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1

Literature Survey for Liquid Aerosol Release Data 

to Support Revised TPQ Methodology for EHS Solids in Solution

February 2008

1. DOE Aerosol Data for Aqueous Solutions

Source: DOE Handbook, Airborne Release Fractions/Rates and Respirable Fractions for 

Nonreactor Nuclear Facilities. December 1994 Vol. I and II.

Airborne Release Fraction= ARF

Respirable Fraction=RF DOE used a 10 μm Aerodynamic Equivalent Diameter (AED) 

to define respirable size. [(Note: EPA has a different definition for respirable size (< 4 

micron)] 

Airborne release rate = ARR, the fraction of the released material that has been deposited 

and then gets re-suspended over time.

Accident Scenarios- DOE evaluated experimental data and models for many different 

accident scenarios. The ARF values for the scenarios varied widely in order of 

magnitude, from 1E-1 to 1E-8. Because EPA is more concerned with those accidents 

with higher airborne release and to simplify the process of developing TPQs for aerosol 

type releases, only those DOE scenarios with of an estimated ARF 1E-4 or greater were 

considered for discussion below.

A. Thermal Stress from Boiling Bounding ARF = 2E-3 (0.002) 

Data was obtained from experiments involving boiling (bubbles continuously breading 

the surface of the bulk liquid with >30% of the volume of liquid as bubbles) of aqueous 

solutions in flowing air. Mishima, Schwendiamn and Radasch (1968) measured ARFs 

during the boiling of a dilute solution of plutonium nitrate. 100 mls of solution was 

placed in a 180 borosilicate beaker on a hot plate. Air and particulate material escaping 

from the beaker was drawn through a glass bell jar and an in-line glass fiber filter. 

Velocity through the filter was estimated to be 3 cm/s. Hot plate temperature varied from 

200-220 o C. Period of time heated varied from 42 to 66 minutes. The ARFs for the four 

runs at boiling ranged from 4.5E-7 to 1.8E-3.1 Three of the four values ranged from 3E4 to 1.8E-3. The two highest values were estimated by the sum of the filter acid lead and 

from acid washes of the equipment downstream of the filter position due to loss of filter 

(filter ruptured). These values included solution splattered on the vessel onto the 

glassware. Based on the experiment a bounding ARF value for boiling of aqueous 

solutions of 2E-3 was selected by DOE. 2 Twelve other studies were evaluated by 

Borkowski, Bunz and Schoeck (1986) that examined the airborne release of bubble-burst 

at the surface of aqueous solutions. The ARFs of 2E-3 measured by Mishima, 

Schwendiman and Radasch (1968) bounds the value measured by the other reported 

studies by approximately an order of magnitude. 

 

1

1994 DOE V. I, pg. 3-13

2

 1994 DOE V. I, pg. 3-1
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Particle size analysis:

Particle size was not measured in Mishima, Schwendiamn and Radasch (1968). 

In one of other studies evaluated, Garner et al. (1954), measured drop size distribution 

and total entrainment during evaporation in vessels of various diameters (4-in and 12-in. 

diameters tubes). Although ~95% of the drops were in the <20 μm diameter range, the 

total mass entrained was primarily due to drops > 100 μm diameter. Entrainment values 

were in the 1E-5 range.3 Bubbling experiments conducted by Heger et al. (1982, 1983) 

created airborne drops that were bimodally distributed with maxima at 0.3 and 0.8 μm 

diameter. 4Entrainment values ranged from 1E-7 to 1E-4. Adding tributyl phosphate 

reduced the surface tension and increased entrainment by a factor of 5 to 10. This also 

increased the generation of larger diameter drops. 

B. High Pressure Venting Below Liquid Level Bounding ARF 0.12

Releases from venting pressurized liquids can range from pinhole leaks in pipes 

(generating a mist), to drips from very slow leaks to large jets of liquids that may gush 

from large holes. The amount and aerodynamic size distribution of the spray generated 

are a function of the size and characteristics of the breach, the upstream pressure, and the 

liquid characteristics (e.g. viscosity, density, volatility). 

