  November 25 the surface  high over  the  Southeast had  moved to near
New  Orleans  (Figure  7).   The frontal wave  over  Iowa developed  rapidly and
was moving over the  Great Lakes.   The ridge  over  New England  was being dis-
placed seaward.  At  500 mb, colder air had returned to the Great Lakes  region.
With  the  projected eastward movement  of the Great Lakes storm,  and the  move-
ment  of  the clean air behind  it to the  east and south,  the advisories for the re-
maining  areas, B and C, were discontinued as of 7:00 p.m.  E.S.T.
       On November 26 (Figure  8) the  cold front,  which had  moved through
the Great Lakes  region  the  previous day, passed off-shore  into the Atlantic.
The weather map again  showed a high over the New  England  states extending
southward, but the high could not  be considered as stagnant because it had
 image: 








    Figure 4A.   Surface weather map,  Wednesday, November 23,  1966.
Figure 4B.  Upper level (500 mb) weather map, Wednesday,  November 23,  1966.
 image: 








                             ADVISORY NUMBER 73

       Begin high air pollution potential for Areas *A and B, 1ZOO EST November Z3,  1966
       Begin high air pollution potential for Area C, 1200  EST, November 24,  1966

       End high air pollution potential for Area A,  1300 EST,  November 24, 1966.
       End high air pollution potential for Areas B and C,  1900 EST, November 25, 1966

       Sent with Advisory Message of 1ZZO EST, November 25,  1966  Although atmospheric
             dispersion will improve this afternoon, the pollution that has accumulated
             in east coast cities will be dispersed gradually until a cold front passes
             during the night.
Figure 5.  High-air-pollution-potential  forecast areas,  November 23 -  25,  1966.
 image: 








     Figure 6A.   Surface weather map,  Thursday, November 24, 1966.
   Figure 68.  Upper level (500 mb) weather map, Thursday, November 24, 1966.
10
 image: 








     Figure 7A.   Surface weather map,  Friday,  November  25,  1966.
Figure 78.  Upper level (500 mb) weather map, Friday, November 25, 1966.
                                                                      11
    318-501 O - 68 - 3
 image: 








       Figure 8A.   Surface weather map, Saturday,  November  26,  1966.
  Figure 8B.  Upper level (500 mb) weather map,  Saturday, November 26, 1966.
12
 image: 








just  formed and extensive storm systems  to  the west  threatened  its continued
existence.  The  high that had been over New Orleans had  been displaced off-
shore to the southeast so that it,  too,  presented no threat of high  air pollution
potential.
        Table  1  presents meteorological data of selected cities during the period
from  November 13 through November  30.   The  data shown  include the average
daily temperature, which  is computed as the mean of the  daily  maximum and
minimum temperatures.  The  cloud-cover column shows the average observed
daytime  cloud cover estimated to  tenths.   The afternoon mixing depth is  an es-
timate of the height to which  convective currents rise  during the most active
period in the afternoon.   These estimates are  made  using upper  air temperature
data  obtained by radiosonde  observations.   Since  upper air  data are not avail-
able  in the immediate vicinity of Birmingham,  Boston,  and  Philadelphia,   the
general pattern of the mixing depths was analyzed and extrapolated values were
assigned.   At Washington, D.C., the upper air data were obtained at  Dulles
Airport and were  used with  surface  temperatures from Washington National  Air-
port.  The  average wind speed  is the average of  the speed  at each thousand
feet, including the surface,  up to the  height  of the afternoon mixing depth.
The  column labeled  "Ventilation"  is the product of  the afternoon mixing  depth
and  the average  wind speed,  and is considered  as the  flow  through a column  1
meter wide.  The  resultant wind direction  is the vector sum of eight surface
wind observations spaced through a  24-hour period.   It indicates  the direction
of displacement of the surface  air in the vicinity of the designated city.   The
average surface wind speed  is  the average  of  8 hourly observations per day at
3-hour  intervals.
        These  parameters are  correlated with air quality data in  the next  section
of this  report, to show how adverse meteorological conditions permitted the  con-
centrations  of air pollutants to reach high  levels.
                                                                             13
 image: 








  Table  1.  METEOROLOGICAL DATA  FOR SELECTED CITIES DURING
           NOVEMBER 1966 AIR POLLUTION  EPISODE
THE
Pittsburgh,  Pennsylvania (Greater Pittsburgh Airport)
Date
Nov.


















13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Birmingham,
Nov.

















13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
1 .
38
40
36
42
53
52
34
32
39
39
45
51
53
44
56
38
28
30
Alabama
55
56
55
54
63
63
60
55
54
51
53
55
58
65
54
43
41
43
o
u^^
3 *-
— S
2
0
4
8
9
9
7
2
0
5
8
9
10
7
10
10
10
10
(Municipal
4
2
2
0
3
3
4
3
10
6
2
3
6
10
10
2
0
3
Afternoon
mixing depths
(meters)
974
795
8T6
474
904
242
1217
837
1019
638
769
379
303
890
M
b
697
501
Airport)
600
1150
M
1330
500
1600
1250
850
850
750
1000
900
1100
900
350
1500
1500
M
~i •-
^^'i
P-o §>-c
« S ° a.
3.5
7.7
2.6
6.9
11.2
8.5
9.2
5.8
4.9
M
7.1
6.2
6.2
M
M
7.2
10.7
M

2.5
5.0
4.0
8.5
7.0
2.0
5.0
2.0
5.0
4.0
5.0
2.0
6.0
9.0
10.0
16.0
14.0
M
c
£
•^
— ^~,
3410
6120
2120
3270
10120
2060
11190
4860
4990
M
5460
1978
1876
M
M
M
7460
M

1500
5750
M
11305
3500
3200
6250
1700
4250
3000
5000
1800
6600
8100
3500
24000
21000
M
Resultant
wind directior
NE
WNW
NNE
S
SSW
WSW
NW
ENE
E
ESE
S
SW
SW
SW
SE
WNW
SSW
W

E
NE
ESE
S
S
WSW
N
NE
E
E
E
SSE
SW
SSW
WSW
WNW
WNW
NNW
<" Q)
<'i
6.9
6.5
5.5
8.8
8.8
15.5
10.9
6.9
7.9
6.3
6.5
8.8
12.5
5.5
10.1
13.5
14.7
12.5

6.8
3.3
4.3
3.7
6.8
4.9
4.3
3.3
9.2
8.1
3.2
1.6
4.5
6.6
15.0
17.3
13.4
5.2
 14
 image: 








