INTERSTATE AIR POLLUTION
STUDY
B!-STATE Dl VEOf'MINT
AGENCY
ST. LOUIS DF I'AITM-ItlT OF
HEALTH AND HOSP IMS
ST. LOUIS - I) I* ISI'IN OF
AIR POLLUT ON :(HfROL
PHASE n PROJECT REPORT
EAST SI. IOUI! "AIR
POLLUTION CCH1R5L
COMMISSION
ST. LOUIS COLIN Y
HEALTH Di:PARrHEf.hNl
OF PUBLT, H-/_"H
CHAMBER OF COMMEK'l E OF
METROPOLITAN S' iOUIS
MFTFOROIOGY AND TOPOGRAPHY
ILLINOIS Alk PiiLi.l TION
CONTROL BO^Ri)
DHI W
PUBLIC HEM.Th SCI VICE
-------
-------
INTERSTATE AIR POLLUTION STUDY
PHASE II PROJECT REPORT
V. METEOROLOGY AND TOPOGRAPHY
prepared by
D. O. Martin
P. A. Humphrey
J. L. Dicke
U.S. Environmental Protection Agency
Region 5, Library (5PL-16)
230 S. Dearborn St-eet, Room 1670
Chicago, IL 60604
U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
Bureau of Disease Prevention and Environmental Control
National Center for Air Pollution Control
Cincinnati, Ohio
April 1967
-------
Copies of this report are available from the cooperating agencies listed on
the cover of this report and from the National Center for Air Pollution Control,
1055 Laidlaw Avenue, Cincinnati, Ohio 45237.
-------
FOREWORD
The Interstate Air Pollution Study was divided into two phases. Phase I, a
general study of the overall air pollution problems in the St. Louis - East St. Louis
Metropolitan area, was conducted to determine specific activities that would re-
quire further study in Phase II of the project. The effort -was divided into two
phases to provide a logical stopping point in the event that interest and resources
for proceeding further might not materialize. The necessary impetus did continue,
however, and the Phase II operation was also completed.
The Phase I operation resulted in a detailed report, designed primarily for
use of the Executive Committee members and their agencies in making decisions
concerning the Phase II project operation. A Phase I summary report was also
prepared; it received wide distribution.
Numerous papers, brochures, and reports were prepared during Phase II
operations, as were some 18 Memorandums of Information and Instruction concern-
ing the project. All of these documents were drawn upon in the preparation of the
Phase II project report. The Phase II project report consists of eight separate
volumes under the following titles:
I. Introduction
II. Air Pollutant Emission Inventory
III. Air Quality Measurements
IV. Odors - Results of Surveys
V. Meteorology and Topography
VI. Effects of Air Pollution
VII. Opinion Surveys and Air Quality Statistical Relationships
VIII. Proposal for an Air Resource Management Program
111
-------
CONTENTS
GENERAL CLIMATOLOGY 1
TOPOGRAPHY 1
METEOROLOGICAL PARAMETERS 1
Stability 1
Wind 3
Winds Aloft - 1,100 Feet Above St. Louis 3
AIR POLLUTION CLIMATOLOGY 3
URBAN AND TOPOGRAPHIC EFFECTS 15
Urban Heat Island Effects 15
Topographic Effects 19
METEOROLOGICAL INSTRUMENTATION IN THE ST. LOUIS AREA .... 21
RESEARCH ASPECTS OF THE STUDY 21
Tracer Studies 23
REPRESENTATIVENESS OF METEOROLOGICAL
CONDITIONS DURING THE SURVEY 31
Surface Wind 31
Wind Data for Pollution Roses 34
Temperature 38
Precipitation 39
Visibility 39
SUMMARY 40
REFERENCES 41
SUPPLEMENTARY READING LIST 42
DATA SOURCES 42
-------
V. METEOROLOGY AND TOPOGRAPHY
GENERAL CLIMATOLOGY
The St. Louis area experiences the meteorological conditions typical of most
Great Plains cities that are not influenced by major natural features such as moun-
tains or large bodies of water. The winters are fairly brisk and stimulating as a
rule and are seldom severe. Almost every winter has several periods of mild
weather and occasional short spells of extreme cold. Summers are generally
warm, whereas spring and fall are characterized by moderate temperatures.
Marked variations in day-to-day conditions are provided by changes from
warm, moist air flowing up from the Gulf of Mexico during some periods to cool,
dry air from the Northern Plains during others.
TOPOGRAPHY
The St. Louis area is gently rolling, generally with gradual undulations rather
than sharply defined ridges and valleys. Although there are a few rises and drops
of 100 feet in elevation over a short distance, the area within a 25-mile radius of
downtown St. Louis is generally free of major orographic features that strongly in-
fluence meteorological variables. In general, elevations range from 480 feet above
sea level in the downtown St. Louis area to about 550 feet at Lambert Field, 12
miles away, with a slight ridge rising to 600 feet in between. A flat area known as
the American Bottoms, surrounded by a crescent-shaped bluff rising to an average
of 640 feet above sea level, lies on the east side of the Mississippi River across
from St. Louis. The boundary bluff extends from Alton, Illinois, on the north, to
10 miles east of the Mississippi at East St. Louis, to within 3 miles of the river
opposite the mouth of the River des Peres on the south.
The average elevation of the Mississippi River is 400 feet above sea level, and
of the American Bottoms, about 420 feet above sea level, about 60 feet below the
main commercial area of St. Louis. At times, stagnation of a shallow pool of cool
air in this basin during the night enhances radiation fog formation under clear skies
in the early morning. These conditions are generally dissipated within a few hours
after sunrise. Similar conditions exist in the Missouri River channel to the -west
and north of St. Louis, though the Missouri River bottom area is relatively small
in extent.
METEOROLOGICAL PARAMETERS
Stability
Stability may be simply described as resistance to change. In the atmosphere
it maybe measured by the vertical variations (lapse rate) of temperature. Be-
cause of the interaction of pressure, temperature, and volume, a parcel of air
-------
lifted through the atmosphere experiences an increase in volume (hence a decrease
in density) and a decrease in temperature. If the parcel is insulated from its sur-
roundings or is moved quickly enough to prevent exchange of heat with its surround-
ings, its temperature decreases at the rate of 5. 4°F for each 1, 000-feet increase
in elevation (0. 98°C for each 100 meters). This condition is termed the adiabatic
lapse rate. If, when released at its new position, the air mass is warmer than its
surroundings, it continues to rise. If it is cooler than its surroundings it will tend
to descend. If this tendency to rise or descend is such as to return the air mass to
its level of origin, the atmosphere is stable; but if the tendency is to move it farther
from its level of origin, the atmosphere is unstable. Thus, if the temperature in
the atmosphere decreases with height more rapidly than the adiabatic lapse rate,
the atmosphere is unstable.
If the temperature decreases less rapidly or even increases with height, the
atmosphere is termed stable. Special terms are applied to these conditions. A
decrease of temperature with height more rapid than adiabatic is described as
super adiabatic and is an unstable condition. A decrease of temperature at the
adiabatic lapse rate is called adiabatic, of course, and is a neutrally stable condi-
tion. A condition wherein the temperature does not vary with height is termed
isothermal (iso means equal) and is quite stable. An increase of temperature with
height is an inversion, which is most stable. Conditions between adiabatic and
isothermal are sometimes called "lapse" or slightly stable. Each of the terms
"superadiabatic, " "lapse," and "inversion" covers a range of conditions. The
boundaries separating these ranges are the adiabatic and isothermal conditions.
These variations in lapse rate and stability are illustrated in Figure 1.