For purposes of airborne suspension, a conservative assumption would be the pressurized 

release of the liquid via a very fine hole as occurs in a commercial spray nozzle. The size 

distribution of aerosol releases from some commercial spray nozzles as a function of 

orifice diameter (0.063” to 0.128”) and upstream pressure (50-200 psig) were shown by 

Mishima, Schwendiman and Ayer (1978).5 The size distribution of the liquid drops 

decreases with orifice diameter and increasing upstream pressure. Figure 3-4 in DOE 

Volume 1 Handbook shows cumulative mass fraction vs. droplet diameters range from 

1E-4 to 8E-1 (0.0001 to 0.80). The droplet diameters range from 7 to 500 μm. 6

It is not anticipated that drops form from breaches, cracks, leaks would generate finer 

drop size distributions than equipment specifically designed for that purpose. Therefore, 

values from the 0.063” orifice diameter run at 50 psig were used by DOE to assume a 

bounding ARF value of 1E-4 for aerosol sizes ≤ 10 μm. While DOE was focused on 

finding ARF values for only respirable fractions, EPA should be looking beyond that. 

Figure 3-4 shows that at aerosol size ≤100 μm, the cumulative mass fraction varies from 

3E-2 to 1.2E-1 (0.03 to 0.12) depending on the experiment run.7 Therefore a bounding 

value of 1.2E-1 (0.12) is expected for aerosol diameter sizes ≤100 μm. Note that 

although the x-axis of Figure 3-4 is labeled cumulative mass fraction, it appears the data 

in the table is actually cumulative mass percent. Therefore values cited from the Figure 

3-4 have been divided by 100 to obtain the mass fraction.

 

3

 1994 DOE, V. I, pg. 3-15

4

 1994 DOE, V.I, pg. 3-15

5

 1994 DOE. V.I, pg 3-20

6

 1994 DOE. V.I, pg 3-20 and 3-21

7

 1994 DOE. V.I, pg 3-21
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Data for Aerosol Releases from Pressure Venting Below the Liquid Level (50-200 psig)

Cumulative 

mass fraction 

airborne 

For aerosol 

diameter, 

μm

0.003 - 0.0001 ≤ 10 μm

0.03 - 0.12 ≤100 μm

C. Pressure Venting above the liquid level Bounding ARF 2E-3 (0.002)

Sudden depressurization of a liquid allows the release of dissolved/trapped gases. This 

sudden release of gases may result in bubble formation that can create very small drops 

upon collapse. The drops can be carried with the venting gas. Experiments were 

performed to measure the ARF due to venting pressurized volumes of aqueous solutions 

(uranine and UNH) in quasi-equilibrium with their pressurizing gases (Sutter, August 

1983). 

100 cm3and 350 cm3of uranine (sodium fluorescein) and UNH (uranyl nitrate 

hexahydrate) solution were released at three pressures of 50, 250 and 500 psig. The 

solution densities were 0.99 g/cm3for uranine and 1.54 g/cm3for UNH. An 800 cm3

volume container fitted with rupture discs, which rupture at a specified pressure, was 

used for the experiments. Pressurized air in introduced into the bottom of the chamber at 

a pre-selected experimental level, using a tube that exits above the liquid level in the 

containers. At the top of the container, two rupture discs are used to create an 

intermediate chamber between the discs. This chamber is also pressurized and a solenoid 

valve is opened letting the intermediate chamber depressurize. The pressure difference 

across the lower disc becomes too great and disc ruptures causing the upper disc to 

rupture microseconds later. During depressurization, liquid is ejected, samplers 

immediately turned on and aerosol laden air is pulled onto filters. The release is made 

into a cylindrical enclosure, approximately 3 meters high and 2.9 m in diameter with 20 

m

3

volume, about the size of a small room. The enclosure has four high volume samplers 

at 1 m and 1 level and one high volume cascade impactor at the 1.5 m level, equipped 

with appropriate glass fiber filters, as they were use to sample aerosol. The experimental 

device had also been designed for powder release experiments.

The force acting on the liquid was rapid depressurization leading to vaporization and 

entrainment of the solution. The mass airborne was calculated as the difference between 

the source mass and the mass remaining in the apparatus. The mass airborne increased as 

a function of pressure for the uranine solutions and UNH, but the source volume did not 

appear significant in determining the magnitude of the release. Releases were also lower 
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than anticipated. Particle size distributions were measured by cascade impactor samples. 

Significant evaporation of droplets captured in the impactor could mean that the 

measured size distribution does not correspond to that of the actual airborne aerosol. 

