A Preliminary Analysis of the Nerve Agent Attack of August 21, 2013 Against
Unprotected Civilians in the Suburbs of Damascus, Syria
17.477 The Politics and Technology of Weapons of Weapons Systems
Massachusetts Institute of Technology Theodore A. Postol
Professor of Science, Technology, and National Security Policy 1
The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Political Reasons Why Assailants in Syrian Civil War Might Want to Execute Chemical Attacks
Political Reasons Why Assad Government Might Want to Execute Chemical Attacks
Terrifying Causes people to leave
Does not require massive artillery attacks or ground operations to clear an area
Political Reasons Why Rebel Groups Might Want to Execute Chemical Attacks
Increases the likelihood of international intervention on behalf of the rebels Reduces the strength of rebel factions that could complete for power after
the collapse of the Assad regime Settles old scores between ethnically different groups
2The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
A Man and Baby in Iraq in 1988. Investigators Found Evidence of a Nerve Agent in Soil in 1992
3The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Dead Pigeons Photographed After the Nerve Agent Attack in Damascus Suburb on August 21, 2013
4The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
The Attack Was Much Larger than Has Been Reported in the Press
1. Analysis of the Munitions Debris Left from the Attack Suggests that the Attack Was Roughly Ten Times Larger in Terms of the Weight of Delivered Sarin Than Has So Far Been Reported by the Press.
2. This Error Appears to be Due to a Misidentification of How the Munitions Worked
3. It Appears that Each Launched Munition Contained About 100 lbs of Sarin (50 Liters) Rather than the 10 lbs (5 Liters) Widely Reported by the Press
5The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
How Explosives Can Be Used to Dispense a Chemical Agent
6The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Explosive Dispersion of Sarin Liquid (Below is Water) Creates Small Droplets That Quickly Evaporate in Air of Fall to the Ground Creating a
Thin Layer of Liquid that Then Quicly Evaporates
3m
10,000 f/s
7The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Efficiency of Dispersion
Depends on: 1. Ratio of the Weight of Explosives to Dispersant 2. Temperature of Explosive Gasses 3. Geometrical Method of Dispersion 4. Fragility of Dispersant Molecules to Heat and Shock 5. Thickness of Casing or Strength of Enclosing Plug
8The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Efficiency of Dispersion Mechanisms Can Vary Strongly with Method
9The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
The Munition Used for Dispersing the Chemical Agent in the Attacks in Damascus on August 21 Delivered
a Far Larger Dose of Sarin than Reported by the Press
10The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Estimated Dimensions and Payloads of Munitions Used in Sarin Gas Attack on Suburb of Damascus (August 21, 2013)
Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
31 cm
125 cm
12.5 cm
Canister VolumeMisreported by Press
5.7 to 6.7 Liters
Rocket MotorExit Nozzle
StabilizingRing
RocketMotor
Rocket MotorFins
CanisterFront Wall
Canister forHolding Chemicals(About 50 Liters,
10 Times Larger ThanReported in the Press)
65 cm
35 cm
Contact orAcceleration Fuse
Explosive forDispensing Chemicals
11 cm
BlastContainment
Plate
11The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Mechanism for Tearing Open Payload Container Used in Sarin Gas Attack on Suburb of Damascus (August 21, 2013)
Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
31 cm
125 cm
12.5 cm
Canister VolumeMisreported by Press
5.7 to 6.7 Liters
Rocket MotorExit Nozzle
StabilizingRing
RocketMotor
Rocket MotorFins
CanisterFront Wall
Canister forHolding Chemicals(About 50 Liters,
10 Times Larger ThanReported in the Press)
35 cm
Contact orAcceleration Fuse
Explosive forDispensing Chemicals
11 cm
BlastContainment
Plate
Explosion Partially Contained by Blast Plate Tears the Front End of
the Chemical Canister Open Materials Are Then Thrown Upward into the Air Around the Impact Point
12The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Canister Assembly of Munition Used in Sarin Gas Attack on Suburb of Damascus (August 21, 2013)
Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
Front Plate of Canister Section
Filling or Venting Stations for Chemicals and Explosive Gases?
