Basic Concepts in Environmental Sciences - Quick Reference

Acronyms
ACF
Actual Cubic Feet
ACFM
Actual Cubic Feet per Minute
BACT
Best Available Control Technology
BHP
Brake horsepower
BOOS
Burners Out Of Service
BP
Boiling Point
CAA
Clean Air Act
CAAA
Clean Air Act Amendments
CAM
Compliance Assurance Monitoring
CEMS
Continuous Emissions Monitoring System
Cgs
Centimeter-Gram-Second
DACFM
Dry Actual Cubic Feet per Minute
DSCFM
Dry Standard Cubic Feet per Minute
EPA
Environmental Protection Agency
ESP
Electrostatic Precipitator
FIP
Federal Implementation Plan
HAP
Hazardous Air Pollutant
IPA
Isopropyl Alcohol
ITEQ
International Toxic Equivalency Quotient
LAER
Lowest Achievable Emission Rate
LEL
Lower Explosive Limit
MACT
Maximum Achievable Control Technology
MCE
Mixed Cellulose Ester
NAAQS
National Ambient Air Quality Standards
NESHAPs
National Emission Standards for Hazardous Air Pollutants
NSPS
New Source Performance Standards
NSR
New Source Review
OFA
Overfire Air
OTAG
Ozone Transport Assessment group
OTC
Ozone Transport Commission
PSD
Prevention of Significant Deterioration
QA/QC
Quality Assurance/Quality Control
RAP
Reclaimed Asphalt Pavement
RTO
Regenerative Thermal Oxidizer
SCF
Standard Cubic Feet
SCFM
Standard Cubic Feet per Minute
SIP
State Implementation Plan
TEQ
Toxic Equivalency Quotient
U.S. EPA
United States Environmental Protection Agency
VOC
Volatile Organic Compound
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Conversion Factors

American Engineering System
equation 1-1

Heat
1 Btu = 252 cal

Length and Distance
equation 3-1
1 in. = 2.54 cm
1 ft = 30.48 cm
1 meter = 100 cm
1 meter = 3.2808 ft
1 mile = 5,280 ft

Mass
equation 4-1
1 lbm = 453.6 gm
1 lbm = 7,000 grains

Mole Equivalents
1 lb mole = 453.6 gm mole

Pressure
(at std. conditions, 68°F)

1 atm = 407 in. W.C. =
14.7 psia = 14.7 lbf /in.2=
760 mm Hg = 29.92 in. Hg =
101.325 kPa = 33.92 ft W.C.

Temperature
1°C = 1.8°F
°C = (°F 32)/1.8
°F = 32 + 1.8 (°C)
°K = 273 + °C
°K = °R/1.8
°R = 460 + °F
°R = 1.8(°K)

Viscosity
equation 8-1
1 micropoise = 10-4 cp

1 poise = 100 cp

Volume
1 mL = 1 cm3

1 liter = 0.03531 ft3

1 ft3 = 7.481 gal

1 ft3 = 28.32 liter

1 m3 = 35.31 ft3

Volume to Mass
1 mL of pure water = 1 gm

1 gallon of pure water =
8.34 lbm

1 ft3 of pure water = 62.4 lbm

Volume (Gas) @ STP
Volume of 1 lb mole of gas
@ STP = 385.4 ft3
(or 385 ft3 rounded)

Volume of 1 gm mole of ideal gas
@ STP = 24.04 liters
(or 24 liters rounded)
equation 9-6

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Numerical Constants

equation 1-1
equation 1-2
equation 1-3
equation 1-4

Density
Density of city water at standard conditions =
62.4 lbm/ft3 or 8.34 lbm/gal

Density of water at 4°C (39.2°F) is 1 gm/cm3

Dissociation
Constant of Water
Kw = 1 × 10-14 (moles/L)2

Universal Gas Constant, R
equation 3-1
equation 3-2
equation 3-3
equation 3-4
equation 3-5

