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File: 123096_sep96_decls1_0075.txt
Subject: DETECTION OF MEDICAL DEFENSE AGAINST BIOLOGICAL MATERIALS
Unit: OTSG
Parent Organization: HSC
Box ID: BX003203
Folder Title: DETECTION OF MEDICAL DEFENSE AGAINST BIOLOGICAL MATERIALS
Document Number: 1
Folder Seq #: 21
Very I i ne par Li C Its, wi Lh a d tameLe r smal Ier Lhan 0.5 Mi cron, are
a Iimi naled l,y t ur6u I ciice in a I r ducts, as L heir k int:L IC energy is
insufficient for LheM LO seLLie On Lhe respiratory mucosae or aL
alveolar level. Consequently, only particles WILH a diameler
ranging Irum 0.5 Lo 5 microns will penetrate and seLLIe in Lhe
lungs. The size of inhaled particles is primarily determined by
physical properties of the-agent suspension or agent powder, the
composition of the aerosoli-ed material and the Lype of
dissemination equipment ulilized. However. external circ@-.ISLances
may be of influence. According to Lhe laws of atmospheric
mechanisms influencing an aerosol in its physical and biological
states. particles resulting from the initial evaporation of aerosol
will LheoreLically be larger at high humidity Lhan in dry air.
However, this is difficult Lo prove in field tests.
b. AcrobloICgy
(1) -meteorology and physical decay:
(a) in calm air the aerosolized particles seLEte ouL &L
different rates according to their mass and electrostatic
charges. As an example, fall time from I melre of 50 micron
particles is five minutes, whereas it is theoretically
infinite with an 0.25 micron particle. Consequently, from a
10 Lo 50
microns, the covered distance could reach several kilomelres,
but smaller particles, such as bacteria, often reach greater
distances.
(b) In fact, and irrespective of those sizes, the movement of
an aerosol, once it has been formed, depends largely on Elie
combined eftecls of wind and atmospheric conditions. While
being carried by the wind, the aerosol at the same Lime is
dispersed and dituled by turbulence Of Lhe atmosphere.
Whether the aerosol cloud as a whole will move upward, or will
remain in the vicinity of the ground, Ehus varying its effect,
primarily depends on the stabilicy of the air layer near the
ground. Usually, Lhe air temperature in the atmosphere
decreases as the altitude increases. However, owing to
Lhermal exchange between Lhe air and Lhe ground, a cooler air
layer is frequently formed underneath a mass of warm air. In
such a situation the lower air layer, having a greater
density, does not move upward and the atmosphere is then said
to be in "Stable equilibrium." The vertical temperature
gradient is then positive instead of negative; this phenomenon
is known as "temperature inversion." In such a situation the
persistence of biological aerosol close to@the earth surface
ed. A warm sunny day and a clear sky during
the subsequent night are the most favorable conditions for
creating a stable inversion layer close to the ground level,
since during the night the thermal radiation from the ground
will be so intense that the lower air layer cools more rapidly
12
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Document 109 f:/Week-36/BX003203/DETECTION OF MEDICAL DEFENSE AGAINST BIOLOGICAL MATERIALS/detection of medical defense against biological :1217960927452
Control Fields 17
File Room = sep96_declassified
File Cabinet = Week-36
Box ID = BX003203
Unit = OTSG
Parent Organization = HSC
Folder Title = DETECTION OF MEDICAL DEFENSE AGAINST BIOLOGICAL MATERIALS
Folder Seq # = 21
Subject = DETECTION OF MEDICAL DEFENSE AGAINST BIOLOGICAL
Document Seq # = 1
Document Date =
Scan Date =
Queued for Declassification = 01-JAN-1980
Short Term Referral = 01-JAN-1980
Long Term Referral = 01-JAN-1980
Permanent Referral = 01-JAN-1980
Non-Health Related Document = 01-JAN-1980
Declassified = 17-DEC-1996