Air contamination

Air Contaminants—Permissible Exposure Limit," Title 29 Code of Federal Regulations Part CFR 1910.1000, OSHA, 1989, p. 3112. 

Air contaminants are emitted to the indoor air from a wide variety of activities and consumer products, some of which are summarized in Table 11. Most indoor activities produce some types of pollutants. When using volatile products or engaging in the activities Hsted, care should be exercised to minimize exposure through proper use of the product and by providing adequate ventilation. 

Methanol use would also reduce pubHc exposure to toxic hydrocarbons associated with gasoline and diesel fuel, including ben2ene, 1,3-butadiene, diesel particulates, and polynuclear aromatic hydrocarbons. Although pubHc formaldehyde exposures might increase from methanol use in garages and tunnels, methanol use is expected to reduce overall pubHc exposure to toxic air contaminants. 

Physiological Classifications of Contaminants. The physiological classification of air contaminants is difficult, because the type of action of many gases and vapors depends on concentrations (55). For example, a vapor at one concentration may exert its principal effect as an anesthetic but, at a lower concentration, the same vapor may iujure the nervous system, the hematopoietic (blood-forming) system, or some visceral organ (see Toxicology). 

Occupational Safety andHealth Standards, Tide 29, Subtitie B, Chapt. XVII, Part 1910, Subpart Z, Paragraph Air Contaminants, and Paragraph 1200, Ha iard Communication, U.S. Department of Labor, Occupational Safety and Health Administration, Washington, D.C., 1991. 

Industry Process of operation Air contaminants emitted Control techniques... 

Soiling of goods. Clothes, real estate, automobiles, and household goods can easily be soiled by air contaminants, and the more frequent cleaning thus required can become expensive. Also, more frequent cleaning often leads to a shorter life span for materials and to the need to purchase goods more often. 

Smith, W, H., "Air Pollution and Forests Interaction between Air Contaminants and Forest Ecosystems," 2nd ed. Springer-Verlag, New York, 1990. 

Hering, S. V., "Air Sampling Instruments for Evaluation of Air Contaminants." ACGIH, Cincinnati, OH, 1989... 

Air contaminant releases from hazardous waste sites can occur from wastes placed aboveground or belowground. The following are categories of air contaminant releases ... 

The EPA Hazardous Ranking System computes a numerical score for hazardous waste. If the score exceeds a predetermined value, the waste site is placed on the National Priority List (NPL) for Superfund cleanup. Discuss the pros and cons of such a ranking system. Describe a possible situation in which an air contaminant is controlled but the control system used transfers the contaminant problem to another medium, such as water or soil. 

Air contaminant (p,g m Desirable range Acceptable range Idlerablc range... 

Bayer, C. W., and Black, M. S. (1988a) Indoor Air Quality Evaluations of Three Office Buildings Two of Conventional Construction Designs and One of a Special Design to Reduce Indoor Air Contaminants. Georgia Institute of Technology, Athens, GA. 

Experience has shown that the lives of both uncoated and coated blades depend to a large degree on the amount of fuel and air contamination. This effect is shown in Figure 11-8, which illustrates the effect of sodium, a common contaminant, on blade life at 1600 °F (871 °C). The presence of increased levels of contaminants give rise to an accelerated form of attack called hot corrosion. 

Prevent air contamination in high-pressure reactions since the nitrogen dioxide which could form may pose ignition and detonation hazards. 

Table 10.12 Selected examples of sampling techniques for air contaminants...

A summary of several Web site sources that provide extensive data bases on the chemical and physical properties, as well as health risk effects associated with air contaminants. 

HVAC the HVAC system is not able to control existing air contaminants and ensure thermal comfort (temperature and humidity conditions that are comfortable for most occupants). 

Indoor air contaminants can originate within the building or be drawn in from outdoors. If contaminant sources are not controlled, problems can arise, even if the HVAC system is properly designed and well-maintained. Sources can be from outside the building from operating equipment, from human activities, and other or miscellaneous sources. Sources outside a building include contaminated outdoor air, emissions from nearby sources, soil gas, or moisture or standing water. 

Ventilation modification is often used to correct or prevent indoor air quality problems. This approach can be effective either where buildings are underventilated or where a specific contaminant source cannot be identified. Ventilation can be used to control indoor air contaminants by ... 

The following is a brief introduction to making measurements that might be needed in the course of developing an lAQ profile or investigating an lAQ complaint. Emphasis has been placed on the parameters most commonly of interest in nonresearch studies, highlighting the more practical methods and noting some inappropriate tests to avoid. Most of the instruments discussed in this section are relatively inexpensive and readily available from many local safety supply companies. Air contaminants of concern in lAQ can be measured by one or more of the methods described below. 

This exposure is not excessive since 7 ppm is below the 8-hour time-weighted average of 10 ppm. Mixtures of air contaminants are additive and calculated in the manner described previously that is, the fractions (concentration divided by limit for each material) are added together and if the sum does not exceed unity, the exposure is not excessive. 

A characteristic of the air contamination in most occupational environments is that there is most always a continual change in concentration with respect to time and... 

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