1000
500
UJ
i r i r
UNSTABLE
STABLE
cr
LJ
I
I
VERY STABLE
-6 -5 -4 -3 -2 -I 0
TEMPERATURE,°F
Figure 1. Lapse rates and stability.
-------
A stable condition inhibits the creation of eddies and thus the diffusion of air
pollutants, whereas an unstable condition supports the creation of eddies and ac-
celerates the diffusion of air pollutants. These effects of variations in stability
may be seen in smoke plumes, as illustrated in Figure 2.
Wind
The term "wind" includes both direction and speed. The principal effect of
wind direction is readily apparent since it determines the part of a city that may
be affected by the transport of pollution from given sources or areas. Wind speed
and atmospheric stability largely govern the degree of dilution of effluent before
reaching a given location downwind from a pollution source. Figures 3 through 6
are surface wind roses for particular months which characterize each of the four
seasons. The radial bars on the wind roses indicate the direction from which the
wind blows; for example, the southeast bar represents the wind that blows from the
southeast. Figure 7 illustrates monthly average wind speeds at the surface and at
1, 100 feet above St. Louis (500 meters above sea level) during the years 1950-1959,
as well as seasonal average wind speeds within this layer.
Winds Aloft - 1, 100 Feet Above St. Louis
The wind roses in Figures 8 through 15 for 500 meters above mean sea level
(1, 100 feet above St. Louis) were prepared from Weather Bureau pilot balloon
(PIBAL) observations at Lambert Airport. * Again the radial bars on the wind
roses indicate the direction from which the wind blows. This level was considered
high enough to be generally uninfluenced by any surface features, and thus to
present a picture of smooth airflow over the area. During the -winter months,
1, 100 feet is generally near the top of the mean maximum mixing layer and the
airflow does not show very much diurnal variation in speed or direction; however,
during the other months, turbulence from surface heating changes the wind regime
with time of day so that at this level daytime wind speeds are generally lower than
nighttime speeds.
AIR POLLUTION CLIMATOLOGY
The general weather conditions and climatology that have specific application
to this study are summarized in Figures 16 and 17. Table 1 summarizes and
compares several climatological parameters for St. Louis as well as other large
cities.
The principal effect of temperature on air pollution is that space heating is
required in cold weather. Heating requirements are measured in degree-days.
The heating degree-day is based on the premise that when the daily mean tem-
perature falls below 65 °F, space heating is generally required. The number of
heating degree-days is defined as the number of degrees the mean temperature is
below 65 °F. Emissions from space-heating equipment are very nearly proportional
to the number of degree-days; hence, degree-day data may be used to estimate
daily and seasonal variations of pollutants emitted from such sources.
The annual distribution of degree-days is presented in Figure 16 with the
monthly average maximum and minimum temperatures. Also presented in Figure
16 are the average number of days with thunderstorms, average number of days
-------
WIND
.
TEMPERATURE
UNSTABLE CONDITION (LOOPING)
TEMPERATURE
MODERATELY STABLE CONDITION (CONING)
TEMPERATURE
VERY STABLE CONDITION (FANNING)
TEMPERATURE
STABLE BELOW, UNSTABLE ALOFT (LOFTING)
TEMPERATURE'
UNSTABLE BELOW, STABLE ALOFT (FUMIGATION)
Figure 2. Schematic representation of stack gas behavior
under various conditions of vertical stability
(Dry adiabatic lapse rate shown by dashed line).
-------
Figure 3. January surface wind SPEED CLASSES Figure 4. April surface wind rose
rose for Lambert Airport, CALM^-«=BHZZF for Lambert Airport,
1951-60. 0-3 4-78-12 13.18-19 1951-60.
OCCURRENCE,%
Figure 5. July surface wind rose
for Lambert Airport,
1951-60.
Figure 6. October surface wind
rose for Lambert Airport,
1951-60.
-------
25
23
O—O
AVERAGE 500-meter (M S L)
WIND SPEED , NIGHTTIME
AVERAGE 500-meter ( M S L )
WIND SPEED, DAYTIME
AVERAGE SURFACE WIND SPEED , ALL HOURS
AVERAGE WIND SPEED BY SEASONS,
SURFACE-TO-500-meter LAYER
M A M J J A
MONTH
N
Figure 7. Wind speeds at Lambert Airport, averages for 1950-59.
measurable (0. 01 inch or more) precipitation, and the normal monthly amount of
precipitation. Thunderstorm days are of interest since a thunderstorm is associated
•with unstable conditions and strong vertical motions, which are effective in carrying
pollutants aloft. Precipitation alone is less important, though there is some ten-
dency for rain (or snow) to -wash (or scour) pollutants out of the atmosphere. The
number of thunderstorm days is greatest in the summer season. Spring and early
summer are the best seasons for removal of pollutants from the atmosphere by
wash-out, in view of the high number of days with rain.
Stability in the lowest layer of the atmosphere varies in a diurnal pattern,
normally being stable at night and unstable in the afternoon. The height to which
the unstable layer develops is defined as the maximum mixing depth, and, taken
with wind speed, represents a volumetric indication of the dilution of air pollutants,
since the scale and applications are generally area-wide. Holzworth has computed
mean maximum mixing depths from vertical temperature profiles (from radiosonde
observations) for all places in the United States -where data were available. These
•were interpolated for St. Louis from his maps (since the nearest radiosonde station
to St. Louis is Columbia, Missouri). Figure 17 shows the monthly mean maxi-
-------
Figure 8. January wind rose
1, 100 feet above surface at
Lambert Airport, daytime,
1950-59, 504 observations.
SPEED CLASSES Figure 9. April wind rose 1, 100
feet above surface at Lambert
Airport, daytime, 1950-59,
540 observations.
i
OCCURRENCE,%
Figure 10. July wind rose 1,100
feet above surface at Lambert
Airport, daytime, 1950-59,
440 observations.
Figure 11. October wind rose
1, 100 feet above surface at
Lambert Airport, daytime,
1950-59, 578 observations.
-------
„. ITT • j
Figure 12. January wind rose
1,100 feet above surface at CA
Lambert Airport, night-
time, 1950-59, 496
observations.
SPEED CLASSES
>-=«=>
0-34-78-12 13-18*19
mph
20 30 40
Figure 13. April wind rose
1, 100 feet above surface at
Lambert Airport, night-
time, 1950-59, 523
observations.
Figure 14. July wind rose 1,100
feet above surface at Lambert
Airport, nighttime, 1950-59,
502 observations.
Figure 15. October wind rose 1, 100
feet above surface at Lambert
Airport, nighttime, 1950-59,
568 observations.
-------
j 'NOIlVlldlDBMd
o o o o o o
m p m p in p
^f ^-' ro ro e\i oj
o o o o
m o m o
--do
o
I
0.
o
•g
cr
UJ
m
5
o:
w
o
— v>
M
S fe
^ 15
t 3
*S's i S^
"i Q a: uj o
Ib
_ <
evi —
— o
SAVQ
ooooooooooo
Ooor~-iBin
-------
Mduu'Q33dS QNIM
39V83AV
OJ —
O) 00
•Illllllllllllllllllllllll
>
0 D
Y/////////////////M^
I 1 1 I I I
oooooooo oooooo
tom^-focvj — oo> oo N (o m ^j- to
fi
o
a
i—i
0>
10
0)
t)
C!
fX
N ID m ^- ro
punojD
'Hld3Q 9NIXIW WflWIXVIfl NV3IAI
10
-------
Table 1. CLJMATOLOGICAL NORMALS FOR ST. LOUIS
AND FOUR OTHER LARGE CITIES
City
St. Louis
Chicago
Atlanta
Denver
Dallas
Temperature, °F
Mean
maximum
66. 0
59.3
72. 2
63. 5
76. 6
Mean
minimum
46. 6
40.8
52.2
36. 1
56.4
Record
high
115
105
103
105
111
Record
low
-23
-23
- 9
-30
- 3
Degree-
days
4699
6310
2826
6132
2272
Yearly
precipi-
tation,
inches
36.80
32.72
49. 16
14. 20
34.42
Cloud
cover
(tenths)
6.0
6.2
5.7
5.2
5. 1
Mean hourly
wind speed,
mph
9.3
10. 1
9.6
9.6
10.8
Percent
possible
sunshine
56
58
60
69
66
mum mixing depths for St. Louis associated with the average wind speed and with
the number of hours visibility at Lambert Field is restricted to less than 7 miles.
