Air concentrations

Mild exposure to HF via inhalation can irritate the nose, throat, and respiratory system. The onset of symptoms may be delayed for several hours. Severe exposure via inhalation can cause nose and throat bums, lung inflammation, and pulmonary edema, and can also result in other systemic effects including hypocalcemia (depletion of body calcium levels), which if not promptly treated can be fatal. Permissible air concentrations are (42) OSHA PEL, 3 ppm (2.0 mg/m ) as E OSHA STEL, 6 ppm (5.2 mg/m ) as E and ACGIH TLV, 3 ppm (2.6 mg/m ) as E. Ingestion can cause severe mouth, throat, and stomach bums, and maybe fatal. Hypocalcemia is possible even if exposure consists of small amounts or dilute solutions of HE. 

The threshold limit value—time integrated average, TLV—TWA, of chlorine dioxide is 0.1 ppm, and the threshold limit value—short-term exposure limit, STEL, is 0.3 ppm or 0.9 mg /m of air concentration (87,88). Chlorine dioxide is a severe respiratory and eye irritant. Symptoms of exposure by inhalation include eye and throat irritation, headache, nausea, nasal discharge, coughing, wheezing, bronchitis, and delayed onset of pulmonary edema. Delayed deaths occurred in animals after exposure to 150—200 ppm for less than one hour. Rats repeatedly exposed to 10 ppm died after 10 to 13 days of exposure. Exposure of a worker to 19 ppm for an unspecified time was fatal. The ingested systemic effects of low concentration chlorine dioxide solutions are similar to that of chlorite. 

The specific requirements to complete the NSR process will vaiy depending on the source location and characteristics, the federal and state regulations which apply, the compliance status of the facihty if it is existing, and the nature of other sources in the area. Atmospheric dispersion modehng is often necessary to determine the maximum offsite ambient air concentrations of the various pollutants that will be... 

One hundred people will likely be exposed to air concentrations above the emergency response planning guidelines (e.g., ERPG-2, see Glossary). 

A system of guidelines for air concentrations of toxic materials prepared by the American Industrial Hygiene Association. An ERPG is the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to 1 hour with the following results ... 

Aluminum appears to be resistant to corrosion from SO2 at ambient air concentrations. Aluminum alloys tend to form a protective surface film... 

Polytetrafluoroethylene decomposition products thermal decomposition of the fluorocarbon chain in air leads to the formation of oxidized products containing carbon, fluorine and oxygen. Because these products decompose in part by hydrolysis in alkaline solution, they can be quantitatively determined in air as fluoride to provide an index of exposure. No TLV is recommended pending determination of the toxicity of the products, but air concentration should be minimal. (Trade names Algoflon, Fluon, Teflon, Tetran.)... 

Conduct work in designated controlled areas (e.g. in UK these are areas in which instantaneous dose rates >7.5 pSv/hour occur, or where employees may exceed 6 mSv annual dose limit, or where air concentration or surface contamination exceeds specified levels). 

Concentration of contaminant in air Concentration of contaminant inside facepiece... 

Extinguishing Agents Dry chemical, carbon dioxide, water fog, chemical foam Fire Extinguishing Agents Not To Be Used None Special Hazards of Combustion Products Not pertinent Behavior in Fire Vapor from molten benzoic acid may form explosive mixture with air. Concentrated dust may form explosive mixture in air Ignition Temperature (deg. F) 1,063 Electrical Hazard Not pertinent Burning Rate Not pertinent. 

Finally, for situations in which it is not clear that exposure is and will continue to be below the limit values, a detailed survey with a measurement strategy is required. The methods used are based mostly on instruments for sampling the environment in order to obtain reliable measurements of workplace air concentrations. In general, the measurement strategy must consider the most efficient use of resources for the purpose of obtaining quantitative data on exposures by having a clear idea of what the data will be used for or whether it meets the specified need. For example, if the data pertain to peak exposures, these peaks have to be assessed according to the STEL requirements, if any. 

By assuming the supply air concentration to be zero, since usually there are quite different contaminants in the outside air and from the source, and that the initial concentration also is zero, the time-dependent solution is the following,... 

