Document GByEVQn5K4VpR9jn249oX22n

242 . CHAPTER 13- : . 1946 Guide .Intensive studies on air disinfection have indicated two distinct control measures, (a) suppression of dust and lint, and. (6) disinfection of droplet- nuclei. ' ' ' ' V Well controlled,'large scale tests of the various methods of air sterili zation conducted in barracks V 8 have confirmed the importance of dust control in minimizing the spread of airborne disease, a consideration which has guided the practices of ventilating engineers for a number of years. The importance of the dust factor has been emphasized by many .engineers and has been, convincingly; demonstrated by subsequent bacteriologic studies aboard, ships. . V .. Treatment of floors and bedclothes ` with oil emulsions has proved effective in reducing bacterial dispersion by as much as 90 per cent in JU-l AUC rSCFT OCT iNO* .DEC.. JAM. rCS.iMARjAM..MAY -AIM. ' 100- -100 M 00Sao- AU. RCSPMATOffr / \ -o' -0. $ 70- - 70 S o- - < 30u k 40- / s. \ INFLUENZA / ANO v / / 1 ORtPPC'X^-^l \ !\ \\ y\ 1 -o -SO -4 !'z J *103-~ / `OISEASO1 \ -30 . . / . or ` ./ /T PHARYNX' \ ,\- -,*o . ANO TONSILS - 10 -U-- .. BRONCHITIS-- - s. 3- PNEUMONIA ^ ' 4 J - i: . -s JtZ. AUO.aCPX OCZ IKPfc OCC. 4AK FEB. MAR. APR.*MAY 4UN. . MONTH IN WHICH MSABIUTT`OCCAN I _ Occurrence, of diseases causing disability for. 8 consecutive days or longer in a etoud of, 100 000 waee earners`(10 per. cent women) in different industries. ' \'1' ' - 1 Graph obtained from Dean K. Bnmdage, U.' & Public' Hekltti Service'.; 11 : ` ./: (- ; Fig.; 1 Study of Average Monthly Frequency 1921;-1926 inclusive) of , ... ; . Specified Respiratory'Diseases3 .. . , Armjr barrciks and station hospitals18.' * The incidence of acute respiratory infections was from 10 to 30 per cent lower in barracks with'oiled'flbor$ and bedclothes than it was in control barracks'which received no special treatment.. : ' ;/ No simple method for disinfecting drqplet-huclei has yet been' devised: Under favorable laboratory conditions, propylene glycol in concentrations 6f 0.07 to 0.14 milligrams per liter, and' trieth'ylerie-glycol in a concen- tration of 0.0.045 milligrams per liter Were highly getiniddal for most airborne'Jbacteria in clean air when the relative humidity was: between 40 and 60 per cent 9-10> ". Under practical conditions, however, particular!^ in the pretence of dust in the air, glycol effectiveness is much reduced:. The use of other chemical aerosols that have been tried-is limited by their toxicity, odor, or destructiveness to-fabrics and metals..' Ultraviolet radiation of floors and upper air has proved more effective Air Conditioning in the Prevention'and Treatment of Disease____________ 343, than glycol aerosols in`reducing respiratory illness. In barracks housing naval recruits,.-hospital admissions- for respiratory infections (mostly catarrhal fever) were 25 per cent lower in a group of men exposed to ultra violet radiation--(2537 Angstrom Units, 1 to 7 ergs per (cm1) (sec) at bed level)--than they were in adjacent control barracks without :ultra-. violet radiationa. . A combination of ultraviolet radiation and ; dust control measures is believed to be more effective than when either one of the two is used alone, but the proof for this has yet to come, . VALUE OF AIB COOLING UNDER TROPICAL CONDITIONS The commissioning of a class of naval hospital ships with all,.wards, laboratories and living spaces air. cooled is a notable achievement to provide better treatment of patients, especially those, suffering from, extensive burns, by control of environmental factors. Although statistics are not at hand to indicate the deaths or retarded recoveries of patients due'to lack of air cooling in ships*operating in"tropical."waters, it' is generally agreed among competent observers that high temperature and humidity aremajorfaetbrs in prolonging disability and 'increasing, mortality of the sick and injured: Physiologic data obtained on healthy men, mbreover.' show the large loss of-body fluids', and the stress, on' the . cardiovascular system in terms of increased bulse rate when these men are> continuously subjected to high temperatures. Even at rest'about 50 cc of fluid per hour are lost as sweat18 through intact skin.In burn patients the difficulty, encountered in temperate climates, of maintaining fluid and electrolyte:balance-is tremendously augmented by the .addi- .tionalevaporative.fluid loss in hot environments. . Frequently from150 to 75 per cent of personnel aboard naval vessels operating in-tropical waters'are afflicted with heat rash to a degree that interferes, with rest and sleep. In carefully controlled experiments 18 it was possible to produce a fulminating ' type of rash in all men living continuously at an effective temperature of' 85 (90 F dry-bulb and 83 F - wet-bulb). In the control gtoup, 12 out of 24 hr were spent in a relatively cool- atmosphere of 75 ET. (80.F dry-bulb, and.70. F wet-bulb). These y