The large monthly variations in mixing depth are quite evident, -with lowest values
during the season of maximum heating. The combination appears to be related to
restricted visibility.
The product of maximum mixing depth and average monthly wind speed at or
near the surface gives a qualitative idea of atmospheric dilution for an area.
Table 2 illustrates this idea for the St. Louis area by using the average wind speed
from the surface to 1, 100 feet above ground. This concept indicates that the
atmosphere is least able to dilute pollutants during the fall and winter season when
dilution is most necessary, though its application is limited to afternoon conditions.
The wind rose in Figure 18 illustrates the wind directions associated with
visibility of less than 3 miles at Lambert Airport due to all causes during 1941-
1950. Visibility restrictions to less than 3 miles were present in 11 percent of
the weather observations during this 10-year period at the airport. Since fog is
normally associated with the lower wind speeds, it appears that visibility of less
than 3 miles attributable to nonfog conditions, primarily smoke and haze, occurs
most frequently -with -winds coming from the general direction of the city of
St. Louis (from the southeast) and Granite City (from the east-southeast or east).
The frequency of such visibility restrictions -with -winds from the east-southeast is
about twice that expected from examining the surface wind roses (Figures 3, 4,
5, 6).
Frequency of temperature inversion is another useful clirnatological parameter
for describing atmospheric dilution. Hosier's^ data in Table 3 show seasonal per-
cent frequency of inversion at or below 500 feet above ground. The percentage of
total time during which inversions occur is highest in fall; therefore, the time
during which pollutants can mix freely into a deep layer is a minimum during the
fall. The very high frequency of nighttime inversions in summer and fall suggests
that early morning pollutant levels will average much higher than early evening
levels. Figures 19 to 22 illustrate the percentage of low wind speed classes
(7 mph or less) recorded at 9 p.m. and 3 a.m. at the surface and are typical of
conditions beneath an inversion. These low wind speeds show the poor dilution
capabilities near the surface at night, especially -when considered -with the high
inversion frequencies in summer and fall. Also, morning fumigation conditions
occur when pollutants aloft in stable layers of air are mixed down-ward by turbulence
11
-------
Table 2. ATMOSPHERIC DILUTION FACTOR
Month
Dec.
Jan.
Feb.
Mar.
Apr.
May
Jione
July
Aug.
Sept.
Oct.
Nov.
Average
wind speed, mph
15.8
16.2
16.8
17.4
17. 1
15. 1
13.7
12.3
12.2
14.2
15. 1
15.6
Mean
maximum
mixing height,
meters
460
460
530
1, 000
1, 060
1,200
1, 040
1,400
1,250
1, 000
800
700
Product
(mph x
meters)
7,400
7,400
8, 900
17,400
18, 100
18, 100
14,400
15, 200
14,200
12,800
10, 900
Seasonal
product
average
Winter,
7,900
Spring,
17,900
Summer,
15, 600
Fall,
12, 600
Relative
dilution
factor
1.0
2. 3
2.0
1.6
Table 3. PERCENT FREQUENCY OF INVERSION OCCURRENCE
AT COLUMBIA, MO.
Season
Winter
Spring
Summer
Fall
9 p. m. 9 a. m. 6 p. m. 6 a. m.
(Central standard time)
53
54
84
80
38
4
5
24
27
1
5
20
52
67
78
66
Totala
time
31
31
35
43
Maximum
61
62
86
85
Percent total time.
Percent of dates on which at least one observation showed an
inversion.
12
-------
N
W
OCCURRENCE,%
Figure 18. Wind rose for visibility of less than 3 miles from all causes at
Lambert Airport, 1941-50.
from surf ace-heating and ground-pollutant concentrations are increased considerably
for 1 to 2 hours.
Interpolation from Korshover's -work, indicates that St. Louis experienced
nine cases -when high pressure systems -with very low wind speeds stagnated over
the area for 4 or more consecutive days during the period 1936-1956. These
cases resulted in 40 stagnation days, which occurred from April through October.
Such stagnation days are usually associated with low -wind speeds and restricted
vertical diffusion.
Air pollution potential is defined as a set of weather conditions conducive to
the accumulation of air pollutants in the atmosphere over a period of time. It is
a condition that can be forecast -with reasonable confidence when applied to large
areas and a reasonable persistence. Miller and Niemeyer indicate that Z high
13
-------
Figure 19. Winter low-speed
surface wind roses, 9p.m. CALM
and 3 a. m. , Lambert
Airport, 1951-60.
SPEED CLASSES
Figure 20. Spring low-speed
surface wind roses, 9 p.m.
'o-S4-T8..ziS-i8>.8 and 3 a-m> > Lambert
Airport, 1951-60.
OCCURRENCE,%
Figure 21. Summer low-speed sur-
face wind roses, 9 p.m. and
3 a.m., Lambert Airport, 1951-60.
Figure 22. Fall low-speed surface
wind roses, 9 p.m. and 3 a.m. ,
Lambert Airport, 1951-60.
14
-------
air pollution potential days occurred in St. Louis from August I960 through July 1961.
Their criteria for high air pollution potential are: (1) surface wind speeds less than
8 knots, (2) winds at no level below 500 mb (about 18, 000 feet) greater than 25 knots,
(3) the existence of subsidence below 600 mb (about 14, 000 feet), and (4) persis-
tence of these conditions for 36 hours or more over a minimum area equivalent
to a 4-degree latitude - longitude square. Since July, 1961, these criteria -were
met only for a 3-day period, November 30 - December 2, 1962, and for 1 day in
October 1964, when St. Louis was on the boundary of such an area on the 15th and
16th. Forecasts of high air pollution potential areas are issued daily over the
Weather Bureau Service C teletype circuit by the Weather Bureau Research Station
in Cincinnati, Ohio, and may be obtained from the Meteorologist-in-Charge at
Lambert Airport,
URBAN AND TOPOGRAPHIC EFFECTS
Urban Heat Island Effects
Metropolitan areas impose their own effects upon the atmosphere. The city
acts as a heat island, or heat reservoir, by storing up heat by absorption from the
sun's rays during the day and releasing the stored heat at night. The heat island
has two direct effects. Nighttime temperatures remain higher than in the surround-
ing countryside; and the nighttime inversion, which generally is based at the ground,
is lifted to some distance above ground over the city itself. St. Louis is no ex-
ception to this rule. The heat island effect is illustrated in Figures 23 through 26,
in which the average minimum temperatures for each of 4 months are mapped for
several sites in and around the city. Note that in each case the minimum tempera-
ture at the KM OX-TV tower averages higher than at any of the outlying sites.
Table 4 illustrates the inversion effect; average early morning temperatures for
each of 4 months are given for various levels on the KMOX-TV tower. In each
case the average minimum temperature at 125 feet was lower than the average
temperature at 250 feet, and in three of the four cases, lower than the average
temperature at 455 feet. In July and April the average condition was an inversion
for both layers; in October, an isothermal layer above an inversion; and in January,
a stable (between neutral and isothermal) layer above an inversion.