   Table 1.  (continued).  METEOROLOGICAL DATA  FOR SELECTED CITIES
            DURING THE  NOVEMBER 1966 AIR POLLUTION EPISODE
Boston, Massachusetts (Logan International Airport)
Date
Nov. 13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
0
m
If
42
39
39
38
54
56
45
34
38
37
40
42
45
51
50
49
50
43
0
o __^
a!
0
5
1
6
9
10
3
0
0
0
2
5
8
10
10
10
8
5
Afternoon
mixing dept
(meters)
1200
1290
900
1100
1610
100
1100
1200
1150
850
500
300
470
250
450
200
750
M
SJ! jj.
11.0
6.0
9.5
6.5
10.5
7.0
15.0
6.0
4.0
7.0
4.0
1.5
2.0
8.0
3.5
5.0
7.0
M
c
.5^
13200
7740
8550
7150
16905
700
16500
7200
4600
5950
2000
450
940
2000
1575
1000
5250
M
•6.1
£t,
NNW
NE
NNW
S
SW
SW
NW
NNW
NNE
NNE
NW
ENE
E
NE
NNE
ENE
S
W
O) w
<'i
16.8
12.9
16.1
10.5
14.7
13.1
19.1
9.2
9.5
8.2
6.2
6.0
8.5
9.5
11.5
12.7
11.4
14.4
Philadelphia,  Pennsylvania (International Airport)
Nov.
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
43
40
41
41
53
54
44
36
38
39
39
50
53
52
46
50
39
36
2
0
3
5
9
10
6
0
0
0
4
7
9
5
8
10
8
6
1300
900
1100
750
500
400
1200
1000
1150
900
600
600
250
900
700
150
2000
M
6.5
5.0
9.0
4.0
4.0
5.0
11.0
5.0
5.0
2.0
3.0
5.0
5.0
8.5
5.5
6.0
9.5
M
8450
4500
10800
3000
2000
2000
13200
5000
5750
1800
1800
3000
1250
7650
3850
900
19000
M
N
N
N
SSW
SW
SW
N
NE
NE
NE
W
W
WSW
N
E
SSE
SSW
W
10.9
7.9
11.2
6.8
8.1
9.5
12.4
9.2
7.9
5.5
4.5
5.0
5.3
7.3
5.9
15.4
11.4
11.9
                                                                     15
 image: 








   Table 1.  (continued).  METEOROLOGICAL DATA FOR SELECTED CITIES
           DURING THE NOVEMBER 1966 AIR POLLUTION EPISODE.


New York, New York (La Guardia Field)
                                          O)
                                          C
Date
Nov.


















13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Washington,


















13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
a>
It
<£
43
41
44
44
55
57
48
36
41
41
46
52
54
52
50
54
44
40
D.C.
45
43
46
45
55
57
50
38
41
41
43
51
58
52
51
49
40
39
o
j|
0
1
3
6
9
10
5
0
0
0
3
5
8
5
7
10
8
5
(National
4
0
3
6
7
8
6
1
5
0
3
7
10
1
6
10
9
7
Afternoon
mixing dept
(meters)
1117
911
1409
1065
577
270
1138
774
1094
682
759
347
469
164
671
650
1437
M
Airport)
1291
957
1047
850
499
533
1199
1138
1181
1261
601
1038
191
1556
M
b
2296
2056
111!
7.6
7.1
7.7
2.8
8.2
5.7
11.0
5.0
4.4
2.7
3.3
4.1
6.2
5.2
2.3
9.8
10.6
M

5.2
2.9
11.3
7.9
2.1
7.2
10.0
4.9
4.1
0.9
2.6
6.5
M
M
M
7.2
6.8
M
c
'S
1
8490
6460
10830
2985
4730
1540
12520
3870
4820
1840
2505
1420
2910
853
1541
6370
15250
M

6720
2775
11840
6710
1048
3835
11990
5580
4850
1137
1560
6750
M
M
M
M
15620
M
"o
.4-
N
N
NNW
SSE
sw
wsw
N
NE
NE
NE
SW
NE
SSE
N
E
SE
SSW
W

N
NW
NNW
S
S
SSW
NNW
NNE
NE
N
S
SSW
S
N
ESE
S
SSW
W
D-D
•n <u
8.8-
h
< *
14.4
9.3
13.7
9.5
10.8
12.2
18.3
10.8
6.6
6.8
5.0
3.9
7.3
8.6
6.0
15.5
13.1
13.2

10.5
6.5
9.5
7.9
7.5
6.9
13.4
7.0
8.5
3.6
4.2
3.7
5.2
5.9
6.0
12.1
11.6
11.5
 Frontal passage  caused mixing depth discontinuity.


  Data missing.
16
 image: 








                                AIR  QUALITY
        Pollutants, after being released into  the atmosphere, are dispersed or
diluted in different ways according to meteorological conditions and the  phys-
ical height at which  they are released.   Because  of this the discussion of air
quality during the episode considers each pollutant or group of pollutants sep-
arately.  It must be recognized that  the  concentration  of the  pollutants  is,  in
part, directly related to  the  site of the  sampler and that the site  is not  uni-
form for all of the cities presented in this report.
GASEOUS POLLUTANTS
Sulfur  Dioxide
        Fossil fuels such as coal and petroleum contain  sulfur,  which,   when
burned,  is  converted  to sulfur dioxide and,  to a  lesser degree, sulfur  trioxide.
Since fossil  fuels are  burned  abundantly  in  the  United  States for heating  and
the generation of electric power,  pollution of the atmosphere  with the oxides
of sulfur is widespread,  especially  in  Eastern and  Mid-Western cities.   Petrol-
eum refineries, smelting plants, coke  processing  plants,  sulfuric acid manufac-
turing  plants,  and smoldering coal  refuse  banks are other major sources of sul-
furous  pollution.
        Considerable evidence points to the fact  that  sulfur oxide  pollution  very
likely  contributes to the  development  of and  aggravates existing respiratory dis-
ease in humans.    In the  documented air pollution disasters,  large  numbers  of
people  became  ill and  many  died.   All  episodes  had common  factors - they
occurred in  heavily industrialized  areas during relatively brief  periods  of anti-
cyclonic weather, with a resulting buildup  of pollutants.
        Mean levels of  sulfur  dioxide  (SO-) are presented graphically for the
period  November 13 through  30,  1966, in Figure  9.   During the week preced-
ing the episode,significant rises were  noted  in mean concentration  levels for
short periods  in most of the cities.  This  is especially evident  for  the  period
November  14 through November 18.   Emission of  sulfur dioxide from  space-
heating sources was  not a significant  factor  in the  increased  sulfur dioxide
levels  because of relatively high  temperatures during  both periods.   In general,
the higher  concentrations of sulfur dioxide  during the  first  period  were due  to
                                       17
 image: 








shallow afternoon mixing depths.   In a few  cases, the sulfur  dioxide  levels
were  apparently  sustained by a change in wind direction  that afforded more
direct transport from  major sources even though surface  wind speeds were  rela-
tively strong.
    0 30

    0 20

    0 10

    0 00



    0 40

    0 30

    0 20

    0 10

    0 00
£


|   0 50

S   0 40

£   0 30

5   0 20

   .0 10

    0 00



    0 30

    0 20

    0 10

    0 00



    0 10

    0 00
           BOSTON, MASSACHUSETTS
            m
         '/AV//W//A
           m
                                          m
           m
               m
           NEKARK,  NEB JERSEY
                                          1
                   m
                       m
m
m
                                              m
                       m
               m
                                   m
           NEW YORK,  NEK YORK
                                                m
                     m
                 I
                                     m
             m
                                                    m
                                                        m
           PHILADELPHIA,  PENNSYLVANIA
                             '/ [77771 V//,
                                                      m
           WASHINGTON,  D  C
           ,mm\
         13  14  15   16   17   18   19  20  21  22  23  24   25   26   11   2B  29  30
         SMTVfTFSSMT»TFSSMT»l
                              DAY OF MONTH (NOVEMBER 1966)

