Environmental concerns vehicle emissions

The future use of lead may be decided by the resolution of an environmental paradox. Some markets for lead are being phased out because of environmental concerns, eg, the use of tetraethyllead as a gasoline additive. However, a 1990 State of California law and similar laws in nine eastern U.S. states require that 2% of new cars meet 2ero-emission standards in 1998. By 2003 this requirement rises to 10% of new vehicles. Zero emission vehicles are generally accepted to mean electric, ie, battery powered cars, and there is considerable research effort to bring suitable electric vehicles to market by 1998. 

Gasoline and diesel fuels are used worldwide in enormous amounts and are produced by the petroleum industry by oil refining (see Chapter 2). Liquid transportation fuels are conveniently transported, distributed, and dispensed directly into our vehicles and aircraft. Increased environmental concerns did much to begin to assure cleaner burning of our fuels. In the United States, law requires significant reduction of emissions and resulted in lead-free and more recently reformulated gasoline... 

The amount of sulfur in automotive fuels varies presently in the range from 0.01 to 0.10 wt% a typical value is 0.03 wt%. Even in a vehicle with a fuel economy of 27.5 miles/gal, mentioned earlier, the amount of sulfur passing through the catalyst in 50,000 miles will be of the order of 1500 g. Since sulfur emissions from vehicles equipped with oxidation catalysts are a matter of environmental concern (6, 7), one might anticipate some reduction of the fuel sulfur in the future through more extensive desulfurization in refining. On the other hand, such trends may be offset by energy-utilization considerations. However, even a tenfold reduction in fuel sulfur will not completely nullify the effect of this potential poison with respect to some catalysts. 

Over the same period, emissions of nitrogen oxides (NOx) were predicted to remain at current levels or to increase, depending specially on the growth of motor vehicle transport. Such predictions were not initially viewed with any sense of environmental concern because of the accepted nutrient properties of deposited nitrogen and its possible fertilizing action on the terrestrial environment. However, as... 

The buyers of motor vehicles have been substantially positive concerning the need to have cleaner running vehicles. Although the required emission control devices and other mandated safety equipment have increased the cost of new motor vehicles, sales have not been significantly effected. The current environmental awareness and concern are evidence of the general population s new found knowledge and acceptance of both mobile and stationary source emission controls. 

There is also a significant drawback the inherently higher fuel permeability of polymers. The strengthening of environmental regulations (PZEV Partial Zero Emission Vehicle) leads to severe requirements concerning fuel impermeability, needing modification of the techniques now in use. Moreover, some carmakers such as Ford and GM require higher mechanical and thermal resistance, and conductive materials. 

Road dust and run-off. Roads are a potentially important source of environmental contamination. Concerns include NO, PAHs and organo-lead from exhaust emission, and a variety of heavy metals associated with vehicle manufacture and use. 

A number of combustion and chemical production processes contribute to environmental concentrations of PCDD/F. Sources that have traditionally caused the greatest concern include municipal waste incinerators, hospital waste incinerators, bleached chemical wood pulp and paper mills, motor vehicles and wood combustion. We have attempted to represent the most recent data available on PCDD/F emissions from these sources. It should be remembered that the list presented here is by no means exhaustive. Potential sources of TCDD not discussed in the following paragraphs include discharges from metal processing and treatment plants, copper smelting plants and pentachlorophenol production. 

Equivalent reductions in permitted emissions have now been translated into proposed standards for Light Commercial Vehicles and later this year proposals will be made for Heavy Duty Vehicles. European regulations would then become equivalent in the level of emission control to those in the LFSA, including California, reflecting increasing concerns in Europe on the health and environmental effects of pollution from transport. 

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