Adapter for Connection to Rocket Motor
Second Welded Plate –Possibly Designed to Take Pressure from Expanding Explosive Gasses
13The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Front End of Canister Assembly of Munition Used in Sarin Gas Attack on Suburb of Damascus (August 21, 2013)
Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
Front Plate of Inner Canister Section Where Explosive
is Contained
Adapter for Connection to Rocket Motor
Note That the Front of the Canister is Bent and Aligned
with the Direction of the Camera
Edge of Metal Attached to
Front Flange
14The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Rear Flange of Chemical Container
Chemical Filling Holes
Front Flange of Chemical Container
Hole for Explosive Detonator Associated
with the Fuse
15The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Estimated Dimensions and Payloads of Munitions Used in Sarin Gas Attack on Suburb of Damascus (August 21, 2013)
Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
31 cm
5700 to 6000 cubic cm
125 cm
11 cm
Rocket MotorExit Nozzle
StabilizingRing
Rocket MotorFins
RocketMotor
Internal CanisterIdentified by Press
CanisterFront Wall
60 cm
12.5 cm
Canister Volume About
Chemical Canister SectionAdaptor Plate for
(Possible Holes for Filling and/or Dispensing Cemicals)
f H ldi Ch i l
16The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Type of Chemical Munitions Canister Likely Used in Sarin Gas Attack on Suburb of Damascus (August 21, 2013)
Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
17The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Munition Used in Sarin Gas Attack on Suburb of Damascus (August 21, 2013)
Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
RocketMotor
Chemical CanisterBroken Off
Tail Section
Reinforcing Tail-Fin Ring 18
The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Munition Used in Sarin Gas Attack on Suburb of Damascus (August 21, 2013)
Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
Expended and Impact-Damaged
Rocket Motor
Partially Bent and Crushed Explosive
Canister
Tail SectionReinforcing Tail-Fin Ring
Rocket Motor Nozzle
Adapter Section for Connecting Rocket Motor and Canister and for
Filling and/or Dispensing Chemicals
19The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Rocket Nozzle and Rear Fin Assembly of Munition Used in Sarin Gas Attack on Suburb of Damascus (August 21, 2013)
Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
Rocket Motor Nozzle
20The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Back End of Canister Assembly of Munition Used in Sarin Gas Attack on Suburb of Damascus (August 21, 2013)
Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
Attachment RingFor Rocket Motor
21The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Location of Main Gas Attack on Suburb of Damascus (August 21, 2013)
22The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
����
��
23The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
�
��
�
Blown Off Skin of 50 Liter Chemical
Container
Carcass of Explosive Gas
Dispenser Rocket Motor
Casing
24The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Blown Off Skin of 50 Liter Chemical
Container
Carcass of Explosive Gas
Dispenser
Rocket Motor Casing
25The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Carcass of Explosive Gas
Dispenser
Blown Off Skin of 50 Liter Chemical
Container
Rocket Motor Casing
26The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Toxicity of Sarin
27The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Sarin – Organophosphate Molecule
[(CH3)2CHO] CH3P(O)F
28The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Sarin – Organophosphate Molecule
[(CH3)2CHO]
(CH3)
POF
29The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Sarin – Organophosphate Molecule
[(CH3)2CHO]
(CH3)
POF
The POF piece of the Sarin molecule is extremely stable, and tends to persist (potentially for years) in the environment.