    Figure 9.   Sulfur dioxide, 24-hour mean values, November 13-30,  1966,
                Boston, Mass.; Newark, N. J.; New York City, N.Y.;
                Philadelphia, Pa.; and Washington, D.C.
 18
 image: 








        Sulfur dioxide measurements showed a general upward  trend on  Novem-
ber 21, with  peak concentrations occurring between November 22 and Novem-
ber 24.   The  afternoon  mixing depth and  average  wind speeds both at the
surface and aloft  were low for this f/eriod.   Thus,  the rise  in SOj levels dur-
ing the period was due  to  the  accumulation of sulfurous  pollution from high-
and  low-level  sources.   Improved atmospheric dispersion  on November  25
resulted in the gradual dilution of  the  polluted air.  As the  cold front passed
through on the night of November  25,  the levels fell  off rapidly.
       Mean  concentrations of pollutants give only a  partial  picture of a city's
air quality.   Some knowledge of the variability in concentrations is  equally
important.   The daily pattern,  which is the basic  cycle  of  interest here, is the
result of interactions between source  strength, the dilution capacity  of the at-
mosphere,  and, in some  cases, photochemical reactions.
        Figure  10  presents the diurnal variation of  sulfur  dioxide  levels for se-
lected days during the two periods of poor pollutant dispersion.   The general
pattern of  SO- levels is  evident — a  peak during the morning hours and a
minimum in the afternoon hours,  which, although  lower  than  the  early morning
peaks,  is  still  high when compared to more normal days.
       The high  hourly peak averages,   i.e.,  0.97 ppm  in  New York  City on
November  24,  are well  above  the  level that  the  Public  Health Service has in-
                                                              8            9
dicated to be acceptable for the protection of health and welfare.    Researchers
in New York  City,  assessing consequences of the Thanksgiving episode, found
an increase of approximately 24 deaths per day during the period November 24
through 30.
        Peak  sulfur dioxide concentrations  in  New  York City  during the  Thanks-
giving episode were  not  as high as in previous episodes,  i.e.,  the  November-
December  1962 Air  Pollution Episode.     During the  more recent episode, SO-
levels would have been higher except for the following  reasons:
        1.   The weather  was relatively warm  and thus space  heating
       was at a  minimum.
        2.   Many industrial  plants  and  commercial  establishments  were
        not operating because of the  holiday  weekend.
        3.   Some  process industries voluntarily reduced SO- emissions,
       and power generating units  switched to low-sulfur fuels wherever
        possible.
        Since  Boston  is not far  outside the area defined by the advisory,  its
weather patterns  were very similar  to those of the  cities  included  in the stag-
nation area.

                                                                             19
     318-501  O - 68 - 4
 image: 








   0 70

   0 60

   0 50

   0 40
 E
 S 0 30

 § 0 20

 S 0 10
 z
 £ '0 00

 " 0 30

    0 20

   0 10

    0 00
  PHILADELPHIA, PENNSYLVANIA
                        J L
  WASHINGTON,  D  C
\
         AM    PM   AM   PM
          16 Wed    17 Thurs
                 AM   PM
                  16 Fri
AM  PM
22 TUBS
AM    PM
 23 Wed
AM .  PM
24 Thurs
AM   PM
 25 Fri
AM   PM
 26 Sat
                                  DAY  OF MONTH (NOVEMBER 1966)
        Figure  10A.    Sulfur dioxide  (diurnal  variations)
                       November 16 - 18, and November 22-26, 1966,
                       Philadelphia,  Pa., and Washington, D.C.
   1 00

   0 90

   0 80

 t 0 70

 z 0 60

 | 0 50
 z
 y o 40
 cj
   0 30

   0 20

   6 10

   0 00
  NEW YORK, NEW YORK
                        J
                                    I
                                             I
         AM    PM   AM   PM
          16 Wed    17 Thurs
                 AM   PM     AM   PM    AM   PM   AM   PM
                  IB Fri       22 Tues    23 Wed    24 Thurs
                       DAY OF MONTH (NOVEMBER 1966)
                            AM   PM  AM   PM
                             25 Fri    26 Sat
        Figure  10B.    Sulfur dioxide  (diurnal  variations)
                       November  16 -  18,  and  November 22  - 26,  1966,
                       New York  City,  N.Y.
20
 image: 








Oxides of Nitrogen
        Nitric oxide  (NO) and nitrogen dioxide (NOj)  are  produced by  any
high temperature  combustion process  in which air  is used as an  oxygen source.
Relative levels  of these oxides of nitrogen are also influenced by atmospheric
reactions  that convert  nitric oxide to nitrogen dioxide,  with the rate of con-
version related  to the  intensity of solar radiation,  much as  in  the  production of
photochemical smog.   Nitrogen dioxide, most toxic of  the oxides of nitrogen,
is an important  component in the complex of reactions  producing photochemical
smog.
        Figure 11  presents the mean nitric  oxide  levels  for the 2-week period
encompassing the  episode.    Peak  values  for  nitric  oxide occurred from Novem-
ber 23  to  25, then fell to  normal levels with the  arrival of the cold front.
Mean  nitrogen dioxide  levels (Figure  12),  although lower than  those of  nitric
oxide,  exhibited  the same general pattern.
                NEIARK, NE» JERSEY
         0 50
         0 40
         0 30
         0 20
         0 10
         0 00
                PHILADELPHIA, PENNSYLVANIA
                                            m
                                                      m
                                \U77\W7A\
                WASHINGTON, D  C
             13  14  15   16  17  18  19  20  21  22   23  24  25  26  27  26  29 30
              SHT   »TFSSMT«TFS   SI*T»
                              DAY  OF MONTH  (NOVEMBER 1966)

   Figure 11.   Nitric oxide  (NO) 24-hour mean values
                November 13 -  30, 1966, Newark, N.J.; Philadelphia,  Pa.;
                and Washington,  D.C.
                                                                              21
 image: 








    0.20
    0.10
    0 00


    0 10
    0 00


    0 10
    0.00
            NEWARK,  NEK JERSEY
PHILADELPHIA,  PENNSYLVANIA
WASHINGTON, D. C
 P7771 V7771 UTT\ V77A fTTT) trm, rrm 17/71
         13  14  15   16  17  18   19  20  21   22   23  24   25  26  27   28  29   30
          SMTHTFSSMTKTFSSMTK
                              DAY  OF  MONTH  (NOVEMBER  1966)
   Figure 12.  Nitrogen dioxide (NC>2) 24-hour mean  values
                November  13  -  30, 1966,  Newark,  N.J.;  Philadelphia, Pa.;
               and Washington, D. C.
        Nitric oxide  concentrations exhibited a pronounced diurnal variability
(Figure 13),  reflecting three cyclic factors:  (1)  the dilution capacity  of the
atmosphere,  (2) the rate of photochemical  conversion  to  nitrogen  dioxide,  and
(3) the strength of combustion sources.   These  factors combined to produce three
features  in the nitric  oxide diurnal  pattern:
        1.   The minima during  the afternoon are  attributed to maximum
       conversion of  the nitric  oxide  to nitrogen  dioxide,  enhanced
        atmospheric dilution, and  decreased emissions,  i.e.,  less auto-
        mobile traffic.  These minima  existed in  the afternoon  hours
        during the advisory  period even though atmospheric dilution was
       extremely limited.
        2.   The high  overnight  concentrations of nitric oxide are  due to
        a reversal of the influences  from source strength, dilution  capac-
        ity, and  conversion rate.   During late  fall and winter,  levels
        begin to  increase in  late afternoon and peak in the mid-   to
        late-evening  hours.   On Thanksgiving Day,  November  24, Phila-
        delphia's peak hourly nitric  oxide level of 1.83  ppm occurred
        between 11 p.m. and midnight.
22
 image: 








