Air-breathing

Eor toxic materials, it usually is advisable to provide ventilated sampling hoods or breathing-air stations and masks, to assure that the sampler is adequately protected from toxic or flammable vapors and dusts. Special provision for access to and exit from sampling points also may be needed at elevated locations and to avoid tripping or bumping ha2ards and to ensure that the sampler does not transverse areas not intended as walkways, eg, tank covers or roofs. 

The radiological hazard of tritium to operating personnel and the general population is controlled by limiting the rates of exposure and release of material. Maximum permissible concentrations (MPC) of radionucHdes were specified in 1959 by the International Commission on Radiological Protection (79). For purposes of control all tritium is assumed to be tritiated water, the most readily assimilated form. The MPC of tritium ia breathing air (continuous exposure for 40 h/wk) is specified as 185 kBq/mL (5 p.Ci/mL) and the MPC for tritium in drinking water is set at 3.7 GBq/mL (0.1 Ci/mL) (79). The maximum permitted body burden is 37 MBq (one millicurie). Whenever bioassay indicates this value has been exceeded, the individual is withdrawn from further work with tritium until the level of tritium is reduced. 

Employees should never breathe air containing a level of asbestos which exceeds these limits. Moreover the level should always be reduced so far as it reasonably can be. Use should be made of ... 

Identification of the pollutant source and installation of the local exhaust is critically important. For example, an improperly designed local exhaust can draw other contaminants through the occupied space and make the problem worse. The physical layout of grilles and diffusers relative to room occupants and pollutant sources can be important. If supply diffusers are all at one end of a room and returns are all at the other end, the people located near the supplies may be provided with relatively clean air while those located near the returns breathe air that has already picked up contaminants from all the sources in the room that are not served by local exhaust. 

It can sometimes be easier, inside a specific volume, to use supply than to use exhaust air to control contaminants because of the much longer range of influence air from a supply opening has when the openings have the same size and the same airflow rate. For some contaminants and in some processes it may also be necessary to supply additional breathing air to the workers and this air could then also be used to control and transport contaminants. For spot cooling of workers or work pieces it is possible to use point jets originating from specific supply inlets. 

Asphyxiant Simple asphyxiants are inert gases which deplete the oxygen supply in the breathing air to below the critical value of J8% by volume, such as gaseous fuels or nitrogen. Chemical asphyxiants, such as carbon monoxide and hydrogen cyanide, have a direct biological effect. 

Which difference could account for the fact that a diver is much less likely to suffer from the bends if he breathes a mixture of 80% helium and 20% oxygen than if he breathes air (The bends is a painful, sometimes fatal, disease caused by the formation of gas bubbles in the veins and consequent interruption of blood flow. The bubbles form from gas dissolved in the blood at high pressure.)... 

Methyl parathion can enter your body if you eat food or drink water containing it if you swim, bathe, or shower in contaminated water if you touch recently sprayed plants or soil if you touch contaminated soil near hazardous waste sites or if you breathe air that contains methyl parathion, such as near factories or recently sprayed farm fields (or in recent accounts of the illegal use of methyl parathion, if you breathe air or touch contaminated surfaces inside homes where methyl parathion has been used to kill insects). By any means of exposure, methyl parathion goes into your body quickly and gets into your blood. From your bloodstream, methyl parathion goes to your liver, brain, and other organs. Your liver changes some of methyl parathion to a more harmful chemical called methyl paraoxon. Both methyl parathion and methyl paraoxon can bind to enzymes of your nerves within minutes or hours. Your liver breaks down methyl parathion and methyl paraoxon into less harmful substances. These less harmful substances leave your body in urine within hours or days. For more information, see Chapter 3. 

Children can be exposed to endosulfan by eating food contaminated with the pesticide, by accidentally ingesting the pesticide if it is stored around the house, or by breathing air contaminated with the pesticide if it is sprayed on nearby fields. There are no known unique exposure pathways for children. We do not know if children s intake of endosulfan per kilogram of body weight is different than that of adults. 

NIOSH recommends that workers should not breathe air that contains more than 0.1 milligram (mg) of endosulfan per cubic meter of air (0.1 mg/m ) during a 10-hour workday, 40-hour workweek. For more information on limits and standards for endosulfan exposure, see Chapter 7. 

Trichloroethylene enters your body when you breathe air or drink water containing it. It can also enter your body if you get it on your skin. You could be exposed to contaminated water or air if you live near or work in a factory that uses trichloroethylene or if you live near a waste disposal site that contains trichloroethylene. If you breathe the chemical, about half the amount you breathe in will get into your bloodstream and organs. You will exhale the rest. If you drink trichloroethylene, most of it will be absorbed into your blood. If trichloroethylene comes in contact with your skin, some of it can enter your body, although not as easily as when you breathe or swallow it. 

The sense of smell, with which we can enjoy a bursting rosebud on a summer s day, or a fine Cabernet, is a relatively recent evolutionary acquisition. For most of evolutionary time our ancestors did not breathe air and gained information about their surroundings by tasting their aquatic environments. The so-called olfactory rosettes in the heads of... 

Have available and use as appropriate - rubber suits and gloves full-body chemical suit self-contained breathing air... 

Passive smoking Non-smokers who breathe air polluted by tobacco smoke can... 

Annanmaki (1978) studied the transfer of Rn from water to air. By applying occupancy factors for different areas in the house, he found that 1 Bq m 3 in household water would result in 1.4x10 Bqm 3 in breathing air. By applying this transfer factor, the highest Rn-222 concentrations in air due to well water is 1000 Bq m 3. 

Air intakes to heating and ventilation systems, air compressors for process, instrument and breathing air, and to prime movers for gas compressors, power generation and pumps should be located as far as practical from contamination by dust, toxic and flammable materials release sources. They should not be located in electrically classified areas. If close to possible vapor releases (as confirmed by dispersion analyses( they should be fitted with toxic or combustible gas detection devices to warn of possible air intakes hazards and snutdown and isolate the incoming air ductwork and fans. 

Breathe air of normal composition, but at a greater overall pressure. An example of this approach is the diver who breathes underwater while fitted out with SCUBA gear. 

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