30The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Characteristics of Nerve Agents Nerve agents –
examples are Sarin (GB), Tabun (GA), Soman (GD), and VX. These agents work by interfering with cholinesterase, the enzyme that breaks down acetylcholine after its release by the nervous system. Symptoms of nerve-agent poisoning include difficulty in breathing, sweating, nausea, vomiting, staggering, coma, and convulsion, followed by cessation of breathing and death. When inhaled, nerve agents are lethal in concentrations ten times smaller than choking, blood, or blister agents; like mustard, they are readily absorbed through the skin. They vary in consistency from sarin, which is watery and volatile, to VX, which has the viscosity and volatility of motor oil. Nerve agents were first discovered by the Germans shortly before World War II. Production costs are low--as little as $10 to $20 per kilogram of agent.
31The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Nerve Agents Inhibit the Destruction of Acetylcholine (Ach), Leaving the Sodium (Na) Gates Open
Nerve Agents Interfere with Cholinesterase. Cholinesterase is an Enzyme that Breaks Down Acetylcholine After it is Release by the Nervous System.
Sodium(Na) Gate
Sodium (Na) Gate Receptors Open when ACh binds with the receptors. The firing is achieved by from Sodium passing through the gate during the ACh binding process. If ACh is not broken down by Cholinesterase, it remains present in the synapse, and the Sodium Gates continue to fire.
32The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Symptoms of Sarin Poisoning (In Order of Appearance)
1. Runny nose 2. Bronchial secretions 3. Tightness in the chest 4. Dimming of vision 5. Pin-Point Pupils 6. Drooling 7. Excessive perspiration 8. Nausea, Vomiting 9. Involuntary defecation, urination 10. Muscle tremors, convulsions 11. Coma 12. Death by Asphyxiation
33
The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Symptoms of Sarin Poisoning (As They Appear in Victims)
Pinpoint Pupils Excessive Sweating and Trouble Breathing
Foaming at Mouth and Nostrals – Death by Sophocation 34The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Symptoms of Sarin Poisoning (As They Appear in Victims)
35The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Why Choose Sarin Over VX for a Gas Attack Against a Civilian Population?
1. Sarin Has the Density of Water.
2. Sarin Evaporates at the Same Rate as Does Water (Hours or Less).
3. Sarin Has Nearly the Same Viscosity as Water.
4. Sarin Thus Creates a Lethal Gas-Inhalation Threat Very Fast, Before Populations Can Recognize Its Presence and React.
5. VX Does Not Evaporate Quickly (Takes Many Days).
6. VX Has a Viscosity Similar to that of Motor Oil.
7. VX Will “Persist” Long After and Attack, Making Verification of Chemical Attack Much Easier.
36The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Properties of Various Chemical Warfare Agents.
Respiratoryb Percutaneousc
Agent
Volatility (mg/m3)a
Lethal Dose LCt50
(mg·min/m3)
Incap. Dose ICt50
(mg·min/m3)
Lethal Dose LCt50
(mg·min/m3)
Tabun (GA) 610 400 300 40,000
Sarin (GB) 22,000 100 75 15,000
Soman (GD) 3,900 100 75 10,000d
VX 10 100 50 1,000d
Mustard (HD) 920 1500 200 10,000
Phosgene (CG) 4,000,000 3200 1600 n.a.
Hydrogen Cyanide 1,100,000 5000e 2000e n.a. a Mass of vapor per cubic meter of air at 25° C. For comparison, the volatility of water at 25° C is 23,000 mg/m3. b Median lethal and incapacitating dosage for unprotected men breathing at a rate of 10 liters/min. c Median lethal dosage for men in ordinary combat clothing. d SIPRI, CB Weapons Today, pp. 42-43. e Depends on concentration; values given here are for a concentration of 100 mg/m3 LCt50 = 2000 mg-min/m3 at a concentration of 200 mg/m3. Source: Military Chemistry and Chemical Compounds (Washington, DC: Department of the Army, FM 3-9, October 1975). 37The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Illustration for Classroom of the Toxicity Level of Sarin Nerve Agent.
38The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Illustration for Classroom of the Toxicity Level of Sarin Nerve Agent.