Releases of uranine solutions generated the finest, most uniform particles. Median 

diameters were 4 μm and less, with standard deviation (σg) values of 1.6 to 4. These 

particles were predominantly (70-90%), in the respirable size range of 10 μm or less. The 

UNH releases produced larger particle sizes and more polydispersed aerosols. Diameters 

ranged from 3 to 45 μm with σg values from 2.5 to 7.5. Fewer particles of diameter 10 

μm or less were generated, forming 34 to 76% of the aerosol.

For pressures less than 50 psig (0.345 MPag), the aerosol release fraction ARF varies 

from 3E-6 to 5E-5.8 Between 51 psig (0.352 MPag) and 500 psig (3.45 MPag), the ARF 

vary from a bounding value of 2E-3 for lower density liquids such as uranine to 1E-3 for 

high density liquids (such as UNH).9 Table A-6 and A-7 in Volume 2 of DOE 

Handbook show the median droplet size values with their standard deviation for the 

experimental runs. The tables also show the percentage aerosols that were of respirable 

size (< 10 μm). A consultant for Syngenta used the data in the tables with statistical 

analysis to figure out the fraction of droplets that were less than 4 μm diameter for the 

uranine solution. This statistical analysis involved using the median aerosol diameter and 

standard deviation to calculate the aerosol diameter at one standard deviation below andd 

above the median diameter and creating a graph with those three points on log-log paper 

showing aerosol diameter versus cumulative mass fraction. Using the same statistical 

analysis, one can determine the cumulative mass fraction of aerosols that are below 100 

μm. The table below summarizes data for the aerosol releases from only the higher 

pressures of 250 and 500 psig, because these pressures produced significantly higher 

ARF than that for 50 psig. 

Data for Aerosol Releases from High Pressure Venting Above Liquid Level (250-500 

psig only)

Solution Maximum 

mass fraction 

airborne 

Median 

aerosol 

diameter, μm

Mass 

fraction

≤ 4 μm

Mass fraction 

of ARF that is 

≤ 10 μm

Mass fraction 

of ARF that is

≤ 100 μm

uranine 0.002 ~ 4 0.47 - 0.64 0.7 - 0.98 1.0

UNH 0.001 11 - 45 0.24 - 0.46 0.68 - 0.99

D. Superheated Liquid Bounding ARF 0.1 for Temperature ≥50 oC and ≤ 100 oC 

 Bounding ARF 0.01 for Temperature ≤50 oC 

Liquids heated above the boiling temperature of the liquid/solvent/diluent “flash” upon 

 

8

 1994 DOE. V.I, pg 3-22

9

 1994 DOE. V.I, pg 3-3 and 3-22
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release; that is, the excess heat above the boiling point of the liquid is expended in the 

bulk vaporization of the liquid and the remaining liquid is fragmented into fine droplets. 

Experiments were performed to measure the airborne release and size distribution of 

aqueous uranine solution (concentration 10 μg/L) over a limited range of conditions 

(Ballinger, Sutter and Hodgson, May 1987.) Aqueous solutions were heated to pressures 

of 57 psig at ~134 o C, 124 psig at ~161 oC, and 240 psig at 202 oC using source volumes 

of 700 cm3, 350 cm3and 100 cm3. The container was heated using a heat tape on the 

outside. The liquid was released from the open top of the ~4 inch diameter apparatus via 

a double rupture disk arrangement. The aerosols were contained in a stainless steel vessel 

approximately 3 m high and 2.9 m in diameter with a 20 m3volume. Once the chamber 

was depressurized and the liquid ejected, high-volume samplers with glass fiber filters 

were used for mass sampling; a cascade impactor was used for size distribution samples. 

The fraction airborne increased with initial pressure and decreasing source size. In the 

experiments, some of the solution impacted on the ceiling and spread to the walls. Only 

one run (57 psig) has uranine left in the container after release. The residual heat in the 

device following the release my have evaporated the remaining uranine solution from 

most of the runs; however, visual observation of the interior of the chamber following 

sampling did not show a large amount of residue, which would be expected if the 

significant evaporation took place. 

The ARF and RF depend upon the amount of heat available and the heat needed to 

vaporize the solvent. For relatively low energy liquids with temperatures greater than the 

boiling point but less than 50 oC superheat, DOE assumes bounding ARF and RF values 

to be 1E-2 and 0.6 based on the 57 psig run.10 DOE used bounding values of ARF and 

RF of 1E-1 and 0.7 11based on data from the 124 psig and 240 psig runs for scenarios 

where superheated solutions are between 50 oC and 100 oC of superheat. Median 

diameter and standard deviation from each experimental run presented in Table A.9 of 

Vol. II of DOE Handbook were used to statistically graph aerosol diameter versus 

cumulative mass fraction. From these graphs, data on mass fraction of aerosols and 

aerosol sizes are summarized in the table below.