       3.   The characteristic morning peak was a result of the increased
       emissions associated with the beginning  of the day's activities.
       The low inversion that  frequently forms  overnight confines increased
       morning emissions and further  accentuates  morning concentrations.
       With the breakup of  the  inversion, the  mixing volume  increases
       and the ambient  concentration begins  to decline  even though  emis-
       sions may  continue at relatively high  rates.
       Levels  of  nitric  oxide at Philadelphia  and Washington, D.C.,  during the
November  16 through 18 period  were much lower than during  the episode.   Al-
though conditions for conversion of nitric oxide to nitrogen dioxide by photo-
chemical reactions were similar and  mixing depths were  extremely shallow during
the two periods,  higher  surface wind speeds account for  the lower nitric  oxide
concentrations  in  the first period.
          A«   PM   AM   PI
           16 »ed    17 Thurs
AM   PM     IM   PM   AM   PM   AM   PM    AM   PM
IB  Fri      22 Tues    23 »ed    24 Thurs    25 Fn
      DAY OF MONTH (NOVEMBER 1966)
IM    PM
 26 Sat
      Figure 13A.   Nitric oxide (diurnal  variations),  November 16 - 18,
                    and  November  22 - 26,  1966, Philadelphia, Pa.
                                                                              23
 image: 








            WASHINGTON,  D  C
         AM    PM   AM   PM   AM   PM    IN   PM   AM   PM   AM  PM   III   PM   III   Pll
          16 Hffd    17 Thurs    18 Fri-    22 Tues    23 Hed   24 Thurs    25 Fn     26 Sat
                                 DAY OF MONTH (NOVEMBER 1966)

       Figure  13B.   Nitric oxide (diurnal variations),  November 16 -  ?8,
                     and  November 22 - 26,  1966,  Washington, D.C.,
                     and Philadelphia,  Pa.
        The features in the diurnal pattern of variation for nitrogen dioxide levels
(Figure 14) are  not as pronounced as the nitric  oxide pattern because  of the
smoothing effect of the photochemical conversion of  nitric oxide to nitrogen di-
oxide.   However,  the conversion process contributes  to the afternoon  concentra-
tion and  sustains the  nitrogen dioxide level  when  the dilution  conditions are
usually best.
    0 10
     00
    0 20
    0 10
    0 00
           WASHINGTON, D  C
           PHILADELPHIA, PENNSYLVANIA
         AM   PM   AM   PM
          16 »ed    17 Thurs
AM   PM     AM   PM    AM   PM   AM   PM   AM  PM   AM    PM
 18 Fn      22 Tues     23 Wed    24 Thurs    25 Fri     26 Sat
       DAY OF MONTH (NOVEMBER 1966)
        Figure 14.     Nitrogen dioxide  (NC^) (diurnal  variations)
                       On November  16 - 18,  and November 22 -  26,  1966,
                       Washington,  D.C.  and Philadelphia,  Pa.
 24
 image: 








Total Hydrocarbon
       Gaseous hydrocarbon  compounds  in  the  atmosphere consist of stable hydro-
carbons such as methane, which  do not participate in atmospheric photochemical
reactions,  and reactive hydrocarbons such as olefins and aldehydes, which are,
in effect,  raw materials  for the  reactions that  produce the constituents of
photochemical  smog.   The stable  portion consists of a constant geophysical
level of methane  from natural  decay processes,  and variable  contributions of
methane  and other stable hydrocarbons from gas main  leaks, sewage treatment,
motor vehicle exhaust, and similar sources.   The reactive hydrocarbons in the
atmosphere result  essentially  from incomplete combustion and  evaporation  of
organic compounds, of which  the prime contributor is  gasoline.
       Most  hydrocarbon substances are normally toxic only at concentrations
of several  hundred parts  per  million.  However,  a  number of  hydrocarbons can
react photochemically  at very  low concentrations to produce   irritating and
toxic substances.   There  is no doubt that the atmosphere of many polluted
areas contains  hydrocarbons that  are  capable of producing, experimentally,
cancer in animals.
       Figure 15  presents the daily variation of total  hydrocarbon levels  for
Newark, Washington,  D.C.,  and Philadelphia.   Methane concentrations  are
plotted  for Philadelphia, the only  city for which such data were available.
            NEWARK, NEK JERSEY
                                                        >, vrm
            PHILADELPHIA,  PENNSYLVANIA
                    METHANE FRACTION
            WASHINGTON, D  C
                                                                 \VTTAW7\\
        13  14   15   16   17  18   19   20  21  22  23  24  25   26   27   28  29  30
         SMTNTFSSMTWTFSSMTN
                              DAY OF MONTH (NOVEMBER 1966)

    Figure  15.   Hydrocarbons  24-hour mean values
                November  13 - 30,  1966, Newark,  N.J.;  Philadelphia,  Pa.
                and Washington, D.C.
                                                                             25
 image: 








One theory suggests that the methane concentration may be interpreted  as an
indicator of  natural  vertical ventilation.   The methane  concentrations, which
are relatively  constant  from day to day,  did rise on  the days of restricted nat-
ural ventilation,  i.e.,  on  November 23 through 25.   With  improved ventilation
conditions after the  25th,  the levels  of methane and total  hydrocarbon returned
to normal  in all cities.
        The pattern of diurnal  variation (Figure 16) of total  hydrocarbon shows
a fairly consistent morning  rise, which is  coincident  with the morning traffic
surge,  after  which the  level declines as a result  of both reduced emissions and
improved ventilation  later in the  morning.   Since  the concentration of the
methane portion  of the  total  hydrocarbons  responds  primarily to variations  in  the
ventilation,  the  remainder, or non-methane,  is responsible for the  principal
features in the diurnal  patterns that correspond closely with patterns of  traffic
flow.
   10
                      „   A TOTAL  HYDROCARBONS
    0|     .    l     .    I   "ETHANE |
          PHILADELPHIA, PENNSYLVANIA
          WASHINGTON,  D  C
   15
   10
    5
       AM    PM   AM   PM   All  PM '    AM   PM   AM    PM   AM  PM   AM   P«   AM   PM
        16 Hed   17  Thurs    IB Fri      22 Tues    23 »ed   24 Thurs    25 Fri    26 Sat
                                DAY OF MONTH (NOVEMBER 1966)