Assume release in this room – Room Dimensions Room Volume ~ 3m high � 4m wide � 8m wide = 96 m3 1 gram of Nerve Agent Released in Room Volatility leads to density of 0.01 gram/m3 (10 mg/m3) Hence, Roughly ten to Twenty minutes of breathing while in the room will lead to death.
39The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Illustration for Classroom of the Toxicity Level of Sarin Nerve Agent.
One cm3 of Sarin ~ One Gram ~ 1000 milligrams.
40The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Current Information About Areas that Were Hit
41The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Ethnic and Political Map of Areas of Damascus Attacked with Sarin Attack of August 21, 2013
42The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Location of Main Gas Attack on Suburb of Damascus (August 21, 2013)
Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
Presidential Palace
Area Hit with Munitions
1 Mile
43The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Size of Damascus Gas-Attack Area Projected onto the City of Boston, MA (August 21, 2013)
Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
Area Hit with Munitions
1 Mile
44The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Size of Damascus Gas-Attack Area Projected onto the City of Washington, DC (August 21, 2013)
Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
Area Hit with Munitions
1 Mile
45The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Area of Main Gas Attack on Suburb of Damascus (August 21, 2013) Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
1 Mile
46The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Buildings in Area of Main Gas Attack in Damascus (August 21, 2013) Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
100 Yards
47The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Buildings in Area of Main Gas Attack in Damascus (August 21, 2013) Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
100 Feet
48The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Buildings in Area of Main Gas Attack in Damascus (August 21, 2013) Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
Building in Area Attacked with Sarin
49The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Estimate of Possible Population Densities in Built Up Areas Where Munitions May Have Fallen (August 21, 2013) Attack Takes Place at About 2:30 AM, Atmospheric Conditions Strongly Stable
Assumptions for Guestimate: Building ~ 100ft × 100ft = 10,000 ft2 ? Roughly 10 Apartments of 1000 ft2 each per floor? 4 Occupants per Apartment = 40 Occupants per floor? 4 to 5 Stories = 160 – 200 Occupants? One Munition ~ 50 kg (100 lbs) Sarin (About 50 Quarts) Cloud ~ 10 m × 10 m× 10 m = 1000 m3, 50 kg = 50 × 106 milligrams Density in Initial Cloud ~ 50,000 mg/m3 30 minute Cloud Grows to About 100 m on a Side and 20 meters in the vertical direction Volume of Cloud ~ 100 m × 100 m× 20 m = 1,000,000 m3 5 × 107 / 1× 106 ~ 50 mg/m3 Lethal Dose ~ 100 mg × m3 / min
50The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Effects of Weather, Air-Motion, Particle Size,
and Other Factors on the Effectiveness of Chemical and Biological Agents
51The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Factors Affecting Aerosol and Solid-Particle Deposition Regions
ys
Cloud of Solid-Particles or Liquid-Droplets
z
y
x
52The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Small Scale Air Motion Carries the Gas and Small Droplets
Air Can Vertically Rise Due to Hot Surfaces that are Illuminated by the Sun Air Can Also Settle if there is Efficient Radiation Cooling at Night
�
53The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Unstable Meteorological Conditions
Bright and Sunny Days
54The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Particle and Gas Dispersal Paths in Unstable Meteorological Conditions
