Emission standards effects

The physical state of a pollutant is obviously important a particulate coUector cannot remove vapor. Pollutant concentration and carrier gas quantity ate necessary to estimate coUector si2e and requited efficiency and knowledge of a poUutant s chemistry may suggest alternative approaches to treatment. Emission standards may set coUection efficiency, but specific regulations do not exist for many trace emissions. In such cases emission targets must be set by dose—exposure time relationships obtained from effects on vegetation, animals, and humans. With such information, a Ust of possible treatment methods can be made (see Table 1). 

Effective with the 1982 model year, particulate matter from diesel vehicles was regulated by the U.S. Environmental Protection Agency for the first time, at a level of 0.37 gm km . Diesel vehicles were allowed to meet an NO level of 0.93 gm km under an Environmental Protection Agency waiver. These standards were met by a combination of control systems, primarily exhaust gas recirculation and improvements in the combustion process. For the 1985 model year, the standards decreased to 0.12 gm of particulate matter per kilometer and 0.62 gm of NO per kilometer. This required the use of much more extensive control systems (1). The Clean Air Act Amendments of 1990 (2) have kept the emission standards at the 1985 model level with one exception diesel-fueled heavy trucks shall be required to meet an NO standard of 4.0 gm per brake horsepower hour. 

Reduction of exhaust emissions is being tackled in two ways by engineers, including precombustion and postcombustion technology. One of the most effective methods now being researched and adopted includes use of synthetic fuel made from natural gas. This fuel is crystal clear, and just like water, it has no aromatics, contains no sulfur or heavy metals, and when used with a postcombustion device such as a catalytic converter any remaining NO, or other emissions can be drastically reduced. Estimates currently place the cost of this fuel at 1.50 per gallon, with availability in 2004 to meet the next round of stiff EPA exhaust emission standards. 

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... 

NESHAP National Emissions Standards for Hazardous Air Pollutants emission standards for specific source categories that emit or have the potential to emit one or more hazardons air pollutants the standards are modeled on the best practices and most effective emission reduction methodologies in use at the affected facilities. 

As a result of atmospheric pollution levels that exceed the National Ambient Air Quality Standards (NAAQS) in many parts of the United States, both the federal government and the State of California have implemented standards for exhaust and evaporative emissions from new vehicles (see Exhaust control, AUTOMOTIVE). The first of these standards went into effect in 1968 and mandated that the vapors from the vehicle crankcase be routed back through the engine and burned. Since then, the standards have continued to grow stricter. Table 7 shows the federal exhaust emission standards and Table 8 shows the more stringent California standards. California has mandated that starting in 1998 a certain percentage of new vehicles sales must be zero emissions vehicles (ZEV). 

In 1995, the amendments to the Clean Air Act included requirements for maximum achievable control technology (MACT) for pollutants, including dioxins and metals. The EPA has since promulgated regulations that will have to be met by a modified baseline process for the Pueblo site (EPA, 1999). In addition, EPA is reviewing the effects of dioxins on human health because some evidence indicates dioxins may be more harmful in the food chain than previously thought (Kaiser, 2000). If dioxin emission standards are modified, analytical procedures will need to be reviewed. 

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