Data for Aerosol Releases from Superheated liquid (Uranine solution) 

Superheat Maximum 

mass fraction 

airborne 

Median 

aerosol 

diameter, μm

Mass 

fraction

≤ 4 μm

Mass fraction 

≤ 10 μm

Mass 

fraction 

≤ 100 μm

≤50 oC 0.01 8.4 0.32 0.62 0.93

≥50 oC and 

≤ 100 oC

0.1 5.9 - 7.7 0.25 - 0.34 0.66 - 0.78 1.0

12

 

10 1994 DOE. V.I, pg 3-4 and 3-29

11

 1994 DOE. V.I, pg 3-4

12

 1994 DOE. V.II, Table A.9, pg A-9
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E. Burning organic fire burning to complete dryness or burning solvent over 

aqueous phase burning to complete dryness. Bounding ARF 1E-1 (0.1)

Scenarios E and F address potential releases of solid contaminant due to thermal stress 

for organic solutions or organic and aqueous solutions present together. An organic 

burning liquid layer over an aqueous solution produces turbulence. During burning and 

subsequent evaporation, drops of liquid become entrained and suspended into the air. 

Experiments were conducted using various solutions of TBP (Tri-normal Butyl 

Phosphate) in kerosine with an aqueous solution of an acid (Halverson, Ballinger and 

Dennis1987). Either or both solutions contained radionuclides. Small volumes of liquids 

were place in metal beakers and the liquids heated by heating tapes wrapped around the 

metal beaker. The organic liquid ignited and air was drawn up the chimney. Airborne 

particles were collected on glass filters as a function of time. 

Based on several experiments, the conservative upper bound ARF was 1E-1 (rounded up 

from 7E-2 for highest value in Table 3-13).

13

 The RF was assumed to be 1.0 in absence 

of measured value. In absence of additional information, we will assume that probably 

100% of the particles were less than 100 μm in diameter. The RF was measured for only 

one experiment with a value of 0.99 

F. Aqueous solution or air died salt under gasoline fire on heat conducting 

surface (i.e. metal). Bounding ARF 2E-1

Experiments were conducted in a wind tunnel using UNH (uranyl nitrate hexahydrate) 

and air-dried UNH on various substrates (soil, vegetation on soil, asphalt and stainless 

steel) during a shallow pool gasoline fire (Mishima and Schwendiman 1973). Liquid 

UHH was placed in a 22-inch diameter flange in the floor of the wind tunnel. One gallon 

of gasoline was poured over the surface, ignited and the air drawn over the burning 

surface. Airborne particles were then sampled. The highest ARF measured was 1.14E-1 

for the stainless steel substrate at a windspeed of 10 m/s (22 mph). The RF for the 

stainless steel substrate experiment was 0.34 but was as high as 0.75 for other 

experiments in this scenario including the other substrates.14 DOE represented the 

bounding ARF as 2E-1 for this scenario with an RF of 0.3 when summarizing the data on 

page 3-6 of Volume I of their handbook, although the highest experimental value 

reported was 1.14E-1. DOE notes that if a substrate conducts heat well, the liquid can be 

boiled rapidly generating conditions much more favorable to generation of airborne 

 

13 1994 DOE. V.I, pg 3-6 and 3-45.

14

 1994 DOE. V.I, pg 3-48.
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liquid droplets. To be conservative for the extremely limited data set, DOE probably 

rounded up the ARF to 2E-1. For EPA’s purposes, we will assume that probably 100% 

of the particles had diameters less than 100 microns.

G. Aerodynamic Entrainment and Re-suspension Bounding ARR 9E-5 

(0.00009)/hr

Liquid re-suspension. For those large aerosol droplets that fall out on the facility site 

without reaching the community, the possibility exists that this material could become 

entrained back into the air by contact with wind upon the surface where it was deposited. 

The DOE Handbook provides resuspension rates know as airborne release rates (ARR) 

for resuspension of liquids from soil with unit of measure of hours -1. The ARR 

represents the fraction of deposited material resuspened over time and are in the form of 

droplets aerodynamically entrained from various surfaces under different conditions. 