Bright and Sunny Days
55The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Formation of Mixed Layer Near the Ground
Cool Dry Nights with Little or No Wind and Cloud Cover
56The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Factors Affecting Aerosol and Solid-Particle Deposition Regions
ys
Cloud of Solid-Particles or Liquid-Droplets
z
y
x
57The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Estimating Inhalation Doses from Chemical/Biological Attacks
� � � �MaterialMassDose=Concentration Time TimeVolume
Q x Q xt
xx y z y zt
��� � � � ��
� � �� � � �
g g
3mg minDose=Concentration Time
m�
gg
For example:
3mg5 minutes in 20 leads to 50% Fatalitiesm
3mg10 minutes in 10 leads to 50% Fatalitiesm
3mg20 minutes in 5 leads to 50% Fatalitiesm
×
× ×
58The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
The Gaussian Plume Model for Predicting Aerosol Dispersion
� � � �2 2
2 22 2, y z
y h
y z
Q xC x y e e
U
�
� �
�
Where C(x,y) is the time-integrated ground-level concentration of agent in mg s/m3 Q(x) is the weight of material released (mg) �y and �z are the cross-wind and vertical standard deviations of the concentration distribution at the downwind distance x from the release point. U is the effective wind speed (m/s) h is the height of the cloud-center (m)
59The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
The GaussianPlume Model for Predicting Aerosol Dispersion
� �1 y
y y yf I x x�
�� �
� �1 zz z zf I x x � �� �
Where I, �, and � are constants that vary with the atmospheric stability and surface roughness f depends on the length of time of the release f � 1 for evaporation of a puddle and f � 0.3 for explosively generated aerosol clouds
60
The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
The Gaussian Plume Model for Predicting Aerosol Dispersion
Parameters of Gaussian plume Aerosol Dispersal Model for
Unstable, Neutral, and Stable Meteorological Conditions
Atmospheric Stability Condition
Rural Iy �y �y Iz �z �z
Unstable 0.30 0.0001 -0.5 0.20 0.00 0 Neutral 0.15 0.0001 -0.5 0.10 0.0015 -0.5 Stable 0.10 0.0001 -0.5 0.05 0.0003 -1
Atmospheric Stability Condition
Urban Iy �y �y Iz �z �z
Unstable 0.33 0.0004 -0.5 0.22 0.001 0.5 Neutral 0.19 0.0004 -0.5 0.13 0.0003 -0.5 Stable 0.14 0.0004 -0.5 0.07 0.0015 -0.5
61The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Factors Affecting Aerosol and Solid-Particle Deposition Regions Source: 1000 m3 (10×10×10 m); 100 kilograms, 100% Ingestion Efficiency
0 1000 2000 3000 4000 5000 60000
50
100
150
200
250
300
350
400
450
500Unstable Rural Cloud Dispersal Dimensions
Cloud Downwind Range (m)
Cros
s Wind
Widt
h an
d Ve
rtica
l Heig
ht (m
)
0 1000 2000 3000 4000 5000 60000
100
200
300
400
500
600
700
800
900
1000Dispersal in Unstable Rural Conditions
Cloud Downwind Range (m)
Tota
l Dos
e as
Clou
d Pa
sses
Vict
im (m
g)
0 1000 2000 3000 4000 5000 60000
50
100
150
200
250
300
350
400
450
500Neutral Rural Cloud Dispersal Dimensions
Cloud Downwind Range (m)
Cros
s Wind
Widt
h an
d Ve
rtica
l Heig
ht (m
)
0 1000 2000 3000 4000 5000 60000
100
200
300
400
500
600
700
800
900
1000Dispersal in Neutral Rural Conditions
Cloud Downwind Range (m)
Tota
l Dos
e as
Clou
d Pa
sses
Vict
im (m
g)
0 1000 2000 3000 4000 5000 60000
50
100
150
200
250
300
350
400
450
500Stable Rural Cloud Dispersal Dimensions
Cloud Downwind Range (m)
Cros
s Wind
Widt
h an
d Ve
rtica
l Heig
ht (m
)
0 1000 2000 3000 4000 5000 60000
100
200
300
400
500
600
700
800
900
1000Dispersal in Stable Rural Conditions
Cloud Downwind Range (m)
Tota
l Dos
e as
Clou
d Pa
sses
Vict
im (m
g)
0 1000 2000 3000 4000 5000 60000
50
100
150
200
250
300
350
400
450
500Unstable Urban Cloud Dispersal Dimensions
Cloud Downwind Range (m)
Cros
s Wind
Widt
h an
d Ve
rtica
l Heig
ht (m
)
0 1000 2000 3000 4000 5000 60000
100
200
300
400
500
600
700
800
900
1000Dispersal in Unstable Urban Conditions
