Smoke opacity

In April of 1998, the EPA published a final rule for emission of oxides of nitrogen (NOx), hydrocarbons (EIC), carbon monoxide (CO), particulate matter (PM), and smoke opacity for newly manufactured and rcmanufacturcd locomotives. The rulemaking took effect in 2000 and is estimated by the EPA to cost the railroads 80 million per year—about 163 per ton of NOx reduced, according to EPA figures. The emissions standards for the several pollutants will be implemented in three tiers—for locomotives... 

Recorders measure steam flow, air flow, FW flow, drum water level, steam temperatures, flue gas temperatures, flue gas analysis and smoke opacity. 

Smoke opacity is another increasingly important characteristic measured by optical density. Fire-retardant additives can be halogenated or halogen-free, which reduces the corrosivity, toxicity and pollution risks. 

In many states, regulations only require that hospital incinerators not create a public nuisance usually recognized as odors and smoke opacity. Disposal costs for these medical wastes are becoming stiffer, just as surely as they are for infectious and other hazardous/toxic wastes. This adds another incentive to incinerate. It may be possible that a good deal of hospital waste could be separated, reduced, and recycled. While infectious waste is obviously not recyclable, the amount of waste designated infectious can be greatly reduced by separating materials to avoid excess contamination [74]. 

The chief transportation target of the 1970 Clean Air Act was the automobile hence, stringent regulations were directed at automakers. Visible smoke from diesel engines used in heavy-duty vehicles was regulated first. There was a concern that smoky stacks would result in many more complaints as motorists had to pay more for cleaned-up cars. Thus, the first smoke opacity laws were based on the appearance of smoke to the eye. Although the health effect was debated at the time, there was little doubt that smoke obscures visibility. This alone was a sufficient basis for California and U.S. regulations. In 1970,... 

The presence of ammonium polyphosphate and melamine cyanurate filler causes a slight worsening of the physical and mechanical properties of PU and PIR foams but the fire behaviour of flame retarded foams is better than that of unfilled foams. In particular the use of the previously mentioned mixture, which produces a synergistic effect causes a significant improvement of the fire performance. This is characterised by a remarkable decrease of RHR and weight loss without worsening smoke opacity and toxicity [183]. 

Limits on emissions are both subjective and objective. Subjective limits are based on the visual appearance or smell of an emission. Objective limits are based on physical or chemical measurement of the emission. The most common form of subjective limit is that which regulates the optical density of a stack plume, measured by comparison with a Ringelmann chart (Fig. 25-1). This form of chart has been in use for over 90 years and is widely accepted for grading the blackness of black or gray smoke emissions. Within the past four decades, it has been used as the basis for "equivalent opacity" regulations for grading the optical density of emissions of colors other than black or gray. 

Opacity reduction is the control of fine particulate matter less than 1 ixm). It can be accomplished through the application of the systems and devices discussed for control of particulate matter and by use of combustion control systems to reduce smoke and aerosol emission. In addition, operational practices such as continuous soot blowing and computerized fuel and air systems should be considered. 

A 1-year follow-up of 103 miners and millers of talc ore free from asbestos and silica showed an association between exposure and small opacities on chest radiographs the annual loss in FEVi and FVC was greater than expected and could not be wholly attributed to cigarette smoking." However, effects on pulmonary function in nonsmokers was not associated with lifetime or current talc exposure."... 

Roessler, D. M., and F. R. Faxvog, 1979b. Opacity of black smoke calculated variation with particle size and refractive index, Appl. Opt., 18, 1399-1403. 

These are similar to nephelometers, except that they measure the attenuation of a light beam due to the combined effects of absorption and scattering by the sample. The instrument consists of a light source, a collimator and a photo-detector. The most common application is the measurement of smoke density in chimney stacks. In this case the optical surfaces exposed to the smoke are kept clean by flows of clean air. The density of the smoke is expressed in terms of per cent opacity, per cent transmittance or optical density, where ... 

The extinction of a light beam or incident radiation associated with a cloud of particles basically involves a measure of a moment of the particle number-size distribution roughly proportional to the surface concentration. The extinction of a light beam is well-developed basis for semi-quantitative measurement of particles suspended in gases. Devices for these purposes, including smoke photometers, have been available commercially for many years. They may take many forms, one of which is the transmissome-ter, or opacity instrument. 

Barnhart S, Thomquist M, Omenn GS, et al. 1990. The degree of roentgenographic parenchymal opacities attributable to smoking among asbestos-exposed subjects. Am Rev Respir Dis 141 1102-1106. 

Blanc P. 1991. Cigarette smoking, asbestos, and parenchymal opacities revisited. Ann NY Acad Sci 133-141. 

Hnizdo E, Sluis-Cremer GK. 1988. Effect of tobacco-smoking on the presence of asbestosis at postmortem and on the reading of irregular opacities on roentgenograms in asbestos-exposed workers. Am RevRespirDis 138 1207-1212. 

Kilbum KH, Warshaw RH. 1992b. Severity of pulmonary asbestosis as classified by international labour organization profusion of irregular opacities in 8749 asbestos-exposed American workers Those who never smoked compared with those who ever smoked. Arch Intern Med 152(2) 325-327. 

Weiss W. 1984. Cigarette smoke, asbestos, and small irregular opacities. Amer Rev Respir Dis 130 293-301. 

Zitting AJ, Kaqalainen A, Impivaara 0, et al. 1996. Radiographic small lung opacities and pleural abnormalities in relation to smoking, urbanization status, and occupational asbestos exposure in Finland. J Occup Environ Med 38 602-609. 

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