Although the existence of these urban "heat islands" has been -well documented" ~ ^
and can be explained quite easily, their dimensions and total effect have not been de-
fined. When the multitudinous variations affecting them are taken into account, a
simple model likely to provide such information is not possible. Their vertical ex-
tent has been estimated' at about three times the average height of buildings, al-
though this may be suspect in the case of a small cluster of tall buildings such as
occurs in the downtown area of larger cities.
The factors involved in producing a heat island are many. Heat itself may be
supplied by absorption of solar radiation during the day and reradiation at night, or
by space heating during colder months. Low •wind speeds are essential if the thermal
stratification characteristic of a heat island is to be established and maintained. The
presence of buildings reduces -wind speeds. Clear skies intensify the effect since
radiation from the countryside permits rapid cooling at night -while radiation from
building walls reflects back and forth to be absorbed eventually by the air, perhaps
mostly by conduction from the •warm surfaces.
15
-------
SO Ut HO
Figure 23. Average minimum tem-
perature for July 1963.
Figure 24. Average minimum tem-
perature for October
1963.
HS-HAZELWOOD SCHOOL SP-STATE POLICE STATION
LA-LAMBERT AIRPORT KT-KMOX-TV TOWER
LS-LINDBERG SCHOOL fwEW-RADIO STATION (Oct only)
A OBSERVED MINIMUM TEMPERATURE AT 125ft ABOVE
GROUND
B. REDUCED TO GROUND LEVEL USING AVERAGE LAPSE
RATE 125 TO 250 ft
C. REDUCED TO GROUND LEVEL USING ADIABATIC
LAPSE RATE
500- SIO S!0 MO S«
Figure 25. Average minimum tem-
perature for January
1964.
Figure 26. Average minimum tem-
perature for April 1964.
16
-------
Table 4. EARLY MORNING MINIMUM TEMPERATURES
AT 125-FOOT LEVEL ON KNOX-TV TOWER
(Adiabatic Temperatures are Derived From 125-Foot Data
for Comparison With Observed Data at Other Levels)
Height above street
Temperature, °F
1963
July
Oct.
1964
Jan.
Apr.
455 feet Average, measured
adiabatic
250 feet Average, measured
adiabatic
125 feet Average, measured
125 to 250 feet
125 to 455 feet
31
26
23
16
21
19
20~
22
69. 5 60. 7 31. 1
66.0 58.6 29.7
69.3 60.7
67.1 59.7
67.8 60.4
52.9
50.6
31.7 52.7a
30.8
31.5
51.7
52.4
Number of Inversions
Data from 1 day •were missing.
The heat island itself may be described as a "bubble" of air with a neutral to
isothermal lapse rate or weak inversion inclosed in a general inversion, with the
inversion layer deep enough to inclose the entire bubble. This is a subjective
description, illustrated in Figure 27, and should be verified when possible by
actual measurements. Some such measurements are available, but are not
o
sufficiently detailed for a definite description.
The circulation within the heat island itself must be described by inference
12
since suitable measurements are not available. Arnold has already provided
a reasonable suggestion for the St. Louis area. The simplest model would be
based on two assumptions, (1) a symmetrical warm area, warmer at the center
than at the edges, and (2) no overriding wind flow. In this model the warm air
would rise in the central area, flow outward along the surface of the bubble, lose
heat to the surrounding atmosphere, sink to ground level at the outer edges, and
return to the central area along the ground from, all directions. This is also shown
in Figure 27. There would be some exchange with the surrounding atmosphere due
to mixing at the interface, but this would be minimal. This flow pattern •would
permit pollutants emitted in the central areas to eventually reach intermediate
areas from the opposite direction. In reality, variations in terrain and heat sources
(a factory might be a "hot spot") -would introduce many modifications to this pattern,
but it should be expected that pollutants emitted at almost any source within the
bubble would reach the central area, and that average concentrations of any pollu-
tant emitted within the bubble would increase •with time until the condition is
terminated or the source eliminated. A very light wind would perhaps distort the
bubble without destroying it.
Termination of such a heat island, or rather the effect of its closed circula-
tion, would come about either upon general warming of the surrounding area suf-
17
-------
n!
m
O
4->
C
B
cu
o
B
CUD
-.-I
^
o
,T!
CO
rt
0)
CD
SI
00
18
-------
ficient to create a neutral or unstable condition, or upon an increase in wind speed
sufficient to break down the interface between the more stable and less stable layers.
Topographic Effects
Topography also has an effect on weather conditions. Low-lying areas have
consistently lower minimum temperatures than surrounding hills. As air cools and
becomes more dense, it settles into low places. When low rural or suburban areas
are next to a metropolitan area, this effect becomes dramatic. The American
Bottoms across the Mississippi River from St. Louis, is such a low lying area.
Inversions in this area are of great frequency and intensity. This local effect has
been well discussed, for the fall season, by Dr. G. R. Arnold in his doctoral
dissertation. ^
Dr. Arnold set up an observing site for both temperature and wind at the WEW
radio transmitter site, bet-ween East St. Louis and Caseyville, Illinois, about 5
miles east of the Mississippi River, and made observations from September 6 to
December 6, 1963, inclusive. During this period there were only six dates on
which no inversion -was detected in observations made at either dawn or dusk.
Ten-degree or greater inversions (where the temperature aloft was at least
10°F warmer than at the surface) occurred on 45 percent of the mornings and
15°F inversions, on 25 percent of the mornings. On one occasion an inversion of
27 °F was measured at dawn, and on another, a 17°F inversion was measured at
dusk.
Most of these inversions •were represented by cold air in the Bottoms. The
elevation of the surrounding bluff and hills averages about 200 feet above the
Bottoms. Of all the inversions Dr. Arnold measured, about 81 percent of the
average temperature increase noted at 500 feet occurred in the first 200 feet, or
•within the confines of the valley.
The minimum temperature at the WEW site averaged about 7°F lower than at
the Customhouse in St. Louis; only once was it as much as 3°F warmer, whereas
on 27 occasions it was 10°F or more colder. (December data were not included. )
Evidence of a "count erf low" (wind reversal) was found in both meteorological
data and soiling index measurements of suspended particulates. Although "There
are no principal sources of smoke either south or east of WEW, " by far the greater
number of soiling index samples showing high pollutant values were obtained -with
•winds from those directions. Visual observations of smoke from burning dumps
or open fires showed the counterflow also. Figure 28 is reproduced from Arnold's
treatise to illustrate the counterflow, which is similar to the heat island circulation
postulated above.
The juxtaposition of the cold pool of air in the American Bottoms and the heat
island of the City of St. Louis thus produces complex wind patterns, the effect of
which are to retain effluents in the city and bottom area during night and early
morning hours. Dr. Arnold presents seasonal evidence of a quasi-closed circula-
tion within these areas. Unfortunately year-round data are not available, but there
is little doubt that this condition occurs, in greater or lesser degree, in all seasons
of the year.
19
-------
O
s
B
•*->
o
PQ
rt
u
(U
s
fn
(1)
I-l
O
oo
(M
d
ao
I I
'13A31 V3S 3A08V NOI1VA313
20
-------
METEOROLOGICAL INSTRUMENTATION IN THE ST. LOUIS AREA
Figure 29 shows the location of'Weather Bureau Offices, Cooperative Climato-
logical Stations, and special meteorological instrumentation sites in the St. Louis
area. During the atmospheric dispersion field experiments, special equipment and
instruments were used to determine more accurately the character of the atmosphere
at low levels. Balloon-borne instruments were used to measure the variation of
temperature with height, and pilot ballons were used to measure the variation of
wind with height.
