Ozone hazards


Typical adsorption poUution appHcations have included odor control in food processing (qv) odor and solvent control in chemical and manufacturing processes such as paints and coating operations, pulp and paper manufacture, and tanneries odor control from foundries and animal laboratories and radioactive gas control in the nuclear industry. Additionally, small carbon-fiHed canisters have been mandated on U.S. automobiles in recent years to reduce evaporative fuel emissions from gasoline engines. Similar adsorption equipment is used to control vapor emissions from fuel-tank filling in states requiring this type of control because of noncompHance with ozone NAAQS regulations. An increasing emphasis on the control of toxic and hazardous organic vapor emissions as presented in the Clean Air Act of 1990, should mean an increase in adsorption appHcations for air poUution  [c.388]

Because of the potential hazards on its exposure to oxygen, isoprene should be stored in an inert atmosphere (nitrogen) in the presence of at least 50 ppm of /-butylcatechol. Because the inhibitor is slowly consumed during storage, it is advisable to analyze the isoprene periodically and to add more inhibitor as needed. Before use it should be flash distilled to remove dimer and inhibitor. In industrial use, inhibitor is often removed by a caustic wash. A dangerous reaction of isoprene with ozone has been reported (126) when one gram of isoprene that was diluted with 50 mL of / -heptane was treated with ozone at -78°C, the resulting product exploded shortly after being removed from the cooling bath however, the product of a similar reaction that was carried out at room temperature did not explode. On storage, isoprene forms cycHc dimers at a slow rate which is not affected by the presence of an inhibitor (35).  [c.469]

Although sprays are useful ia numerous commercial applications, they may create some serious environmental problems because of iaefficient atomization or through misuse. For example, there is a growing concern over poUutant emissions from aircraft and automotive engines that utilize atomizers. PoUutants from engines iaclude carbon monoxide, unbumed hydrocarbons, oxides of nitrogen, and smoke. These poUutants can cause photochemical smog, depletion of the ozone layer, acid rain, and other conditions harmful to human life. Atmospheric poUution may also occur ia spray painting and coating processes. Devices used to atomize solvents and coating formulations must be designed to meet air poUution standards. Because of the potential problems associated with sprays, it has become increasingly important to understand the process of atomization. Liquid atomizers must be properly designed and selected to minimize uimecessary hazards.  [c.327]

Work with asbestos insulating board (superseded by EH 71j Ozone health hazards and precautionary measures Occupational exposure limits (annual)  [c.573]

Plasma spray. Each one of the above treatments for steel adherends has some drawbacks. The chemicals used for solvent cleaning are hazardous and ozone depleting, the effectiveness of etches often depends in unpredictable ways on the underlying microstructure, grit-blasting is ineffective beeause it provides no corrosion protection, and conversion coatings tend to exhibit strengths (in the coating) that are somewhat less than desirable. To overcome these difficulties some recent studies have focused on developing plasma spray coatings as a surface treatment for steels [155-157]. This type of surface treatment has been used extensively to provide improved wear resistance, thermal barriers (for turbine blades), corrosion resistance, etc., in many industrial applications. For adhesive bonding, the prospect of being able to apply a coating having superior corrosion resistance than the underlying steel adherend, while at the same time exhibiting controlled roughness and porosity to improve mechanical interlocking, provided the incentive for the studies.  [c.991]

Volatile Organic Compounds (VOC) organic compounds that vaporize readily and contribute to the development of ozone. Many VOCs are also hazardous air pollutants. See also reactive organic compounds.  [c.552]

Use of Chemical Disinfectants - The most common method of treating water for contamination is to use one of various chemical agents available. Among these are chlorine, bromine, iodine, potassium permanganate, copper and silver ions, alkalis, acids and ozone. Bromine is an oxidizing agent that has been used quite successfully in the disinfecting of swimming pool waters. It is rated as a good germicidal agent. Bromine is easy to feed into water and is not hazardous to store. It apparently does not cause eye irritation among swimmers nor are its odors troublesome.  [c.46]

Tonnage of air emissions, water emissions and liquid and solid effluent and tonnage of hazardous materials released into the environment. These two measures are related to one another. However, the first measure relates the total effluent, including nonpolluting materials. The second measure looks only at the tonnage of hazardous materials contained in the total effluent. Both measures can be important indicators. For example, for solid waste it is important to know the total volume of material for disposal and different upstream treatment techniques may affect the total volume. However, for ozone depleting chemicals, only the quantity of these gases is important and other components such as water vapor may be irrelevant.  [c.126]