         Figure 16.   Hydrocarbons  (diurnal variations)
                      November  16  - 18,  and November 22 - 26,  1966
                      Philadelphia,  Pa.,  and Washington,  D.C.
 Carbon Monoxide
        Carbon monoxide (CO) is produced by  the  incomplete combustion  of any
 organic  fuel.   Relatively complete combustion  takes  place in steam boilers  and
 other  fueled  equipment  that operates with an excess  supply of air;  however,
 the  outstanding  exception, the gasoline-powered internal-combustion engine,
 delivers the performance expected  of  it only when operated  with slightly less
 26
 image: 








air than is needed to completely burn all hydrocarbons to carbon dioxide.  Hie
ubiquitous automobile is,  therefore, the principal source  of carbon  monoxide.
        Carbon monoxide is a  toxic gas having  the  ability to  replace oxygen
that is  in combination  with  hemoglobin in circulating  blood.   This  character-
istic may make  it a  health hazard  to sensitive  individuals even at  levels found
in the ambient atmosphere of  most  urban  areas.   In the  passenger  compartment
of motor vehicles in  traffic,  carbon monoxide may  reach  levels sufficiently
high to interfere with man's driving ability and thus pose  a safety  hazard in
virtually any  community.
        The daily variation of mean levels of carbon monoxide is  plotted  in
Figure 17.  The  same general pattern  is  evident here  - a rise  in the concen-
trations as the stable air  mass settles over a  metropolitan  area, and a steadily
downward trend as the clean air mass  moves  into the area.
           13  14  15  IB   17  18   19  20  21  22  23  24  25  26   27  28  29  30
            SMTKTFSSMTWTFSSMTW
                                DAY OF MONTH (NOVEMBER 1966)

   Figure  17.  Carbon monoxide  (CO) 24-hour mean  values
               November  13 - 30,  Newark,  N.J.; New York City,  N.Y.;
               Philadelphia, Pa.; and Washington,  D.C.
                                                                             27
 image: 








        Figure  18,  the diurnal  variation of carbon monoxide,  is similar to the
nitric oxide  pattern (Figure 13).  The  carbon monoxide levels  follow the traffic
pattern  with  peaks in the morning and evening.   Improved ventilation during
the afternoon decreases the concentration  at that  time  making the morning and
evening peaks more prominent.   Concentrations of this pollutant  were much
higher during the episode than during more  normal periods.   New York's peak
value on November 24,  for example, was 35 ppm,  but on November  22 it was
8 ppm.
         NE« YORK, NEK YORK
         PHILADELPHIA, PENNSYLVANIA
                               J L
         WASHINGTON,  D  C
      AM   PH  AM   PM
       16 Ned   17 Thurs
AM   PM    AM   PM    AM   PM    All   PM
18 Fri      22 TUBS    23 Wed    24 Thurs
      DAY OF  MONTH (NOVEMBER  1966)
AM  PM   AM   PM
 25 Fri    26 Sat
  Figure 18.   Carbon monoxide (diurnal  variations)
               November  16 - 18, and November  22  -  26, 1966,  New York
               City, N.Y.;  Philadelphia,  Pa.; and Washington,  D. C.
 28
 image: 








PARTICUIATE POLLUTANTS
        Porticulates of solids, and occasionally liquids, constitute  a relatively
small (by weight)  but  important  portion of polluted air in most cities and towns
in the United  States.   These particulates may be either so large  that  they rapid-
ly settle to the  ground, or so small that  they remain suspended in the  air  until
they are removed  by such a natural cleansing phenomenon as  rain.  Particulates
may be quite complex  in chemical composition.  The  organic  materials found in
airborne particles  may  contain aliphatic and aromatic  hydrocarbons, acids, bases,
phenols, and  other compounds.   Airborne particulates  may also contain any of a
side range of inorganic and metallic  particles such as silica,  lead sulfate,
ammonium  sulfate, aluminum,  iron,  lead,  and  copper.   Sources of particulates
include fuel combustion,  including that of gasoline; various  manufacturing and
processing  operations,   including production of  steel,  cement,  and petroleum
products; and open burning and  incineration  of refuse.
        Particulate air pollution  is widely regarded  as  objectionable because it
interferes with visibility, and  is associated with soiling and corrosion  of  metals,
fabrics, and other materials.  Adverse effects  on   health from  particulate  air
pollution are  far more  subtle,  but are none the less significant.   In general,
concern about the health effects of particulates is  related to (l)the ability of
the human respiratory  system to  remove such particulate air  pollution  from in-
haled air and  retain  it in the  lung, (2) the presence  in particles  of  mineral
substances  having  toxic or other physiologic  effects, (3) the presence of poly-
cyclic hydrocarbons  having demonstrated carcinogenic  (cancer-producing)  prop-
erties,  (4) the  demonstrated ability of  some fine particles to enhance the  harm-
ful  physiologic activity of irritant gases when  both are simultaneously   present
in inhaled air,  and  (5) the ability of  some mineral particles  to   increase  the
rate at  which sulfur  dioxide in the atmosphere  is converted by  oxidation  to  the
far  more physiologically active sulfur  trioxide.
        Figure  19 presents  the daily variation  of total  suspended-particulate
levels and  the autumn mean levels for  the cities studied.  Concentrations rose
in all of the  cities during the stagnation;  however,  only Philadelphia and
Baltimore  were in  the  advisory area.   Concentrations definitely rose in Phila-
delphia  during the preceding week, while levels in the  other  cities showed only
a slight increase.
        Levels recorded in Philadelphia, Worcester, and  Boston  represent multiple
station averages.   The  maximum  city-wide average  concentrations  in Philadelphia
(390 Hg/m3),  Worcester  (198  Mg/m3), and Boston (238 Mg/m3) exceed maximum con-
centrations recorded  for an autumn period since 1961 at the  single-site  National
                                                                              29
 image: 








    200
    100
    300
    20°
    too
            KORCESTER, MASSACHUSETTS
                     i
                         i
        i
AUTUMN
(1961-1965)
                                                MEAN
            BOSTON, MASSACHUSETTS
                     BENZENE SOLUBLE
                     ORGANIC FRACTION
                   AUTUMN (1961-1964) MEAN
                         1

                                      1
    400
    300
    200
    100
      o

    300
    200
    100
            PHILADELPHIA, PENNSYLVANIA
             m
    m
                         m
            m
m
                                                  m
                                 m
                         m
                                           m
                                      m
                                                               AUTUMN  (1961-1965) MEAN
                 m
            BALTIMORE, MARYLAND
                                  1
                       AUTUMN (1961-1965) MEAN
                         m
                         1
1
                                               m
                                                                   m
       m
         13   14   15  16   17   18   19  20   21   22   23  24   25  26  27   28   29  30
         SMT*TFSSMT»ITFSSMT«
                                 DAY OF  MONTH (NOVEMBER 1966)
* 48-hour  total was averaged over the two days  involved.
Figure  19.      Suspended particulates (24-hour accumulation),  Worcester, Mass.;
                Boston, Mass.; Philadelphia, Pa.;  and  Baltimore, Md.
 30
 image: 