Table 5 lists the location of the Interstate Air Pollution Study meteorological
sites and the instrumentation at each.
RESEARCH ASPECTS OF THE STUDY
In connection with the Interstate Air Pollution Study, detailed dispersion studies
were conducted by the Meteorology Section, Laboratory of Engineering and Physical
Table 5. METEOROLOGICAL INSTRUMENTATION
FOR ATMOSPHERIC DIFFUSION RESEARCH STUDY
Location
KMOX-TV tower
Hazelwood High School
Missouri State Police Radio Tower -
Daniel Boone Expressway near
Ballas Road
Lindbergh High School
Forest Park
Height, ft
125
250
393
455
6
10 ft above
roof
6
50
6
10 ft above
roof
3
Instrumentation
Temperature sensor
Aerovane (wind direction
and speed)
Anemometer (speed only)
Temperature sensor
Anemometer (speed only)
Anemometer (speed only)
Temperature sensor
Aerovane
Anemometer (speed only)
Hygrothermograph
Aerovane
Hygrothermograph
Aerovane
Hygrothermograph
Aerovane
Fluorescent particle
dispensing equipment
21
-------
Location
1. Alton Dam No. 26.
2. E. St. Louis Airport
3. St. Charles
4. St. Louis River
Forecast Center
5. St. Louis University
6. Valley Park
7. Webster Groves
0. Lambert Airport
X. USWB City Office
A. KMOX TV Tower
B. Hazelwood High School
C. State Pol ice Radio Tower
D. Lindbergh High School
E. Forest Park
Instrumentation
Recording rain gauge and temperature
Precipitation and temperature
Recording rain gauge and temperature
Precipitation and temperature
Precipitation and temperature
Precipitation
Precipitation and temperature
Complete weather records
Complete weather records
Instrumented for air pollution study
Instrumented for air pollution study
Instrumented for air pollution study
Instrumented for air pollution study
Dispensing site for tracer study
Figure 29. Climatological stations and specially instrumented meteorological
sites in St. Louis area.
^
22
-------
Science, United States Public Health Service. The objective of this study was to
describe quantitatively the dispersion of material emanating from various locations
near and within an urban area, and to relate the dispersion to the causative
atmospheric flow and turbulence.
The dispersion studies were of two types involving different techniques. In
one study, fluorescent (tracer) particles •were released under various meteoro-
logical conditions and their dispersion over the downwind area -was measured. In
the other study, an inventory of sources of sulfur dioxide was made and the dis-
tribution of this pollutant over the city was measured and correlated with mete-
orological data.
Meteorological measurement sites in Figure 29 provided continuous data, which
has been reduced and placed on automatic data-processing cards. When these data
are combined with the tracer dispersion data, a mathematical atmospheric disper-
sion model can be developed. The model itself is an expression relating the vari-
ous pollution sources throughout the area, both by location and strength, and vari-
ous meteorological parameters (principally wind direction, wind speed, and sta-
bility to the distribution of pollutants). Once completed and tested, the model will
be useful in planning for the future, in estimating concentrations to be expected at
any place, and in estimating the effect of new sources or changes in existing sources.
Work is not yet completed on dispersion studies. When it is, separate tech-
nical papers and reports will be prepared.
Tracer Studies
Studies in which tracer materials are deployed in the atmosphere have been
conducted at various times and places over many years. From these studies,
atmospheric diffusion coefficients have been determined with a reasonable degree
of precision. Most of these studies have been over open and level countryside,
and their applicability to the relatively complicated features of an urban area is
not straightforward.
The initiation of the Interstate Air Pollution Study made it possible to conduct
tracer studies over an urban area at minimum expense because of the facilities
and equipment on hand. Additional meteorological instrumentation was installed
on the KMOX-TV tower downtown, at Lindbergh High School, Missouri State Police
Station C, and Hazelwood High School--all on the periphery of the urban area.
Samplers were placed along seven arcs centered on two release points, Forest
Park for use •with westerly •winds, and the Knights of Columbus Building at Grand
and Potomac for southeasterly -winds. These sites and the sampling arcs are
shown in Figure 30. Over 300 sampling sites •were selected; 30 to 50 were used
in each experiment. They included trees, utility poles, public buildings, residen-
ces, and commercial structures.
The tracer material used -was zinc cadmium sulfide, a fluorescent compound.
Particle diameters ranged from 0. 5 to 5 microns and averaged about 3 microns (about
1/10,000 inch). Particles of this size settle so slowly and respond so readily to ran-
dom molecular motions in the air that their dispersion may be considered the same
as that of a gas for studies of this type. Samplers were of three types: (1) roto-
rod samplers, consisting of an H-shaped collector rod kept spinning by a battery-
23
-------
LEG END
PARKS
AIRPORT
SAMPLING SITES
METEOROLOGICAL SITES
FOREST PARK
GRAND AND POTOMAC
AVENUES
Figure 30. Sampling site locations used in tracer study.
powered motor (uprights were about 1/70 inch broad and 1-1/5 inches high, of
metal -with a light coating of silicone grease, and spinning on a radius of about one
and one-fifth inches at 2, 400 rpm); (2) membrane filter samplers, in which air
is drawn through a membrane filter at a predetermined rate by an electrically-
powered vacuum pump; and (3) a drum pulsed-sampler, in which air is drawn through
a slit-orifice at a predetermined rate and impinges upon a metal drum (coated lightly
with silicone grease), which rotates by 3-degree steps at variable but controlled in-
tervals. The first two samplers provide estimates of total exposure to the cloud of
24
-------
particles (dosage), whereas the drum provides an estimate of the density of the cloud
at various times as it passes over the sampling point.
In addition to the fixed meteorological network (Figure 30), a wind recorder
•was operated and pilot balloon observations were taken at the tracer release site.
The wind recorder provided a continuous record of -wind speed and direction near
the ground, and the pilot balloon observations provided a measurement of the
vertical variation of -wind speed and direction at a particular time. Transponder-
equipped tetroons*' •were released from the tracer release site during each experi-
ment and followed by use of the Weather Bureau radar at Lambert Airport. Tet-
roons float at a predetermined height above ground and show visually •where a
parcel of air is going. Thus they enabled the research crew to follow the cloud
of invisible particles. The transponder is an electronic device that enables a
radar operator at a considerable distance to follow the tetroon by eliminating
interfering radar echoes from buildings and other fixed objects. The radiosonde
provides a record of the rate at which temperature and relative humidity change
•with altitude, and thus an estimate of atmospheric stability at the time of observa-
tion. Other meteorological data were obtained during many releases by radiosonde
ascents, either free or tethered from the roof of the Federal Building at 12th and
Market Streets. Tethered balloons were also used to carry Rotorod samplers to
elevations of about 1, 000 feet to obtain vertical profiles of the tracer cloud during
17 releases.
Seven series, totaling 43 experiments, were conducted between May 1963 and
March 1965.
Limited assays of the sampling results •were made during each test series to
correct any obvious deficiencies in the sampling layout or procedures. After each
test series, all samples -were sent to Metronics, Inc. in Palo Alto, California, for
actual sample assay. From 3 to 6 months was required to complete the sample
counting and checking. These assay results, expressed as number of particles per
sample, •were analyzed together •with the meteorological data to determine the dis-
persion patterns obtained under various meteorological conditions.