Public concerns about air quality led to the passage of the Clean Air Act in 1970 to amendments to that act in 1977 and 1990. The 1990 amendments contained seven separate titles covering different regula-toiy programs and include requirements to install more advanced pollution control equipment and make other changes in industrial operations to reduce emissions of air pollutants. The 1990 amendments address sulfur dioxide emissions and acid rain deposition, nitrous oxide emissions, ground-level ozone, carbon monoxide emissions, particulate emissions, tail pipe emissions, evaporative emissions, reformulated gasoline, clean-fueled vehicles and fleets, hazardous air pollutants, solid waste incineration, and accidental chemical releases.  [c.478]

Reference methods for criteria (19) and hazardous (20) poUutants estabHshed by the US EPA include sulfur dioxide [7446-09-5] by the West-Gaeke method carbon monoxide [630-08-0] by nondispersive infrared analysis ozone [10028-15-6] and nitrogen dioxide [10102-44-0] by chemiluminescence (qv) and hydrocarbons by gas chromatography coupled with flame-ionization detection. Gas chromatography coupled with a suitable detector can also be used to measure ambient concentrations of vinyl chloride monomer [75-01-4], halogenated hydrocarbons and aromatics, and polyacrylonitrile [25014-41-9] (21-22) (see Chromatography Trace and residue analysis).  [c.384]

Chemical Reaction. Reaction of gaseous pollutants can open up new pathways for recovery. Utilization of alkaline scmbbing solutions to collect acidic gases has been discussed. Nitrogen oxides can be decomposed to N2 and O2 by reaction with H2 or CH. Many odors can be controlled by scmbbing organic compounds with solutions of strong oxidants such as potassium permanganate [7722-64-7] KMnO nitric acid [7697-37-2] HNO hydrogen peroxide [7722-84-17, H2O2 hypochlorites and ozone, O. Gas—soHd reactions such as the introduction of hydrated lime into a S02-containing due gas stream (56) are also feasible although these schemes usually fall significantly short of 100% pollutant removal. Dry injection of soHd sodium bicarbonate [144-55-8] NaHCO, has been studied for removal of both SO and NO from due gas, for HCl removal from waste incineration emission (57), and for other hazardous gases from hazardous waste incineration (58). Flue gas humidification generally aids in achieving a more complete gas-soHd reaction. A volatile vapor pollutant can be rendered significantly less volatile by increasing its molecular weight, such as by vapor phase chlorination. An example of a gaseous pollutant control problem that can be changed to a particulate one is the reaction of gaseous HCl with ammonia to produce NH Cl smoke.  [c.389]

Toxicity and Environmental Considerations. Prolonged exposure and skin contact with TNT in the workplace may lead to rashes, skin emptions, and more serious consequences such as nose bleeds and hemorrhage of the skin, as well as mucose and blood disorders. Dust inhalation may result in nausea, vomiting, toxic hepatitis, and anemia. Occupational cleanliness is critically important in TNT manufacture. Wastewater from TNT contains mostiy dissolved TNT and possible traces of dinitrotoluene and isomers of TNT. The water from loading plants generally contains TNT, HMX, RDX, and wax. The washings initially are colorless but turn pink if neutral or basic and exposed to sunlight. The dissolved products are removed by filtration through diatomaceous earth (see Diatomite) and activated carbon. The disposal of the explosive-contaminated carbon by open burning or as landfill ia hazardous waste sites is increasingly unacceptable. An alternative process possible for future appHcation consists of usiag ozone (qv) ia the presence of uv light to decompose the organics ia the pink water. Red water is produced ia the selliting process, and has been either burned ia rotary kiln separators or sold to the paper iadustry. These options are no longer viable, and alternative approaches are under study including process changes and modifications of current iaciaeration technology (189—204).  [c.18]

The most significant environmental and health issues affecting the paint and coatings industry in the 1990s are regulations to lower the VOC content for virtually all types of paints and to restrict the use of certain solvents known as hazardous air pollutants (HAPs) under the federal Clean Air Act. Except for the water in a latex paint or in other water-based coatings, solvents used in house paints are mosdy all VOCs. Several states, along with the U.S. EPA, have implemented environmental regulations to restrict the VOC content of paints, as mandated by the Clean Air Act. These regulations are aimed at minimizing the emission of organic compounds from paints that contribute to the formation of air pollution in the form of smog or ground-level ozone.  [c.547]