For example, aerodynamic entrainment (resuspension) at higher air velocities of UNH 

solution from various surfaces was measured in wind tunnel experiements (Mishima and 

Schwendiman, August 1973). From this data, a bounding ARR of 9.0E-5 with an RF of 

1.0 is conservatively assumed. 15 

DOE notes that there appear to be very large differences in suspension rates under 

experimental test conditions as well as an order of magnitude uncertainty in 

measurements for individual conditions and on this basis, have applied conservative 

values. Short time frames of less than 100 hours should be used with these values 

because they are intended for immediate post- accident conditions and freshly deposited 

material.16 If one assumed that cleanup did not occur for about 4 days (100 hours), the 

fraction of the deposited release that would become airborne would be 9E-3 (9E-5/hr 

times 100). We can round this up to 1E-2.

1. Powder re-suspension

However, large droplets that fall out on the facility site could dry out into smaller 

particles and then become re-suspended. The DOE Handbook, based on review of 

literature data, found that a bounding re-suspension rate of 4E-5/hr determined by Sehmel 

and Lloyd (1976) was reasonable bounding ARR value for resuspension of powders 

deposited on various outdoor substrates.17 The ambient conditions would be normal 

process facility ventilation flow or less, or nominal atmospheric wind speeds (<2 m/s (4.5 

mph) with gusts up to 20 m/s (44 mph)). The test conditions for the bounding resuspension rate of 4E-5/hr were based upon an aqueous slurry of submicron sized 

calcium molybdate stabilized with surfactant that was sprayed on the surface of a lightly 

vegetated area. Material re-suspended was collected by samplers and analyzed.

If one assumes that cleanup did not occur for about 4 days (100 hours), the fraction of the 

 

15

 1994 DOE V.I, pg. 3-5 and 3-41

16

 1994 DOE. V.I, pg 3-5

17

 1994 DOE. V.I, pg. 4-96 and pages 4-100-101 
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deposited release that could become airborne by resuspension would be 4E-3 (ARR of 

4E-5/hr times 100 hrs). 

The DOE Handbook also reported a bounding re-suspension rate of 1E-2/passage based 

on passage of vehicles through solid particles of ZnS <25 mm in diameter deposited on 

an asphalt road (Sehmel 1973). The re-suspension value decreases rapidly over time and 

are about an order of magnitude after four days of aging.18 

2. Data from Center for Chemical Process Safety (CCPS) Vapor Cloud Modeling 

Subcommittee’s “Aerosol Project”. 

For this work, the term “aerosol” means any liquid not falling to the ground within a 

short distance of the point of release. Field tests were conducted in 1989 for releases of 

superheated water from a storage tank through a release orifice, (Woodard 1995; 

Woodard and Johnson 1999). Water releases involved storage temperatures from 105 -

215 oC (378 to 488 K) corresponding to pressures at release orifice of 26.7 to 310 psia. 

The storage tank was pressurized with nitrogen pad to insure that fluid state at the release 

orifice was 100% liquid. The orifice was located 4 foot (1.33 m) above a 50 foot (15.2 

m) capture system designed to collect any liquid falling to the ground and direct the 

liquid to collection and weighing vessels. Capture pans were 50 foot long and 20 foot 

wide in five 10 foot long segments. The entire storage tank and capture system was 

enclosed in a greenhouse to shield the equipment from effects of the wind. 

Tests were also made for chlorine, CFC-11, methylamine, and cyclohexane (1991). 

Chlorine and CFC-11 are gases. Methylamine is a highly volatile chemical (vapor 

pressure = 300 mm Hg) and cyclohexane is less volatile (vapor pressure = 95 mm Hg) 

compared to water (vapor pressure = 24 mm Hg). Results for water and cyclohexane are 

summarized below and are based on 20 data runs for each liquid.

19

 The fraction airborne 

was calculated from the reported fraction captured. (100 - % captured)/100 = fraction 

airborne.

Liquid Mass 

fraction 

airborne 

Aerosol 

diameter, 

μm

Water 0.03 - 0.54 54 - 440

Cyclohexane 0.36 - 0.94 148 - 630

References

 

18 1994 DOE. V.I, pg. 4-102

19

 1995. Woodward. Pgs 130-131, 137
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DOE Handbook, Airborne Release Fractions/Rates and Respirable Fractions for 

Nonreactor Nuclear Facilities. December 1994. US Department of Energy, Washington, 

DC 20585 DOE-HDBK-3010-94. Volume 1- Analysis of Experimental Data and 

Volume II- Appendices. 

