Air Pollution, the Automobile, and Public Health (1988) / Chapter Skim
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Ambient Levels of Anthropogenic Emissions and Their Atmospheric Transformation Products
Ambient Levels of Anthropogenic Emissions and Their Atmospheric Transformation Products
Pages 133-160
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From page 133... ...
E GRAEDEL A TAT Bell Laboratories Concentrations of Atmospheric Trace Constituents / 134 Temporal and Spatial Patterns of Primary Gases / 134 Selected Particle Constituents / 139 Photochemical Products and Unregulated Emittants / 143 Indoor Concentrations / 147 Principal Trace Gases / 147 Minor Emittants and Products / 149 Emittants with Potential Global Influence / 151 Carbon Dioxide / 151 Carbon Monoxide / 152 Methane / 152 Summary / 153 Data Adequacy / 153 Trends / 153 Concentrations / 153 Summary of Research Recommendations / 156 Air Pollution, the Automobile, and Public Health.
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From page 134... ...
. This paper reviews what is known about the measured concentrations of selected atmospheric trace constituents emitted or evolved from human activity, particularly the operation of motor vehicles.
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Despite occasional inadequacies, the data base is quite sufficient to represent atmospheric concentrations and predict their consequences. Atmospheric concentrations of several species, their ranges at different monitoring sites, and their long-term trends have been illustrated with box plots of data from the U
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is approximately equally divided between motor vehicles and stationary combustion activities (U.S. Environmental Protection Agency 1985~.
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Approximate concentration ranges of alkenes in the following different atmospheric regimes: U = urban; 0 = oceanic; M = marshland; F = forest; G = grassland; S = steppes and mountains; D = desert (all of the previous measured within the boundary layer) ; FT = free troposphere (~5 km altitude)
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From page 138... ...
percent of the volatile organic carbon compounds in the atmosphere come from motor vehicles, 37 percent from industrial activities, 15 percent from solid waste and miscellaneous, and 10 percent from volatilization of organic solvents. The total flux of these emissions decreased slightly over the period 1975-1983 and is now believed to be relatively stable.
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From page 139... ...
No analytical instrument is readily available for routine monitoring of NMHC concentrations and concentration trends, although several techniques are available for potential incorporation into such an instrument. It is extremely important to achieve agreement on a satisfactory monitoring technique for NMHC (or some significant fraction thereof)
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Motor vehicle emissions are responsible for perhaps somewhat less than half this amount. The diurnal patterns of reactive aerosol constituents in urban areas have been dem E Q c,' 0.2 en LL Or G C, 0 0.
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Motor vehicles, however, have historically been major sources of lead (Pb) because of the use of Pb compounds as antiknock additives to gasoline.
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From page 142... ...
Stationary combustion sources and motor vehicles may thus be supposed to be about equally responsible for aerosol nitrate; within urban areas, that attributable to motor vehicles probably dominates. Typical concentrations of nitrate fall within the range 1-10 ,ug/m3, with a mean annual value of about 4 ,ug/m3 (Graedel and Schwartz 1977; Harrison and Pio 1983~.
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From page 143... ...
Photochemical Products and Unregulated Emittants The atmospheric species discussed thus far include those that are directly emitted from combustion sources and extensively monitored, either because they are the subject of a standard or as possible preparatory efforts in the establishment of a standard. In this section an attempt is made to discuss other compounds that may be of concern.
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From page 144... ...
The aldehydes are directly emitted from a number of sources, including motor vehicles, but are also produced eff~ciently from small HCs by atmospheric reactions involved in smog chemistry. Measurements of the atmospheric concentrations of formaldehyde are reasonably extensive, although no routine monitoring programs exist.
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This is seen in figure 14, which shows diurnal formaldehyde concentrations in Newark, New Jersey, together with those for CO (an indicator of motor vehicle emissions) and O3 (an indicator of photochemical activity)
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Alcohols are of interest in this review because of the potential for rapidly increasing use in gasohol fuel blends for motor vehicles. If such use should occur, the unburnt alcohols that are emitted will participate in a number of atmospheric chemical processes including the production of organic acids.
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For many trace gases, the concentrations in indoor air reflect indoor sources rather than infiltration of air from outdoors. For a few, injection of outdoor air appears to control indoor concentrations.
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The relationship between indoor and outdoor O3 during smoggy conditions is shown in figure 16. This figure demonstrates that indoor O3 reflects outdoor concentrations, but at a lower level, and that charcoal filtration is effective in removing O3 from indoor environments.
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E Graedel 149 Concentrations of Principal Trace Gases Within Motor Vehicles.
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1984~. There is no indication that formaldehyde from infiltrated outdoor air plays any significant role in establishing indoor formaldehyde concentrations unless there are no indoor sources whatever.
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From page 151... ...
Its emissions from motor vehicles are substantial but are small fractions of the global emission flux. CO2 is not toxic at or near atmospheric concentrations, but its presence in the atmosphere has major effects on biogenic life cycles on the earth because it is a major absorber of the infrared radiation emitted toward space from the earth's surface.
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From page 152... ...
As with CO2, the atmospheric concentrations of CO are steadily increasing (figure 19~. As was pointed out above, motor vehicles are responsible for about two-thirds of all CO emissions and are thus major factors in the global CO increase.
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From page 153... ...
For methanol, ethanol, and manganese, species that may soon be emitted from motor vehicles at much higher rates, the data are extremely sparse. It is important that these compounds be included soon in routine monitoring programs in order to establish baseline concentrations for future reference.
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154 Anthropogenic Emissions and Their Atmospheric Transformation Products Table 1. Typical Ranges and Peak Values for Gaseous and Particulate Species Species Measure ment Ca pability Concentrations Urban Range Urban Indoor Auto Peak Peak Peakb References Emitted gases (ppb)
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Typical concentration ranges of selected atmospheric trace gases in remote areas (R) , urban areas (U)
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From page 156... ...
MODERATE PRIORITY Recommendation 2Measurements of the total particulate loading of the atmosphere Unregulatedgive only the crudest possible idea of the condensed-phase aerosol Species Particlechemistry. A difficult but essential job is to monitor the chemistry Phaseof atmospheric aerosol particles in much more detail than is now being done, concentrating especially on chemical differences as a function of particle size.
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Recommendation 6 The ultimate concern of the epidemiologist dealing with the Personal Exposure effects of atmospheric species is not species concentrations at a Monitors monitoring site, but those encountered by human beings. Personal exposure monitors thus have important future roles to play in health effects research.
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1977. Characterization of aza-arenes in basic organic portion of suspended particulate matter, Environ.
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1983. Characterization of inhalable particulate matter, volatile organic compounds and other chemical species measured in urban areas in New Jersey.
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1985. Personal exposures, indoor-outdoor relationships, and breath levels of toxic air pollutants measured for 355 persons in New Jersey, Atmos.
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