To Breathe Clean Air

The only completely perfume-free and scent-free city is Halifax, Nova Scotia, although there are other cities discussing the issue, particularly Ottawa. The arguments in favor of making a city scent-free are, among others, that people have a right to breathe clean air and... 

We are all entitled to breathe clean air but until quite recently the only method of heating houses and workshops was by burning coal, wood or peat in open fires. The smoke from these fires created air pollution and the atmosphere in large towns and cities was of poor quality. On many occasions in the 1950s the... 

Mushak, P., Schroeder, C., 1980. Multiple Media Pollutant Exposures and Their Regulation. Report to the National Commission on Air Quality. Contract No. 23a-AQ-6981. Discussed and cited in the National Commission on Air Quality report To Breathe Clean Air, pp. 2.1.9, 2.2-4, 3.1-30, 3.1-34. 

National Commission on Air Quality, 1981. Report To Breathe Clean Air, Washington, DC, March. 

Exterior hoods intended to capture contaminants should be placed as close to contaminant sources as possible. In actual practice, however, the hoods can not always be placed close to the source due to circumstances such as working conditions. In such cases, to enhance the exhaust efficiency of exterior hoods, it is useful to use a low-momentum air supply directed toward the exhaust outlet. The supply airflow, which functions to transport contaminants emitted from sources located at a distance from the exhaust outlet,. should be relatively low with a uniform velocity but high enough so that it is not disturbed by the. surrounding air motions. The advantages of using low-momentum supply with exterior hoods are that (1) a lower supply airflow rate to the workspace is possible, (2) a lower exterior hood exhaust flow rate is possible, and (3) it is possible to supply clean air to the breathing zone of the worker. 

Excretion of hydrogen sulfide was documented after dermal exposure in rabbits. Trunk fiir of rabbits was clipped and left intact or abraded for exposure to hydrogen sulfide gas (unknown concentrations) for 1.5-2 hours the animals then breathed clean air (Laug and Draize 1942). Evidence for the excretion of hydrogen sulfide by the rabbits was a sulfide reaction of the expired air with lead acetate paper (Laug and Draize 1942). Sulfides in the expired air were noted in one rabbit with intact skin after 7 minutes of exposure. This study was limited by the lack of measurement of exposure concentrations and the small number of animals used. 

The Hunza Valley residents were an inspiration to me of what can happen when people live a simple, healthy life using only whole, pure, fresh, and natural foods, getting enough exercise, breathing clean air, and drinking pure water— all in a social context of peace and harmony. Rocine would have loved to see the people of that valley. 

In addition to breathing contaminated air, infants can also be exposed to tetrachloroethylene in breast milk. For example, tetrachloroethylene was present at unspecified levels in seven of eight samples of mother s milk from four urban areas in the United States (Pellizzari et al. 1982). A woman in Halifax, Nova Scotia, who visited her husband daily at the dry cleaning plant where he worked, was found to have tetrachloroethylene present in her breast milk (Bagnell and Ellenberger 1977). This was discovered after her breast-fed infant developed obstructive jaundice, which was attributed to the contaminant. Using a PBPK model, Schreiber (1993) predicted that for women exposed under occupational conditions, breast milk concentrations would range from 857 to 8,440 pg/L. The exposure scenario for the low concentrations was 8 hours at about 6 ppm (exposure concentration of counter workers, pressers and... 

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. 

The final example is shown in Fig. 10.86. Several workers are breaking gates off of castings on the conveyor by hand. Much dust is generated by this operation and the dust rises due to buoyancy. To remove the dust, an exterior hood was placed beside the conveyor and a supply inlet was placed above the workers. The supply airflow is blown toward the breathing zone of the workers and the dust source. In this case, as the workers and the dust source are located within the supply airflow, the airflow functions to supply the workers with clean air and to transport the dust toward the exhaust inlet. The velocity of supply air is relatively low, 1.1 m s , and the exhaust velocity at the hood face is 2.75 m s . The dimensions of the system are indicated in the figure, and the depth of the device is 6.0 m (compare with Sections 10.3.3 and 10.4.6). 

The low-momentum supply system could also be applied to operations inside booths. If a worker must be inside a booth, to protect the breathing zone, a supply inlet with a relatively wide area is placed above the worker and the low-momentum clean air is blown toward the worker. At the same time, the airflow could transport contaminants to the exhaust outlet. 

Clean air and many air contaminants are under normal conditions invisible. It is, however, often desired to actually see the movement of air or the emission and transport of contaminants in order to ensure good air quality.. Methods aimed at the visualization of airflow, contaminants emission to the air, and their transportation out in the workplace and to the breathing zone of the worker are therefore important tools for designers of industrial ventilation systems. 

Both carbon tetrachloride, CC1, (used in dry cleaning and in some lire extinguishers) and mercury, Hg, are liquids whose vapors are poisonous to breathe. If CCh is spilled, the danger can be removed merely by airing the room overnight but if mercury is spilled, it is necessary to pick up the liquid droplets with a vacuum cleaner device. Explain. 

Buildings should be equipped with means of ensuring the occupants have clean air to breathe. This can be accomplished by ... 

Air line respirators are similar to hose respirators, except that they are supplied with compressed air from a clean air source and compressor. They provide complete protection, and because they offer little in the way of breathing resistance, they are more suitable than hose respirators for prolonged use. There are two basic types continuous flow and demand flow. 

Gordon SM, Wallace LA, Pellizzari ED, et al. 1988. Human breath measurements in a clean-air chamber to determine half-lives for volatile organic compounds. Atmos Environ 22 2165-2170. 

The Clean Air Act (CAA), passed in 1970, created a national program to control the damaging effects of air pollution. The CAA Amendments of 1990 went further to ensure that the air Americans breathe is safe. The CAA protects and enhances the quality of the nation s air by regulating stationary and mobile sources of air emissions. 

Ethanol. Alcohol (ethanol) ingestion has repeatedly been associated with potentiation of carbon tetrachloride-induced hepatic and renal injury in humans. In two cases in which men cleaned furniture and draperies with carbon tetrachloride, one man, a heavy drinker, became ill and died (Smetana 1939). His coworker, a nondrinker, suffered a headache and nausea but recovered quickly after breathing fresh air. Both men were subjected to the same carbon tetrachloride exposure, as they had been working in the same room for the same amount of time. In 19 cases of acute renal failure due to carbon tetrachloride inhalation or ingestion, 17 of 19 patients had been drinking alcoholic beverages at about the time of their carbon tetrachloride exposure (New et al. 

FOUND IN Conventional oven cleaners, detergents, furniture polish, and spot removers Made from petroleum and coal, benzene is classified by the International Agency for Research on Cancer as a carcinogen. It s listed in the 1990 Clean Air Act as a hazardous air pollutant, and is on the EPA s Community Right-to-Know list. It s not something you want to add to the air you re breathing at home. 

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