Ballinger, M.Y., S.L. Sutter and W.H. Hodgson. May 1987. New Data for Aerosols 

Generated by Releases of Pressurized Powders and Solutions in Static Air, NUREG/CR4779 (PNL)-6065), Pacific Northwest Laboratory, Richland, WA 99352. 

Borkowski, R., H. Bunz and W. Schoeck. May 1986. Resuspension of Fission Products 

During Severe Accidents in Light-Water Reactor, KfK 3987 (EUR 10391 EN), 

Kernforschungszentrum Karlsruhe, Germany.

Garner, F.H., S.R.M. Ellis and J.A. Lacey. 1954. “The Size Distribution and Entrainment 

of Drops”, Trans. Inst. Chem. Eng., 32 : p 222

Halverson, M.A., M.Y. Ballinger and G.W. Dennis. March 1987. Combustion Aerosols 

Formed During Burning of Radioactively Contaminated Materials – Experimental 

Results. NUREG/CR-4736 (PNL-5999), Pacific Northwest Laboratory, Richland, WA. 

Heger, R., et al. 1982. “Bestimmung der Quell terme bei verfahrenstechnischen 

Opertationen im Weideraufbeitungsprozess”, KfK Nachrichten, 14 (3):p 143.

Heger, R. and Th. Waescher. 1983. “Charakteriserung der Aerosolemissionen im 

Bahaelterabgas einer Wiederaufarbeitungsanlage” Jahrestagung Jerntecknik, Berlin, 

Tagungsband, p 423.

Mishima, J. and L.C. Schwendiman. August 1973. Some Experimental Measurements 

of Airborne Uranium (Representing Plutonium) in Transportation Accidents, BNWL1732, Pacific Northwest Laboratory, Richland, WA 99352.

Mishima, J., L.C. Schwendiman and J.E. Ayer. October 1978. Increment of Analysis -

An Estimate of Airborne Release of Plutonium from Babcock and Wilcox Plant as a 

Result of Severe Wind hazard and Earthquake, PNL-2812, Pacific Northwest Laboratory, 

Richland, WA 99352.

Mishima, J., L.C. Schwendiman and C.A. Radasch. November 1968. Plutonium Release 

Studies IV. Fractional Release From Heating Plutonium Nitrate Solutions in Flowing Air 

Stream, BNWL-931, Pacific Northwest Laboratory, Richland, WA 99352.

Sehmel, G.A. 1973. “Particle Resuspension from an Asphalt Road Caused by Car and 

Truck Traffic”, Atmospheric Environment. 7: pp 291-301.

Sehmel, G.A. and F.D Lloyd. 1976. “Resuspension Rates From A Circular Field 

Source”, Annual Report 1975 to the USERDA Division of Biomedical and 

Environmental Research Part 3. Atmospheric Sciences, BNWL-2000, Part 3, Pacific 
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Northwest Laboratory, Richland, WA.

Sehmel, G.A. and F.D. Lloyd. 1976. “Particle Resuspension Rates”, AtmopshereSurface Exchange of Particulate and Gaseous Pollutants (R.D. Englemann and G.A. 

Sehmel, Ed), ERDA Symp. Series #38, Technical Information Center – Energy Research 

and Development Center (Now U.S. Department of Energy), Washington, DC

Sutter, S.L. August 1983. Aerosols Generated by Release of Pressurized Powders and 

Solutions in Static Air, NUREG/CR-3903 (PNL-4566), Pacific Northwest Laboratory, 

Richland, WA 99352.

Woodward, J.L. 1995. Aerosol Drop Size Correlation and Corrected Rainout Data 

Using Models of Drop Evaporation, Pool Absorption and Pool Evaporation. In: 

International Conference and Workshop on Modeling and Mitigation the Consequences 

of Accidental Releases of Hazardous Materials, September 1995. New York: American 

Institute for Chemical Engineers Center for Chemical Process Safety , pp. 117-147.

Johnson, D.W. and Woodward, J.L. 1999. Release- A Model with Data to Predict 

Aerosol Rainout in Accidental Release. 1999. Center for Chemical Process Safety of the 

American Institute of Chemical Engineers.