Examples of the results for two quite different conditions •were selected for il-
lustration. The ninth experiment, a release from Forest Park, was run during
midday on September 12, 1963. The wind was blowing steadily and briskly from the
northwest, and the pattern of concentrations •was the reasonably familiar elongated
ellipse (Figure 31), with the concentrations decreasing rapidly with distance from
the source. In this case, all the various measurements of wind direction (the three
outlying sites, two levels on the KMOX tower, the pilot balloon observations, the
surface •winds recorded at the release site, and the tetroon trajectory) were within
15 degrees of the mean direction of the tracer. The measured wind speeds, allow-
ing for local differences due to differing instrument exposures, were also consis-
tent and gave a good indication of the speed of travel of the tracer. Figure 32 shows
the cross-plume concentration of particles in this experiment. The mean path of
the tetroon clearly indicates the centerline of the cloud of particles. Figure 33
shows the time required for the cloud of particles to reach each sampling arc in the
same experiment, and the duration of its passage at each arc. These data are
from specific drum-type samplers, and the multiple peaks shown for the first two
samples are undoubtedly clue to the shifting of the cloud pattern jn fluctuating winds.
The time required for the tetroon to reach the sampling arc corresponds well -with
the time at which measurable concentrations were first in evidence.
25
-------
SEPTEMBER 12, 1963, 1215-1315 C.D.T.
TRACER RELEASE
3XIO~'° Lower limit of significant data
FOREST
PARK
N
A
X 10
- 10
-10
3XIO~9
- 8
Figure 31. Pattern of relative concentration, in grams per cubic meter, for a
daytime tracer experiment with steady winds (Concentrations based on
emission rate of 1 gram per second).
To use dispersion data, a term must be found to describe the distribution of
pollutants in a cloud or plume. Such a term is the statistical standard deviation
(
-------
SEPTEMBER 12,1963, 1215-1315 C.D.T.
TRACER RELEASE
TETROON 1230-1330 C.D.T.
ARCS ARC-I
2, 3
LEGEND
• ROTOROD
+ MEMBRANE FILTER
* DRUM
120 130 140 150 160 170
AZIMUTH FROM RELEASE SITE, degrees
Figure 32. Crosswind relative dosage distributions along three sampling arcs,
and mean direction of tetroon travel.
27
-------
17.577
600
1,6 OO
1,400
SEPTEMBER 12, 1963
"0 10 20 30 40 50 60
TIME FROM FIRST ARRIVAL OF CLOUD AT SITE, minutes
Figure 33. Sequences of dosages at three sites at approximately the same azimuth
from tracer release site (Abscissa is adjusted for travel time to each
sampling site according to mean tetroon speed).
28
-------
SEPTEMBER 12,1963
1,000
o>
1
£500
o
<
UJ
Q
200
V)
100
TRAVEL DISTANCE, km
I
5 6
7 8 9 10
i i i i
4 6 8 10
TRAVEL TIME, minutes
20
Figure 34. Measured crosswind standard deviations (ay) and derived vertical
standard deviations (
-------
SEPTEMBER 18,1963, 2100-2200 C.D.T.
TRACER RELEASE
IXIO"9 Lower limit of significant data
N
HAZELWOOD HIGH
•- 2335
LAMBERT AIRPORT
2330
STATE PATROL.
- . 2315
GRAND AND
POTOMAC
LINDBERGH HIGH
2310
2305
Figure 35. Pattern of relative concentration, in grams per cubic meter, for an
evening tracer experiment with light and shifting winds (Arrows
indicate mean wind directions at meteorological sites during time of
tracer release. Thin solid lines indicate time when surface winds
shifted from easterly to southerly, interpolated from meteorological
sites).
30
-------
Two aspects of the travel of the tracer may contribute to this apparent "loss" of
material. First, an appreciable transport of the material within the southerly
flow aloft must have occurred before the cloud at the surface passed; the sampling
results indicate that the passage of the cloud aloft was of a duration comparable to
the transit time of the surface cloud. Second, the earlier portion of the tracer
release probably was carried westward around the end of the sampling arcs, and
subsequently was carried northward a few miles •west of the most distant arc, so
that very little dosage from this portion of the release was observed anywhere.
With such a complex pattern of flow, there is no "standard" diffusion equation
for which coefficients can be derived. Indeed, it is impossible to define a "mean
•wind direction" or a "mean •wind speed, " and it appears that the sampling results
rather poorly define the geometry of the entire tracer cloud. Weather situations
similar to this case are of more than routine interest, however, because situations
like this are the type that lead to high concentrations of air pollutants. Any at-
tempts to trace sources of pollutants with such a complex flow pattern are likely
to be frustrating and inconclusive.
REPRESENTATIVENESS OF METEOROLOGICAL CONDITIONS DURING THE
SURVEY
Since dispersion and, to some extent, emission of atmospheric pollutants are
strongly dependent upon meteorological conditions, in a study of air pollution levels
one must know whether meteorological conditions are representative of those usu-
ally encountered. With this knowledge one can estimate the concentrations that may
be expected under average conditions and under other conditions as •well.
Data used in the folio-wing discussion are from surface observations at Lam-
bert Field and from temperature sensors mounted on the KMOX-TV transmitting
tower in downtown St. Louis. Data are for the period beginning July 1, 1963, and
ending June 30, 1964.
Surface Wind
The average wind speed for the year of the study was 10. 0 mph, 0. 7 mph in
excess of the normal. Of 9 months showing an excess over normal, 4 were at
least 10 percent above, and 3 of these -were around 20 percent above normal. The
remaining 3 months were below normal, although in no case by as much as 10 per-
cent. The monthly variations of average -wind speed and the normal values are
shown in Figure 36. With the exception of March, April, June, and July, wind speeds
were such that average concentrations of pollutants for the month should be con-
sidered representative, as far as the effect of wind speed alone is considered.
For these 4 months, however, the measured values should be considered to be
below average.
Wind roses are shown for July and October 1963, and for January and April
1964 in Figures 37 through 40, which correspond to the normal roses in Figures
6, 5, 3, and 4, respectively. In each case an excess frequency of winds from the
southeasterly to southerly directions is noted, as is a deficiency in winds from the
northwesterly to northerly directions and, except in January, a lower than normal
frequency of calm hours. In many cases a greater-than-normal frequency of winds
of the higher speed groups can be noted. Since the east-to-west and west-to-east
31
-------
14
13
Q.
E
LJ
UJ
Q.
10
9
8
7
1 I
1964
NORMAL (ISS
J I
I ,--..
x"-NORMAL (1951-1960)
' i i i i
M
J J
MONTH
N
Figure 36. Average hourly wind speeds, Lambert Airport.
transport of pollutants is of interest because of the interstate air movement, the
normal wind roses and wind roses for the study period were compared by cardinal
sectors with some emphasis on the east and west sectors (Table 6). The frequen-
cy of all winds in these two sectors was very near normal except for deficiencies
in October 1963 (west) and January 1964 (east). The frequency of low wind speeds
(7 mph or less), however, was much below normal except for westerly winds in
January 1964; the frequency of speeds of over 7 mph was near normal for westerly
winds and appreciably above normal for easterly winds. Since pollutant concentra-
tions generally bear an inverse relationship to wind speeds, it appears that for
Table 6. RELATIVE FREQUENCY OF WIND BY DIRECTION AND SPEEDa
Direction
c
Speed
January 1964
April 1964
July 1963
October 1963
Calm
4. 1
0.2
0. 1
0.7
North
All
0.5
0.5
1.0
0.7
> 7
0.5
0.4
2.0
0.6
< 7
0.4
0.7
0.5
0.8
East
All
0.8
1.0
1. 1
1.1
> 7
1.2
1.3
1.8
1.4
< 7
0.3
0.4
0.6
0.8
South
All
1. 4
1.2
1.2
1.6
> 7
1.5
1.4
1.7
1.8
< 7
1.0
0.2
0.4
1.2
West
All
1.0
1.0
1. 1
0.7
> 7
1.0
1. 1
1.1
0.8
< 7
1.0
0.5
0.6
0.7
Tabular figures are the ratio of occurrences in the specified month to the average
number of occurrences in the same month during the period 1951 - I960.