At least three factors must be considered when using Eq. (10.132). The first is that the room air is seldom well mixed the second is that the emission rate is usually unknown and the third is that measurement of is often very difficult, especially in spaces where a mixture of mechanical and natural ventilation is used. If the room air is poorly mixed, a sampling strategy is needed in order to determine the room air concentration (C,). There exist different strategies for this, and two are as follows ... 

The contaminant concentration measurement in the general ventilation exhaust will provide the best average value for room air concentration (CJ. 

The room air concentration (Q) can be determined by measuring the concentration for a grid of points around the room. 

Exposure limits Guidelines for worker exposure to physical agents and hazardous chemicals, usually expressed as an allowable time of exposure or an air concentration below which health hazards are unlikely to occur among most exposed workers. 

For offshore locations where ignitible gas-air concentrations are neither continuously present nor present for long periods, API RP 14F also allows type MC cable with a continuous aluminum sheath and an outer impervious jacket (such as PVC) and armored cables satisfying ANSI/ Institute of Electrical and Electronic Engineers (IEEE) Standard No. 45. API RP 14F does not recommend IMC for offshore installations and cautions users that installations of MI cable require special precautions. The insulation of MI cable is hygroscopic (able to absorb moisture from the atmosphere). 

When using animal inhalation e.xpcrimcnts to estimate lifetime human risks for partially soluble vapors or gases, the air concentration (ppm) is generally considered to be the equivalent dose between species based on cqui alcnt c.xposure times (measured as fractions of a lifetime). For inhalation of particulates or completely absorbed gases, the amount absorbed per unit of body surface area is considered to be the equivalent dose between species. 

C, = amnial average air concentration of pollutant i UR, = unit risk value by inhalation for pollutant i L = operational lifetime of a facility, yr usually assumed to be 70 year... 

In areas of agricultural methyl parathion usage, both outdoor and indoor air levels of methyl parathion of approximately 12 ng/m have been measured, and household dust was found to contain 21 ppb of methyl parathion. Outdoor and indoor air concentrations of methyl parathion as high as 0.71 and 9.4 pg/m, respectively, have been measured at the homes of individuals employed as pesticide formulators. 

Associations between urinary 4-nitrophenol and indoor residential air and surface-wipe concentrations of methyl parathion have been studied in 142 residents of 64 contaminated homes in Uorain, Ohio (Esteban et al. 1996). The homes were contaminated through illegal spraying. A mathematic model was developed to evaluate the association between residential contamination and urinary 4-nitrophenol. There were significant positive correlations between air concentration and urinary 4-nitrophenol, and between maximum surface-wipe concentrations and urinary 4-nitrophenol. The final model includes the following variables number of days between spraying and sample collection, air and maximum surface wipe concentration, and age, and could be used to predict urinary 4-nitrophenol. 

Atmospheric concentrations of methyl parathion following application of the pesticide to tobacco fields were studied by Jackson and Lewis (1978). They found that levels of methyl parathion decreased rapidly following application of either the emulsifiable concentrate or the microencapsulated form. Air concentrations for the emulsifiable concentrate ranged from 7,408 ng/m immediately following application to 13 ng/m 9 days later. The corresponding measurements for the microencapsulated form were 3,783 and 16 ng/m. ... 

EL = emissions level ERA = Environmental Protection Agency HSDB = Hazardous Substances Data Bank lARC = International Agency for Research on Cancer IRIS = Integrated Risk Information System NIOSH = National Institute of Occupational Safety and Health OEL = occupational exposure limit OSHA = Occupational Safety and Health Administration PEL = permissible exposure limit RAC = reference air concentration REL = recommended exposure limit RCRA = Resource Conservation and Recovery Act RfD = reference dose TLV = threshold limit value TWA = time-weighted average WHO = World Health Organization... 

Baker LW, Fitzell DL, Seiber JN, et al. 1996. Ambient air concentrations of pesticides in California. Environ Sci Technol 30 1365-1368. 

Arizona Average acceptable ambient air concentrations (1 hour) (24 hours) 2.4 pg/m 0.8 pg/m NATICH 1992... 

Connecticut Average acceptable ambient air concentrations — (8 hours) 2 pg/m ... 

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