Air Surveillance Network stations.   These  single-site  maxima  are  322 u.g/m3 For
Philadelphia, 196  Hg/m3  For Worcester, and 209 HgA3 for  Boston.
        Measurements  taken  with AISI tape samplers represent a  major source  oF
inFormation about air quality  during  the episode.   These AISI  samplers  collect
Fine suspended particulates on a filter tape for consecutive 2-hour periods.  The
soiling  capacity  of the air drawn through  the filter tape  is  determined   by
comparing the  transmission of  light through the sample  and through  the  clean
tape.    The soiling  index is reported in Coh  units, the  "coefficient  of haze"
per 1000  linear feet.
        The daily variation in soiling  index levels  is  presented   in   Figure   20.
These patterns  are  more distinctive than the  ones  for the  gaseous pollutants.
Although  Allegheny  County,  Wellsburg, Vienna,  and  Huntington were not  in-
cluded  in  the advisory, daily variations were very similar to those  in the  cities
that were  included.   Peaks  in the graph during the week  preceding  the episode
show a  similarity in  the  time  of occurrence to the peaks for  the gaseous pollu-
tants.
        Saturday-Sunday levels are usually  lower than  weekday levels  for most
pollutants;  however in some  cases (i.e.,  on  November 26 and  November  27)
most pollutants appeared  to  be above average.  This might have been caused by
increased  traffic  as people returned home  after the holiday.
                                                                             31
 image: 








          BALTIMORE,  MARYLAND
                               mW/,
                                                         \vmvmvm
    2


    1


    0

I—
LLJ
LLJ


S  6
LU  u
Z

^  5
t=t

°  4


°  3
Z
CD
"  2

LLJ

    '
          FAIRFIELD, CONNECTICUT
         77771
,V777\777A\
                                         m
NEW YORK,  NEW YORK
                   1
                                    1
          CHATTANOOGA TENNESSEE
                                      1
                                                   m
                                                         LL
       13  14  15   16   17  IB   19   20  21   22  23  24  25  26   27   28  29  30
        SMT    HTFSSMTHTFSSMTW
                              DAY OF MONTH (NOVEMBER, 1966)

  Figure 20A.   Soiling index ("coefficient of haze"  per  1000 linear feet),
                24-hour mean  values, November  13 - 30,  1966,
                Baltimore, Md.; Fairfield,  Conn.;  New York  City, N.Y.;
                and Chattanooga,  Tenn.
 32
 image: 








     4|-   PHILADELPHIA, PENNSYLVANIA
 £   5
 <=>
 O

 «   4

 -   3
 C3
 z
 3   2




          NEWARK,  NEW JERSEY






           BIRMINGHAM. ALABAMA


           KELLSBURG, «EST VIRGINIA












          VIENNA, VEST VIRGINIA

             1 VTTTl F7771 V//A

       13   14  15  16  17   18  19  20   21  22   23  24   25  26  27   28  29  30
        SMT»TFSSMT»TFSSMTK
                            DAY OF MONTH (NOVEMBER 1966)

Figure 20B.   Soiling index ("coefficient  of haze"  per  1000  linear feet),
              24-hour mean values,  November  13 - 30,  1966,
              Philadelphia,  Pa.;  Newark,  N.J.;  Birmingham, Ala.;
              Wellsburg,  W.Va.; Vienna, W.Va.; Huntington, W.Va.;
              and Allegheny County, Pa.
                                                                             33
 image: 








 image: 








                  SUMMARY  AND  CONCLUSIONS
        This report  has  documented  the  Thanksgiving 1966 Air Pollution Episode
in the Eastern  United States  in  terms of the daily meteorology and ambient air
quality.   Analysis  of the  available air quality data indicates that the Air Pol-
lution Potential Forecast Program (APPF) of  the  Public  Health  Service and the
Weather Bureau did effectively  forecast the  stagnation.   The increase in levels
of the pollutants during the same period is  indicative  of  stagnation regardless of
the city considered.   Advance warning  is  a necessary step  to effective control.
To effectively  use  APPF,  municipalities must reduce emissions of  air  pollutants
until  meteorological  conditions change  to  provide  better ventilation for the  af-
fected areas.   Monitoring and forecasting  at local levels to augment  the APPF
is also  needed.
       A period of restricted  natural ventilation on November 17 covered  a
small  area and was short  in duration,  precluding it from  generating an air pol-
lution potential advisory.   However, air quality did deteriorate  significantly dur-
ing this  period;  pollutant levels recorded in some cities  approximated peak con-
centrations during  the subsequent episode.
        In general,  public concern  about air pollution (as judged by  publicity)
is minimal except  during  those periods  when the conditions of restricted natural
ventilation are  sufficiently extensive to warrant issuing an  air pollution  potential
forecast.   Public attention must be focused  on the fact that there are additional
periods when  local  conditions can effect a  comparable deterioration of communi-
ty air quality.
       As in  other  documented  air pollution episodes,  the  high  levels of air pol-
lution in the eastern United  States during  the period from  November  24 through
30,  1966, created adverse health effects.    Researchers in  New York  City found
an increase in death rate of approximately  24  deaths  per day during  the  period.
Recently published information indicates that periods of high air pollution   not
                                                                      12
considered "episodes" may also  be  associated with increased mortality.
                                      35
 image: 








 image: 








         APPENDIX:   METEOROLOGY  AND  DISPERSION
                        OF  AIR CONTAMINANTS
       Many of man's activities result in  the  introduction  into the air of  sub-
stances,  which are detrimental to his  own health and well-being.  Until fairly
recently  the ocean of "clean" air has been  proportionately large enough  that,
except for some small local  areas, pollutants were quickly diluted  to  insignifi-
cant levels.  A constantly  increasing  population, which adds pollutants both
directly and indirectly,  has  resulted  in  the frequent  incapability  of atmospheric
dispersion to maintain acceptable air  quality.   In a large  sense  the  dispersion
of pollution in the atmosphere is only a temporary measure,  because  pollutants
must eventually either be removed from  the  air  by various natural  processes or
accumulate  indefinitely on a world-wide basis.   Although  removal mechanisms
have been studied, they are  poorly  understood  at present.   For example,  no
mechanisms  for the destruction or removal of carbon monoxide  in the  atmosphere
have been found.
DILUTION  AND DISPERSION
       A situation involving  the  constant  rate of emission  of smoke from a stack
illustrates the  effect  of horizontal dilution.  For example, a doubling of wind
speed from  one period to another doubles  the  volume of air into  which the smoke
is  emitted,  and the concentration of smoke  is reduced by a  factor  of  2 (Figure
21 A).   In general, a stronger wind disperses pollutants  more widely.    However,
high winds blowing over tall stacks and tall buildings can produce eddies  on the
lee sides  that  will bring the stack emissions to  the surface  with  almost  no dilu-
tion.   On the  other  hand,  emissions from tall stacks  can be dispersed widely by
light winds, which provide  ample dilution, before reaching surface levels  (see
Figure  21B).
       Vertical dispersion depends on the degree of stability of the atmosphere.
An understanding of the  physical reasons for atmospheric behavior requires some
familiarity with the gas  laws of  Boyle and Charles.   Essentially, these laws state
that when the  pressure on a  parcel of gas changes there will also  be  a  change
in the  volume  and temperature.   Atmospheric  pressure changes  with elevation.
At  sea level the pressure averages 14.7 pounds  per square inch,  but  at about
18,000 feet above  sea level  the pressure  is  reduced  by a factor  of 2.  Accord-
ing to  the  gas  laws,  this reduction of pressure with  increasing  elevation is suf-
                                      37
 image: 








