July 24, 2007
Brake linings and tires remain major sources of toxic metals, report says
Stockholm, Sweden – Particles worn off brake linings and tires continue to be major sources of potentially toxic metal emissions in urban areas, despite new regulations and auto industry efforts to reduce use of the metals, according to a new study published in the journal Environmental Science & Technology, and reported by the Green Car Congress.
The study, which focuses on Stockholm, compares metal emissions from brake linings and tires to other metal emission sources during 1995, and from 1998 to 2005. During this period, copper and zinc emissions from brake linings remained relatively unchanged, at high levels that made them a major source of these metals, according to the researchers. Brake linings were also a source of antimony, another toxic metal. By contrast, lead and cadmium emissions from brakes decreased by one-tenth during the period.
The study found that emissions of many metals declined between 1995 and 2005 as manufacturers reduced metal concentrations in tire treads, but tires continued to remain one of the largest sources of zinc, and an important source of cadmium. Depending on the metal, emissions from road traffic accounted for approximately 50 per cent or more of total toxic metal emissions.