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Symbols

English Symbols

SymbolDefinition

ASTP
Fan motor current at standard conditions
AActual
Fan motor current at actual conditions
ATotal
Total area of fabric filter bags
BHP
Brake horsepower (total power consumed by the fan)
Cc
Cunningham slip correction factor
Ce
Coefficient of entry
Cp
Pitot tube coefficient (usually assumed to be 0.84)
Cpx
Heat capacity of compound x at constant pressure
Conc. i(Dry)
Dry concentration of gas i
Conc. i(Measured O2)
Gas concentration at measured oxygen level
Conc. i(Std O2)
Gas concentration at standard oxygen level
Conc. i(Wet)
Wet concentration of gas i
c
Average speed of molecules
D
Diameter
DFan
Diameter of fan sheave
DMotor
Diameter of motor sheave
Dc
Diameter of a droplet
Dh
Hydraulic diameter for rectangular duct
Dp
Diffusivity of particles
dv/dy
Velocity gradient
dpa
Aerodynamic particle diameter
dpmin
Minimum diameter of particles in a particular size range
dps
Stokes particle diameter
d50
Diameter of a median-sized particle
d15.78
Particle size at 15.78% probability in a lognormal distribution
d84.13
Particle size at 84.13% probability in a lognormal distribution
E
Voltage
e
Base of the natural logarithm
g
Gravitational acceleration
gc
Factor used when converting between pounds force and pounds mass
H
Height of a geometric shape ("h" is sometimes used for cylinders). Also, enthalpy
H
Henry's law constant
h
Height of a cylinder. Also, height of a fabric filter bag
he
Hood entry loss
I
Motor current
K
Boltzmann constant
KI
Impaction parameter
Kw
Dissociation constant for water
L
Length of a geometric shape. Also, in the gas stream Reynolds number calculation: linear dimension (usually duct diameter).
MW
Molecular weight
MWAvg
Average molecular weight
m
Mass
NRe(g)
Gas stream Reynolds number
n
Number of moles
P
Pressure
PAbsolute
Absolute pressure
PActual
Gas pressure at actual conditions
PAtm
Atmospheric pressure
PAvg
Average pressure
PBarometric
Barometric pressure
PGauge
Gauge pressure (a relative pressure)
PRelative
Relative pressure
PSTP
Gas pressure at standard conditions
PTotal
The total pressure of a gas composed of different chemical compounds (the sum of the partial pressures of all component gases)
Pj
Pressure whose value equals j
PM2.5
Particulate matter less than 2.5 micrometers in diameter
PM10
Particulate matter less than 10 micrometers in diameter
pf
Power factor (phase relationship between current and voltage waveforms)
Q
Heat required per unit time. Also, volumetric gas flow rate.
R
Universal gas constant
RPMFan
Fan speed, revolutions per minute
RPMMotor
Motor speed, revolutions per minute
r
Radius
SP
Static pressure
Sp. Gr.
Specific gravity
SPh
Hood static pressure
T
Temperature
TAbsolute
Absolute temperature
TActual
Gas temperature at actual conditions
TAvg
Average gas temperature
TSTP
Gas temperature at standard conditions
Ti
Temperature whose value equals i
TP
Total pressure (the combined static pressure and velocity pressure)
t
Time
V
Volume
VT=i
Volume at a specific temperature (i)
V(T=i, P=j)
Volume at a specific temperature (i) and pressure (j)
VP
Velocity pressure
v
Gas velocity. Also, in the impaction parameter equation: difference in velocity
vt
Terminal settling velocity
W
Width of a geometric shape
W.C.
Water column
x
Mole fraction of pollutant in liquid phase
y
Mole fraction of pollutant in gas phase
y*
Mole fraction of pollutant in gas phase in equilibrium with liquid

Greek Symbols

SymbolDefinition

"Change in." For example T means change in temperature
Static pressure drop
Unit shearing stress between adjacent layers of fluid
Collection efficiency
Viscosity of gas or fluid at the prevailing conditions
3.1416
Density
Density at actual conditions
Density of a liquid at a specific temperature (x)
Density at standard conditions
Density at a specific temperature (i)
Gas density at a specific temperature (i) and pressure (j)
Density of water at reference temperature
Density of a gas or fluid
Density of a particle
Standard deviation of particle mass distribution
Kinematic viscosity
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Units of Measurement

Abbrev.Unit

ACFM
Actual cubic feet per minute
atm
Atmosphere
BHP
Brake horsepower
Btu
British thermal unit
°C
Degree Celsius
cal
Calorie
cm
Centimeter
cp
Centipoise
DNm3
Dry standard cubic meter
°F
Degree Fahrenheit
fpm
Feet per minute
ft
Foot
ft W.C.
Feet of water column
gal
Gallon
gm
Gram
gpm
Gallons per minute
gr
Grains
hp
Horsepower
in.
Inch
in. Hg
Inches of mercury
in. W.C.
Inches of water column
°K
Kelvin
kcal
Kilocalorie
kg
Kilogram
kPa
Kilopascal
L
Liter
lb
Pound
lbf
Pounds force
lbm
Pounds mass
m
Meter
mi
Mile
min
Minute
mm
Millimeter
mm Hg
Millimeter of mercury
M
Molarity
mPa
Millipascal
µg
Microgram
µm
Micrometer
Nm3/min
Standard cubic meters per minute
nm
Nanometer
N
Normality
Pa
Pascal
p
Poise
ppm
Part per million
ppm(v/v)
(Also ppmv) Part per million calculated as a ratio of the volume of the pollutant divided by the total volume of the sample
ppmvd
Part per million (dry basis)
ppm(w/w)
Part per million calculated as a ratio of the weight of the pollutant divided by the total weight of the sample
psi
Pounds per square inch
psia
Pounds per square inch (absolute)
psig
Pounds per square inch (gauge)
°R
Degree Rankine
rpm
Revolutions per minute
SCFM
Standard cubic feet per minute
sec
Second
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