ficient  to  lower the temperature 5.4  F for  each  1000-foot increase in eleva-
tion, which defines the specific temperature  gradient  known as the dry adia-
batic lapse rate.   When the vertical  change  in temperature  of the atmosphere
matches the dry adiabatfc  lapse  rate,  then  it is said to be  in the neutral con-
dition with respect to stability.   The  temperature of any  parcel  of air  that  is
moved  vertically will  also change at  that rate  and, as  a  result,  will be  indis-
tinguishable from the air that surrounds it.
        Different degrees of stability result  from the departure  from the  neutral
or dry  adiabatic  lapse  rate.   The  isothermal  condition,  in which the tempera-
ture does not  change with elevation,   is a stable condition.   Even more stable
is  the situation wherein the temperature rises with  an  increase in elevation. This
is  the  "inversion" condition, so  named because  it  is the  inverse of the general
change in temperature  that is found in the  atmosphere.
        Under  stable conditions  the  winds at upper  levels  have little  interaction
(no vertical interchange) with  those at lower levels.  Winds  near the surface  are
usually weaker than winds at upper levels because of friction  with the  earth's
                WIND SPEED, 5 mph
            WHO SPEED, LIGHT
             -»IHND SPEED, 10 mph|
                                                   ->  WIND SPEED, STRONG
    Same amount of smoke is spread over a
    different distance according to
    wind speed
                (A)
Plume may be brought to surface »ith little
dilution by eddies during strong winds.
               (B)
          Figure  21.     Effect  of  wind speed on emissions from  stacks.
 38
 image: 








 surface.   Less lateral  movement reduces the horizontal  dispersion of pollutants so
 that,  under stable conditions, concentrations of pollutants usually build  up rapid-
 ly.   Vertical  mixing is  also  restricted during stable  conditions.
        The  neutral condition is  unusual.   The  lapse rate  of the  atmosphere ordi-
 narily is less than 5.4°F temperature change per 1000-foot elevation change.  In
 such a case, a parcel of air that is lifted  will be  cooler  at  the  new level than
 the  air surrounding it.   Because  it is cooler,  it will be more dense and will tend
 ro return to its original  position.   If it  returns to its original position,   it  will re-
 gain its previous  temperature (and density)  and be in equilibrium.  Air moved to
 a lower level  would become  warmer than the air surrounding it.   With a rela-
 tively warmer  temperature, it would be  less dense and  would tend  to rise  to  its
 former level.   This tendency of a parcel of air to  return to  its original  level
 exemplifies  a  stable condition.
        An  unstable condition occurs when the temperature decrease with height
 is greater than the dry adiabatic lapse  rate.   In this case  a parcel of air that  is
 lifted will  be  warmer  than the temperature  of the surrounding air at the new
 level.   A  parcel  of air that is  displaced downward  will become  cooler than
 the  air  around it.   The accompanying change in density  in  both  cases   then
 causes the  parcel  of air to move even  farther away from  its  original  position.
 Unstable layers are not  unlimited.   They are always bounded by  either  the
 earth  or stable layers  of air,  and the  accelerating  force  eventually meets  re-
 sistance and vertical  motion  stops.   During  unstable periods vertical movements
 are  accelerated,  and pollutants  are  well mixed throughout the unstable  layer.
 Horizontal  mixing is usually  improved  because wind  speeds near  the surface are
 likely to be greater.   In general, wind speeds aloft are  greater  than those near
 the  surface, but under unstable  conditions the surface winds will  be nearly  as
 strong as those aloft.
 DIURNAL PATTERN  OF DISPERSION CAPACITY
       Changes in stability usually  occur as the result of local heating or  cool-
ing of the  lower levels of the atmosphere.   Although temperatures of the upper
levels  do change,  larger changes are on a  seasonal  basis  with smaller day-to-
day  changes, and  relatively small hour-to-hour changes.   The hour-to-hour
temperature  change at  the  surface,  however,  is much larger.   On clear  days,
incoming  solar radiation  warms the earth's surface rapidly, and on clear  nights
outgoing radiation  cools  the  surface.   The surface  layer of air is  warmed or
cooled by contact  with the earth's surface.   Enough air movement to circulate
this  air vertically  to some  extent is  always  present.   A cooled layer may be
only a few  feet deep on a  quiet night,  and sometimes is  evident  visually in the
                                                                              39
 image: 








form of a ground-hugging fog  layer.  At other times  the  comparatively  cool
layer may  be several hundred  feet thick.  This situation,  labeled "inversion,"
occurs when the air aloft is warmer  than the air  below.   It  does not matter
whether the  air aloft becomes  warmer or the surface air becomes cooler,  the end
result of relatively warm air above cooler air is the determining factor,  indi-
cating stable conditions.   Pollution emitted  into the stable layer will  remain
within the layer, which is  frequently the case  in the early morning.  After sun-
rise,  as the  ground  is heated, the air in contact with the ground  is  warmed,
becomes  less dense, and rises, somewhat as  a bubble  rises in a  liquid, to the
elevation where  its density  is  equal  to  that  of  the air around  it.  These  rising
currents carry  heat from the surface  that eventually raises the  temperature of a
thicker and thicker  layer of air.   This  circulation of air  also  carries  the pollu-
tion, which  has  been released into it at lower levels,  to greater and greater
heights.   The  level  to  which these currents  penetrate is called the "mixing
depth."   The distribution of pollution to higher levels has the added advantage
of better  horizontal  dilution, in  addition to  vertical dispersion,  because  wind
speeds at the upper levels are likely to be greater.
        The diurnal change  in surface temperature with  lower temperatures  at
night and  higher temperatures during the day produces  changing lapse rates,
which affect the stability of the  air.   Ordinarily,  during each day the  noc-
turnal stability is  replaced  by daytime  instability.  Although pollution concen-
trations may become high during  the overnight stable period,  pollution will
usually be widely dispersed during the  unstable period  associated with the day-
light hours.   The  daytime dispersion usually results in little  carry-over of pol-
lution from one  day to the next.

