Environmental Impacts from Automobiles | Region 10 | US EPA

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Environmental Impacts from Automobiles

Product Stewardship Information

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There are currently 250,851,833 registered passenger vehicles currently in use in the U.S. In addition, 10 to 11 million vehicles in the U.S. reach the end of their useful lives and are taken out of service every year. The following sections identify and explain some of the key environmental impacts of such large numbers of vehicles both on the roads and in waste streams. The bulk of attention to the environmental impacts from the use of automobiles has centered on emissions, climate change and fuel economy. This sampling of environmental impacts instead focuses on the automobile as a product. It is meant to stimulate preliminary discussion regarding the toxicity and materials management concerns facing the auto industry.

Brake Debris and Tire Particles
The toxic effects of brake debris and tire particles indicate a need for a wider scope of consideration for the environmental impacts of automobiles. These substances raise toxicity levels in nearby soils and, in the case of tire particles, lead to the formation of black carbon. Both pollutants have been shown to cause lung toxicity and account for significant proportions of particulate matter in urban areas. Such impacts have implications for both the use and design of automobiles. Cars should be designed to accommodate less toxic materials and to minimize wear on brakes and tires. Other factors such as sliding speed, temperature, and applied brake pressure must receive careful consideration in both the design and use phases for brakes and tires.

Painting and Coating
Painting and Coating account for 62%, or the largest share of environmental impacts during the manufacture of automobiles. Techniques like “in-mold painting” can reduce discharges of hazardous materials such as nickel, copper, and hexavalent chromium into the atmosphere. Advancements in paint and coating chemistry, as well as reductions in the amount of these materials used would lead to substantial decreases in the negative environmental impacts that currently characterize auto manufacturing.

Vehicle Weight
Many of the environmental impacts of automobiles are directly related to vehicle mass. Widespread concern regarding global climate change and the subsequent charge to reduce vehicle emissions has led to numerous efforts to lower vehicle weight. Increased GHG emissions, however, are not the only rationale for decreasing vehicle mass. For example, heavier vehicles require greater amounts of resistance and brake pressure that lead to larger deposits of brake debris and tire particles in the atmosphere and in nearby soils. Other important considerations regarding vehicle weight and environmental quality include lifecycle impacts associated with the extraction, manufacture, and end-of-life treatment of lighter materials.

Detailed lifecycle analyses are required in order to determine the materials and toxicity benefits of certain uses of steel, light metals, and composites in vehicle construction. For instance, the toxicity and materials impacts of steel body panels must be weighed against the potential for toxic releases during the disposal or incineration of lighter composite materials. The functional life-span of alternative vehicle materials is also an important factor in comparing environmental impacts of heavier and lighter automobiles.

Recyclability and Polymeric Content
Efforts to reduce the environmental impacts of automobiles face an apparent tradeoff between lowering vehicle weight and maintaining a high level of recyclability. The EU’s End-of-Live Vehicles directive (that 85% of vehicle mass be recyclable or reusable by 2015) negates the use of light-weight carbon fiber-reinforced polymers (CFRPs) instead of heavier steel and alloy vehicle components. This is due to the fact that CFRPs are typically incinerated at the vehicle’s EOL stage in the absence of strong incentives for reuse and recycle of such materials. However, some studies have shown that the end-of-life phase comprises only a small fraction of the environmental footprint of CFRPs granted they have a sufficiently long functional life span.

The typical automobile contains a lead-acid battery, which can be returned manufacturers who recover and recycle 93% of the lead. Nonetheless, the remaining 7% accounts for 42,000 tons of lead release into the environment. Complicating the problem is the fact that automobile recyclers and dismantlers may fail to remove and properly handle lead batteries from unwanted vehicles. This could be the result of insufficient enforcement or information deficiencies that accompany language barriers or lack of guidance.

Batteries are a critical component in any automobile, but their importance has increased dramatically in discussions of alternatives to the internal combustion engine. One of the largest hurdles to wide-scale implementation of battery-powered fuel systems for autos is the technology of the batteries themselves. The end-of-life treatment of hybrid vehicle batteries, usually consisting of nickel-hydride or lithium-ion technology, is a pressing concern as hybrids continue to proliferate. Aside from one manufacturer’s dismantling guide (Toyota), there exists little information on how to identify and safely dispose of these materials.

For more information on batteries and other issues related to product stewardship and automobiles, see the following report developed in 2003 for the Minnesota Pollution Control Agency: Product Stewardship Opportunities within the Automotive Industry (PDF)(151pp, 1.4MB).

Auto Shredder Residue
Auto shredder residue (ASR) consists of material leftover after a vehicle is stripped of its economically recoverable elements and then “shredded”. The automotive recycling industry generates 2 billion pounds of ASR per year. It contains rubber, foam, plastic, and cloth contaminated with lead, cadmium, mercury, chrome, PCBs, phthalates, PBDEs and other toxics. While most ASR currently provides cover for landfills, it is increasingly being used as a feedstock in kilns and other fuel-burning operations. ASR represents enormous potential for the release of toxics into the environment. The influx of discarded vehicles resulting from the “Cash for Clunkers” policy exacerbates this potential. The volume and diverse constituency of ASR make it extremely difficult to measure and determine representative samples of its various toxic components.

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URL: https://yosemite.epa.gov/R10/OWCM.NSF/Product+Stewardship/autos-impacts

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