"Directions are grouped by quadrants: N includes NNW and NNE; E includes NE
through SE; S includes SSE and SSW; and W includes SW through NW.
cSpeeds included are: All, all reported values not including calm; > 7, all occur-
rences of over 7 mph; and _< 7, all occurrences of 1 to 7 mph, inclusive.
32
-------
Figure 37. July 1963 surface
wind rose for Lambert
Airport.
Figure 38. October 1963
surface wind rose for
Lambert Airport.
Figure 39. January 1964 surface
wind rose for Lambert
Airport.
Figure 40. April 1964 surface
wind rose for Lambert Airport
33
-------
these 4 months, at least, east-west or •west-east transport concentrations should
have been below average.
In evaluating the wind roses for January and April, an additional factor must
be considered. On January 1, 1964, the method of recording wind direction at
airport stations •was changed from entry by compass directions to entry by tens of
degrees in azimuth. In adjusting these data, recorded for 36-directions, to the
16-point wind rose of previous data, a slight bias in favor of the cardinal direc-
tions (N, E, S, W) is introduced at the expense of adjacent directions. This bias,
however, is much too small to account for the excessive frequency of south •winds
in January and April, or of the west wind in January (Table 7).
Wind Data for Pollution Roses
Since atmospheric pollutants are carried by air currents, relating their occur-
rence or concentration to wind speed and direction is a common practice, usually
illustrated in the form of a "pollution rose. " When the site at -which -wind data are
obtained is considerably removed from either sources or receptors of air pollution
a question arises as to its applicability. In the Interstate Air Pollution Study,
measurements are available at Lambert Airport, Hazelwood High School, the State
Police radio tower on the Daniel Boone Express-way, Lindbergh High School, and
the KMOX-TV tower at two levels (Table 5). Of these only the airport location
can be considered permanent.
Of the five locations listed, the most centrally located is the KMOX-TV tower.
The two wind direction instruments on the tower are at 125 and 455 feet above
street level (Table 5). Unfortunately neither instrument produced a complete
record. For comparison with Lambert Field data wind roses for both levels on
the KMOX-TV tower were prepared for the months of July and October 1963 (Fig-
ures 37-40), and January and April 1964 (Figures 41-48). The months of October
and April are particularly deficient, with only 480 and 350 hours of data, respec-
tively, for the upper level and only 649 hours of data for the lower level in April.
The other data are complete enough, however, to provide a qualitative rose for
comparison. The two highest speed classes used for airport data are combined
into one for the tower data. The roses are generally similar with one pronounced
exception. Compared with October airport data, the lower tower level shows a
very marked excess of winds from west through north-west, and an equally marked
deficiency of winds from east-southeast through south.
A more detailed and valid comparison can be made by use of Table 7, where
total occurrences from each direction are expressed in percent of valid data for
each of the three records. Because of the method of recording data, a slight bias
is introduced. Lambert Airport data for July and October 1963 are recorded to 16
points; all other data used here are recorded to 36 points and converted to 16 points
by combinations that group three points into one for the cardinal directions and two
points into one for other directions. The presence of this bias should be recog-
nized, though its effects are small enough to be disregarded here.
Of more interest where very local circulations are concerned is a difference
in pattern between the two tower levels. For the 2 months with relatively complete
records, the lower level shows an excess of winds from the easterly quadrant and
a deficiency from the -westerly quadrant (Table 8). Though based on incomplete
34
-------
ft
w
•5
O
H
i
X
O
W
co 2
Q r
gn
U r3
W H
OH U
o
w
f-1 I
§§
Q DH
P £
h
O
cq
o
U
•8
H
vO
O--
'H
rH
ft
vO
0s
i — i
fj
rt
1-1
00
• — i
O
00
sO
l-H
1-5
"£
o
ft
«|H
n
CD
|
H
h
0
o
rH
• H
rH
D
>
O
H
O
ft
• H
1)
O
o
rH
• H
\
*
O
FH
(M r^-j f^J rO xO O*^ ^O CD co xO uo \o ^3 ^^ ^O r^l ^D
r-H rH i— ( r-H
O
(M
r^-
rH i — 1 ^
^) I-H f\] co "^t4 LO co i — i LO ro uo co r** o^ o co o o
(Nj i — 1 r— 1
co •— i o o «~H co oo ^* E — ^-O ^o "^ to f\j oo ^ r*-
r-t t-H r-H
o
$
"*&
^*
f*
J^rH^^O^CO^OO^^ g
r^ "^f CO ^5 »~^ "~H ^^ f\] CO CO t*~ CT^ »~H CO ^O CO CO >~ •*
^H (M f-H r-H
(S]
1 — 1
ro f^J rO ""H co Is* *^ LO sO t*** LO ^O "^ cO LO ^^ LO ^*
r-H i-H rH ^*
J LO "^ CO LO CO f\l CO LO OO CTV f\] LO fM OO O CO rH 0s-
rH i — 1 rH r-H CO
t-^ 0s OO ^f CO CO r-H rO f\J OO rH f\J OO CO O ' — 1 ^ O
,-H f\] ,—(
o
00
i-H i-H i-H *^h
rjLOLOCOLO^LOOOCOOOt^-OOf^lLOMtNJCOO
rH i — 1
£^ oo ^^ t*~ ^O LO ^^ ro *~-i r*J ^^ oo LO "*J"* co co co ^^
rH fM rH
r^ £H £H W H H CO CO CO CO CO r^ r^ ^ r^ S O
t-
1 — 1
00
to
fi
o
•H
-M
rt
r-H ^
n)
-------
Figure 41.
July 1963 wind rose
for lower level of
KMOX-TV tower,
734 observations.
Figure 42.
October 1963 wind
rose for lower level
of KMOX-TV tower,
739 observations.
MILES PER HOUR
20 40 60 80 IOO 120 140
^^mit^S^imm^f^imim^SSi
NUMBER OF OBSERVATIONS
I
Figure 43. January 1964
wind rose for
lower level of
KMOX-TV tower,
743 observations.
Figure 44.
April 1964 wind
rose for lower
level of KMOX-
TV tower, 649
obs ervations.
36
-------
Figure 46. October 1963 wind
rose for upper
level of KMOX-TV
tower, 480 obser-
vations.
Figure 45.
July 1963 wind rose
for upper level of
KMOX-TV tower,
731 observations.
MILES PER HOUR
20 40 60 80 100 120 140
S^J^t^2-—^J—-1
NUMBER OF OBSERVATIONS
Figure 47. January 1964
wind rose for
upper level of
KMOX-TV tower,
712 observations.
Figure 48.
April 1964 wind
rose for upper
level of KMOX-
TV tower, 350
observations.
37
-------
Table 8. NUMBER OF OCCURRENCES
OF WIND DIRECTION FROM EAST AND WEST
QUADRANTS, KNOX-TV TOWER
040° - 140°
220° - 320°
July 1963
Lower
215
138
Upper
182
164
Jan. 1964
Lower
89
268
Upper
36
299
data for the upper level, an even more pronounced excess of -west to northwest
and deficiency of south and south southwest winds existed at the lower level in
October 1963, according to Table 7. These effects are almost certainly due to
the presence of the city and its action as a heat source.