STAGNATIONS
       Under certain situations carry-over of pollution  may occur  from one day
to the next.   In the area covered by an anticyclone only the  very lowest
levels may warm enough during the  daytime hours to  reach the unstable  condi-
tion that helps in  the dispersion of pollution.   In this  restricted depth (often
1000 feet  or less), the concentration of pollutants will  remain  high.   An  anti-
cyclone,  or "high-pressure  system,"  is  so  named  because  a greater mass  of air
over  an  area will  cause a  barometer, which  measures the weight of  the   air
above it,  to rise to a  "higher" reading.  The  air should  not be thought of as
being piled  higher over that  spot, but  as  being cooler  and denser and having
a  greater mass.   Because the  pressure  is higher in the area of the high,  air
flows out from  it at the surface  toward  places  of lower pressure, and  air from
above settles to replace it.  This deep  layer of settling air  warms throughout
 40
 image: 








at 5.4°F per 1000 feet of settling to create relatively warm air aloft over a
wide  area.   Warm air aloft  indicates stability; and in the case of a high, not
only  the  surface level, but also a layer many thousands of feet deep may become
stabilized.
       When a high covers an area, a  double threat  of increase  in pollution
concentration exists.   The usually  clear skies and  light winds that accompany
a high are  conducive to surface-based nighttime  radiation  inversions  thaf are
overlaid  by other stable  layers due to the  subsiding air of the  high.   Even  if
the nighttime  surface inversion is destroyed during the day by  surface  heating,
there  is  still no break-through from  the surface into a vigorous  cleansing  air
stream.   The stable  air aloft in  a subsiding  high  generally is sluggish  in  its
horizontal movement  and continues to resist  vertical movement  from below.
Because  the pollution is  not completely carried away, a  portion of one day's
pollution is added to the next,  and  concentrations of  pollution increase to ob-
noxious  and dangerous levels.
FORECASTING  STAGNATIONS
        When an attempt  is made to  forecast a potential for high air pollution
because  of weather  conditions in a  given  area,  several objective parameters
are checked  by the  air pollution potential forecasters.   The height to  which
mixing will  occur (mixing depth) and the average  speed of winds through  this
mixing depth are calculated by  electronic computers,  using data  obtained  from
all the upper air (radiosonde)  observation stations  in the  United States.  Data
on  current  morning conditions  collected at T200  Greenwich time  (0700 EST) are
used  in these  calculations.   Forecasts are  then made  of  mixing depth and aver-
age wind speed for the current afternoon  and the  afternoon of the following
day.   The  product of the mixing depth  and  the average wind speed  through the
mixing depth is called the "ventilation."
       Observations indicate  that  no stagnation of consequence will occur if  the
"ventilation" during  the afternoon  hours exceeds  6000  cubic meters per second or
if the average  wind speed is  greater than  4  meters per second (about 9 miles
per hour).   Once  these criteria  for minimum  ventilation and wind speed  are met,
forecasters must then consider  other parameters.*   If the appropriate conditions
are found over an area of at least 75,000 square  miles (roughly the size of
Oklahoma), and appear  likely to persist for  at least 36  hours,  a potential  for air
pollution is  considered to exist and a forecast message delineating the area is
prepared  for use by  air pollution and public health agencies.
 *The presence of precipitation or the imminent approach of a  frontal  system
  automatically excludes an area from the high  pollution potential  forecast.
                                                                             41
 image: 








 image: 








                             REFERENCES
 1.   Firket, J. (Secretary):  Sor les causes des accidents survenus dans la
      vallee de  la Meuse, los des  brouillards de December 1930.   Bull. Acad.
      Roy.  Med.  Belg.  11:683-741, 1931.
 2.   Schrenk,  H. H. ,  et al.   Air Pollution in Donora, Pa.  Epidemiology, of
      the Unusual  Smog Episode of October  1948.   Public Health  Bulletin
      No.  306, Federal  Security Agency, Washington,  D.  C.,  1949.
 3.   Ministry of Health:   Mortality and  Morbidity  During the London  Fog of
      December 1952.   Report by a Committee  of Department Officers and
      Expert Advisers appointed by the  Minister of Health.    Reports on Public
      Health and Medical  Subjects, No.  95, H. M.  Stationery  Office, 1954.
 4.   Fog and Frost.  British Med. J.  2:1626 (Dec.  15) 1962.
 5.   Greenburg, L., et al.   Report of an Air  Pollution Incident  in New York
      City,  Nov.  1953.   Public Health Report  77:7-16  (Jan.) 1962.
 6.   Scott, J. A.   The  London Fog of December  1962.  Med.  Officer 109:250,
      1963.
 7.   Greenburg, L.  Air  Pollution Episode  in  New  York City  in  1963, read
      before the 58th Annual  Meeting of the Air Pollution  Control Association,
      Toronto,  Canada, June  20-24, 1965.
 8.   Air Quality Criteria for  Sulfur  Dioxides.   DHEW,  PHS.  March  1967.
 9.   Hearings before the Committee on Interstate and Foreign Commerce,
      House of  Representatives.   U.S.  Government  Printing Office,  1967.
10.   Lynn,  D. A.,  Steigerwald,  B.  J., and Ludwig, J. H.  The November-
      December  1962 Air  Pollution Episode  in the Eastern United States.  PHS
      Publ.  No. 999-AP-7.   1964.
11.   Air Pollution - 1966, Hearings before  a Subcommittee on Air and  Water
      Pollution  of the Committee on Public Works,  United States Senate.  U.S.
      Government Printing Office,  1966.
12.   Greenburg, L., et al.   "Report of an Air Pollution Incident in  New
      York  City,  November 1963."  Public  Health  Reports  78:1061-64.
                                     43
 image: 








 image: 








                     SELECTED  BIBLIOGRAPHY
Miller,  M.  E.  and Niemeyer, L. E.   "Air Pollution  Potential  Forecasts — A
Year's Experience."  Journal  of  the Air Pollution Control Association
13:205-210  (1963).
Meetham, A.  R.  Atmospheric Pollution.  Pergamon Press,  pp. 266-272.  1956.
Simpson, C. L.  Some  Measurements of the  Deposition of Matter and  Its
Relation to  Diffusion  from a  Continuous  Point Source  in a Stable Atmosphere.
HW-69292  Rev.  Richland,  Washington.  1961,  22  pp.
Niemeyer,   L.  E.   "Forecasting Air  Pollution  Potential."  Monthly  Weather
Review  88:88-96 (March 1960).
Boettger, C. M.   "Air Pollution Potential East of the Rocky Mountains:
Fall  1959."  Bull.  Amer. Society 42:9 (September 1961), pp. 615-620.
Korshover,   J.   "Synoptic Climatology of Stagnating Anticyclones."  SEC Tech-
nical Report A60-7,  Robert A.  Taft Sanitary  Engineering Center (Cincinnati:
1960).
Holzworth,  G.  C.   "Estimates of Mean Maximum Mixing Depths in the Contin-
uous United States."  Monthly Weather  Review 92:5 (May  1964) pp. 235-242.
Hosier,  C.   R.  "Climatological Estimates of Diffusion  Conditions  in  the  United
States." Nuclear Safety 5:2  (Winter  1963-64).
Miller,  M.  E.   "Forecasting Afternoon Mixing  Depths and Transport Wind
Speeds."  Monthly Weather Review  95:1 (January 1967) pp.  35-44.
Davis,  Francis  K. and  Newstein, Herman.   "Meteorological  Analysis of Novem-
ber  1966 and  January 1967 Air Pollution Episodes in  Philadelphia," read before
the 60th Annual  Meeting of  the  Air Pollution Control Association,  Cleveland,
Ohio, June 1967.
                                      45
                                  U. S. GOVERNMENT PRINTING OFFICE • 1968 O - 318-501
 image: 








 image: 







Next Page or group of Pages Next Occurence of Search Term