Silent electrical discharge at up to 15 kV may be used to create concentrations of about 5% ozone in an oxygen stream, which may then be reacted with a flammable or combustible substance for chemical synthesis. Laboratory preparations in (nonconductive) glass reactors have resulted in occasional explosions via static discharges in the oxygen enriched atmosphere, possibly exacerbated by residual vapor space ozone. An alternative to predilution with nitrogen, which forms nitrogen oxides in the ozonizer, is to add nitrogen downstream of the ozonizer. Other measures are to operate well below the flashpoint of any flammable liquid, typically at approximately -70°C using dry ice mixtures, and to select a more conductive solvent, as opposed to a hydrocarbon such as heptane. During shutdown of the system, a suitable inert gas such as argon should be used to thoroughly purge the system. Precautions should be taken to minimize the vapor space volume, avoid tightly closed containers that will not contain the pressure from an internal deflagration/detonation, and take appropriate measures for personnel protection if a flammable mixture might occur during operation. The hazards of unstable peroxides and ozonides, plus materials of construction suitable for oxygen service should be separately evaluated.  [c.162]

A significant impetus from time to time for developing new methods is dissatisfaction with chlorination. Chlorine affects taste and odor and produces chloramines and a wide variety of other potentially hazardous chlorinated compounds in wastewaters. It seriously threatens the environment with an estimated 1,000 tons per year of chlorinated organic compounds discharged into U.S. waters (chloramines are not easily degradable and pose a hazard to the environment) and is questionable as a drinking water viricidal disinfectant. Ozone s development, on the other hand, could parallel a greater environmental awareness and a resulting demand for higher-quality effluents, as its potential for overcoming these problems is possible.  [c.484]

Ozone has proven to be effeetive against viruses. Franee has adopted a standard for the use of ozone to inaetivate viruses. When an ozone residual of 0.4 mg/I ean be measured 4 minutes after the initial ozone demand has been met, viral inaetivation is satisfied. This property plus ozone s freedom from residual formation are important eonsiderations in the publie health aspects of ozonation. When ozonation is eombined with aetivated earbon filtration, a high degree of organie removal ean be aehieved. Coneerning the toxieity of oxidation produets of ozone and the removal of speeifie eompounds via ozonation, available evidenee does not indieate any major health hazards assoeiated with the use of ozone in wastewater treatment.  [c.489]

Chlororocarbon (CFG) refrigerants are inherently safer with respect to fire, explosion, and acute toxic hazards when compared to alternative refrigerants such as ammonia, propane, and sulfur dioxide. However, they are believed to cause long term environmental damage because of stratospheric ozone depletion.  [c.19]

Table 1 lA presents tabulations of the safety of important refrigerants, but this list does not include aU available refrigerants. Table 11-5 summarizes a limited list of comparative hazards to life of refrigerant gas and vapor. The current more applicable refrigerants from the m or manufacturers of the CFC and HCFC refrigerants and their azeotropes/ blends/mrxtures are included, but the list excludes the pure hydrocarbons such as propane, chlorinated hydrocarbons such as methyl chloride and others, inorganics, ammonia, carbon dioxide, etc. See Table 11-6. The CFC compounds have a longer and more serious ozone depletion potential than the HCFC compounds, because these decompose at a much lower atmospheric level and have relatively short atmospheric lifetimes therefore, they do less damage to the ozone layer. Table 11-7 summarizes alternate refrigerants of the same classes as discussed previously. Table 11-8 correlates DuPont s SUVA refrigerant numbers to the corresponding ASHRAE numbers. Table 1 lA presents tabulations of the safety of important refrigerants, but this list does not include aU available refrigerants. Table 11-5 summarizes a limited list of comparative hazards to life of refrigerant gas and vapor. The current more applicable refrigerants from the m or manufacturers of the CFC and HCFC refrigerants and their azeotropes/ blends/mrxtures are included, but the list excludes the pure hydrocarbons such as propane, chlorinated hydrocarbons such as methyl chloride and others, inorganics, ammonia, carbon dioxide, etc. See Table 11-6. The CFC compounds have a longer and more serious ozone depletion potential than the HCFC compounds, because these decompose at a much lower atmospheric level and have relatively short atmospheric lifetimes therefore, they do less damage to the ozone layer. Table 11-7 summarizes alternate refrigerants of the same classes as discussed previously. Table 11-8 correlates DuPont s SUVA refrigerant numbers to the corresponding ASHRAE numbers.

See pages that mention the term Ozone hazards : [c.40]    [c.275]    [c.240]    [c.409]    [c.793]   
Hazardous chemicals handbook Изд.2 (2002) -- [ c.303 ]