Cloud Downwind Range (m)
Tota
l Dos
e as
Clou
d Pa
sses
Vict
im (m
g)
0 1000 2000 3000 4000 5000 60000
50
100
150
200
250
300
350
400
450
500Neutral Urban Cloud Dispersal Dimensions
Cloud Downwind Range (m)
Cros
s Wind
Widt
h an
d Ve
rtica
l Heig
ht (m
)
0 1000 2000 3000 4000 5000 60000
100
200
300
400
500
600
700
800
900
1000Dispersal in Neutral Urban Conditions
Cloud Downwind Range (m)
Tota
l Dos
e as
Clou
d Pa
sses
Vict
im (m
g)
0 1000 2000 3000 4000 5000 60000
50
100
150
200
250
300
350
400
450
500Stable Urban Cloud Dispersal Dimensions
Cloud Downwind Range (m)
Cros
s Wind
Widt
h an
d Ve
rtica
l Heig
ht (m
)
0 1000 2000 3000 4000 5000 60000
100
200
300
400
500
600
700
800
900
1000Dispersal in Stable Urban Conditions
Cloud Downwind Range (m)
Tota
l Dos
e as
Clou
d Pa
sses
Vict
im (m
g)
U=1 m/s U=1 m/s U=5 m/s U=5 m/s
U=2 m/s U=2 m/s U=1 m/s U=1 m/s
U=5 m/s U=5 m/s U=2 m/s U=2 m/s
Cross-Range Disperson Distance
Vertical Dispersion Distance
Cross-Range Disperson Distance
Vertical Dispersion Distance
Vertical Dispersion Distance
Cross-Range Disperson Distance
Cross-Range Disperson Distance
Cross-Range Disperson Distance
Vertical Dispersion Distance
Vertical Dispersion Distance
Cross-Range Disperson Distance
62The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Factors Affecting Aerosol and Solid-Particle Deposition Regions Source: 1000 m3 (10×10×10 m); 100 kilograms, 100% Ingestion Efficiency
Bright and Sunny Day Wind Speed About 2 m/s
~100 mg Kills Resting Adult Male,
0 1000 2000 3000 4000 5000 60000
50
100
150
200
250
300
350
400
450
500Unstable Urban Cloud Dispersal Dimensions
Cloud Downwind Range (m)
Cros
s Wind
Widt
h an
d Ve
rtica
l Heig
ht (m
)
0 1000 2000 3000 4000 5000 60000
100
200
300
400
500
600
700
800
900
1000Dispersal in Unstable Urban Conditions
Cloud Downwind Range (m)To
tal D
ose
as C
loud
Pass
es V
ictim
(mg)
Range at Which Munition delivers
a Lethal Dose (400m, 800 seconds or About 12 to 13 minutes)
63The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Factors Affecting Aerosol and Solid-Particle Deposition Regions Source: 1000 m3 (10×10×10 m); 100 kilograms, 100% Ingestion Efficiency
Cool Dry Nights with Little or No Wind and Cloud Cover Wind Speed About 2 m/s
~100 mg Kills Resting Adult Male,
0 1000 2000 3000 4000 5000 60000
50
100
150
200
250
300
350
400
450
500Stable Urban Cloud Dispersal Dimensions
Cloud Downwind Range (m)
Cros
s Wind
Widt
h an
d Ve
rtica
l Heig
ht (m
)
0 1000 2000 3000 4000 5000 60000
100
200
300
400
500
600
700
800
900
1000Dispersal in Stable Urban Conditions
Cloud Downwind Range (m)
Tota
l Dos
e as
Clou
d Pa
sses
Vict
im (m
g)
Range at Which Munition delivers a Lethal Dose
(2300m, 1150 seconds or About 19 to 20 minutes) 64The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Ground-Level Release of Sarin in Stable Dispersal Conditions
(2 m/s Wind Speed)
65The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Ground-Level Release of 1000 Kilograms Sarin in Stable Dispersal Conditions
Ground-Level Release of 1000 Kilograms of Sarin
(2 m/s Wind Speed)
66The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Factors Affecting Aerosol and Solid-Particle Deposition Regions
67The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
1000 Kilograms VX (Defense Intelligence Agency Scud Release)
68The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Ground-Level Release of 1000 Kilograms Sarin in Stable Dispersal Conditions
(2 m/s Wind Speed)
69The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Factors Affecting Aerosol and Solid-Particle Deposition Regions
ys
Cloud of Solid-Particles or Liquid-Droplets
z
y
x
70The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
ams Sarin in Stable Dispersal Conditions
Distance Toxic Cloud Travels in 2.5 Minutes
(2 m/s Wind Speed)
Arrives at 20+ Minutes After Release