The value of a pollution rose is dependent upon both its purpose and the data
used in preparing it. To relate a specific source and a specific receptor, wind
data should be obtained in the immediate vicinity from an instrument so located as
to indicate motion between source and receptor. Even then, care must be taken to
avoid possible eddies induced by nearby buildings or strong heat sources. Wind
roses (Figures 41-48) and tabular comparisons (Tables 7 and 8) indicate that the
tower data are influenced by local effects. Whether these effects influence only
one or both levels cannot be determined from the data. The presence of the tower
itself creates eddies reflected in the records as erroneous direction and/or speed
information. These errors vary with both speed and direction and cannot be ac-
curately assessed. The instruments at Lambert Airport, on the other hand, are
well away from any terrain or heat island effects. In addition, the data are un-
interrupted and there is assurance of continued operation. The records should be
as representative of the general flow as can be obtained. Thus, for the overall
study, and for future reference, the use of Lambert Airport -wind data for con-
structing pollution roses is preferred.
Wind records from the other three locations are from temporary installations
and also have periods of missing data. In addition, they are no more centrally
located with respect to the areas of important sources and most affected receptors
than is the airport. They were intended for use in the tracer studies (as were the
KMOX-TV tower records); and although of possible application in a neighborhood
problem, they are not suitable for use for overall pollution roses.
Temperature
Monthly degree-day totals for the study period are compared with normal
totals in Figure 49. In most months of this study heating requirements appeared
to be near normal. In October, requirements were about 65 percent below normal;
however, December of 1963 was the coldest December of record in St. Louis, and
heating requirements were about 145 percent of the normal for the month.
38
-------
LJ
cr
100
80
60
cr
UJ 40
o.
20
0
MEAN MAXIMUM
MEAN MINIMUM
NORMAL
DEGREE-DAYS
SON
1963
D
1,400
1,200
1,000
CO
>-
800 Q
i
LJ
LJ
600 cr
LJ
Q
400
200
0
Figure 49. Monthly mean maximum and minimum temperatures, and monthly
normal degree-days at Lambert Airport from July 1963 through
June 1964.
Precipitation
Rain and snow are of interest in air pollution because of their effectiveness in
reducing the pickup of dust particles from the earth's surface by the wind. A
minor effect is the -washout or scrubout of some particulate by rain or snow as they
fall. Days with measurable precipitation and total monthly precipitation amounts
are shown in Figure 50. The number of thunderstorm days is also shown. The
occurrence of a thunderstorm signifies unstable air, usually at or near the surface,
and consequently good dispersion conditions.
The study year as a whole was below normal in all three categories, total
amount of precipitation, number of days with thunderstorms, and number of days
•with rain. The summer months were deficient in total precipitation and number of
days -with thunderstorms, -with September 1963 and May 1964 also deficient in days
•with rain. February, March, and April 1964, -were above normal in total precipita-
tion; April v/as the only month above normal in all three categories. Other months
•were near normal in days with rain and days with thunderstorms, but December 1963
and January 1964 -were both deficient in total precipitation.
Visibility
Visibility, the horizontal distance at which an object can be seen, is sometimes
used as an indicator of air pollution; however, the frequency of visibilities restricted
to less than 3 miles from all causes (including rain, snow, and fog) during the year
of study, was only 6 percent compared with a normal of 1 1 percent. During only
39
-------
6
5 -
O
c
O
s
I- 3
Q_
O
LJ
01
0
D DAYS WITH THUNDERSTORMS
• DAYS WITH PRECIPITATION
> 0.01 inch
20
15
10
O
en
LU
GO
N
D
JFMAMJ JASO
1964 1963
Figure 50. Monthly precipitation totals at Lambert Airport for July 1963 through
June 1964.
4 months, November, January, February, and March, did as many as 10 percent of
all hours show visibilities restricted to less than 3 miles by all causes. Thus
visibilities -would indicate that particulate concentrations were somewhat below nor-
mal at Lambert Airport.
SUMMARY
Inspection of Figures 36 and 49 indicates that 5 months of the period from July
1963 through June 1964 could not be considered representative. July, April, and
June were much above normal in wind speed, therefore, diffusion conditions for'the
respective months were better than average. With an average wind speed slightly
above normal and heating requirements much below normal in October, measure-
ments of pollutants resulting from space heating would be expected to be below
normal. Since space heating requirements are normally lower in October than in
winter months, this departure may not be significant in the total pollution loading of
the atmosphere. December, with an average wind speed slightly below normal,
•was much above normal in heating requirements and therefore in pollutants result-
ing from space heating. In all other months, both wind speed and heating require-
ments were near normal.
40
-------
REFERENCES
1. U.S. Weather Bureau. Winds aloft summary and parameters. 500M MSL.
1963.
2. U.S. Weather Bureau. Local climatological data supplements.
3. Holzworth, G. C. Estimates of mean maximum mixing depths in the contig-
uous United States. Monthly Weather Review, 92:235-242. May 1964.
4. U.S. Weather Bureau. Terminal Forecasting Reference Manual. Lambert -
St. Louis Airport. Jan. 1959.
5. Hosier, C. R. Low-level inversion frequency in the contiguous United States.
Monthly Weather Review, 89:319-339. Sept. 1961.
6. Korshover, Julius. Synoptic climatology of stagnating anticyclones. Robert
A. Taft Sanitary Engineering Center. Cincinnati, Ohio. SEC TR A60-7.
7. 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.
May 1963.
8. DeMarrais, G. A. Vertical temperature difference observed over an urban
area. Bulletin of the American Meteorological Society, 42:548-554.
Aug. 1961.
9. Duckworth, F. S. and Sandberg, J.S. The effect of cities upon horizontal and
vertical temperature gradients. Bulletin of the American Meteorological
Society, 25:198-207. May 1954.
10. Landsberg, H. E. The climate of towns in man's role in changing the earth.
Thomas, W.L. , Jr. ed. University of Chicago Press. 1956.
11. Mitchell, J.M., Jr. The temperature of cities. Weatherwise, 14(6):224-229.
Dec. 1961.
12. Arnold, G.R. Local inversions, air currents, and smoke pollution in Cahokia
Bottom. Doctor of Science dissertation. Washington University. St. Louis,
Missouri. June 1964.
13. Pack, D. H. Air trajectories and turbulence statistics from weather radar
using tetroons and radar transponders. Monthly Weather Review, 90:491-
506. Dec. 1962.
14. Hoel, P. G. Introduction to mathematical statistics. John Wiley and Sons,
Inc. New York. 1963. p. 74.
41
-------
SUPPLEMENTARY READING LIST
1. Barnum, D. C. The influence of several meteorological parameters on the
smokiness in the St. Louis area. St. Louis University. Thesis for M.S.
degree. 1962.
2. Hanson, D. M. and Koontz, I. A. A study of restrictions to visibility at
Lambert Field, St. Louis. (Preliminary report 1952) U.S. Weather
Bureau manuscript.
3. Murine, V. S. Atmospheric pollution and weather in the St. Louis, Missouri,
area. St. Louis University. Thesis for M.S. degree. 1952.
4. Schueneman, J. J. A report of the atmospheric concentrations of SO in
St. Louis - 1950. Industrial Hygiene Section, Division of Health. City of
St. Louis.
DATA SOURCES
U.S. Weather Bureau.
Climatography of the United States Number 30-23
(Summary of Hourly Observations 5 years 1950-1955)
Climatography of the United States Number 60-23
(Climates of the States - Missouri 1959)
Climatography of the United States Number 82-23
(Decennial Census of United States Climate 1951-1960
Climatic Summary of the United States - Supplement for
1931-1952 Missouri. Series Number 11.
Climatological Data (State of Illinois)
Climatological Data (State of Missouri)
Surface Wind Summary and Parameters (In preparation
at National Weather Records Center)
U.S. Environmental Protection Agency
Begion 5, Library (5PL-16)
230 S. Dearborn Street, Room 1670
Chicago, IL 60604
42
------- |