71The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Ground-Level Release of 1000 Kilograms Sarin in Stable Dispersal Conditions
72The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Ground-Level Release of 100 Kilograms Sarin in Stable Dispersal Conditions
*Roughly the same as 1000 Kilogram Dispersal with 10% Absorption/Dispensing Efficiency
73The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Ground-Level Release of 1000 Kilograms Sarin in Unstable Dispersal Conditions
74The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Ground-Level Release of 100 Kilograms* Sarin in Unstable Dispersal Conditions
*Roughly the same as 1000 Kilogram Dispersal with 10% Absorption/Dispensing Efficiency
75The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Concluding Remarks (1 of 3) � On August 21, 2013 a vicious and very carefully planned attack was executed on unprotected civilians
various suburbs of Damascus, Syria. � 1400 to 1500 people were killed from exposure to nerve agent. Between 400 and 500 of these people
were children. � This attack was designed to cause the maximum possible harm to civilians with the technology that
was available to the attacker. � The attack was executed at a time of day that would maximize the density of nerve agent near the
ground where the civilians reside. � The pancake geometry of spreading nerve agent at that time of day greatly increased the area on the
ground, causing the maximum number of people possible to be exposed to an organophosphorous nerve agent.
� If soldiers with proper equipment had been attacked in this manner, casualties would have almost certainly been very low.
� Detectors would have warned the soldiers that chemicals were present. � The chemical agent would take tens of minutes or more to reach soldiers that are outside the
immediately affected delivery areas. � Rapid communications would have made it possible for properly equipped soldiers to put on gas
masks. � Thus, the only effective target for this kind of attack are unprotected civilians.
76The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Concluding Remarks (2 of 3) � Very large amounts of high explosive munitions would be required to drive people out of the areas that
were hit. � On the order of thousands of high explosive munitions would be required to effectively kill the
thousands of people living in these areas. � The chemical munitions that achieve the same goal were probably delivered by no more than several
tens of munitions. � The question currently under debate in the United States is whether military action against those who
use such weapons could produce useful results.
77The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
Concluding Remarks (3 of 3) � These results might include: � Deterring these kinds of attacks against civilians. � Weakening a brutal existing regime and moving it closer to collapse. � Send warnings to others who might contemplate such attacks in the future.
� Unexpected results could include: � The mass murder of innocent bystanders associated with the collapse of a terrible regime. � Mass reactions against the United States and its allies for interventions that are seen as aimed at
replacing unfriendly governments with friendly governments. � Reactions from extremist elements who would see Western intervention as further proof of western ill
intentions towards the people of the region. � A provoking of the Syrian regime to “take off the gloves” and use chemicals more widely. � And numerous totally unpredictable results that could influence the politics within and without the
region for decades.
� What would you do if you were in the position to take a military action in response to this atrocity?
78The Nerve Agent Attack of August 21, 2013 in Damascis, Syria
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