TDF replaces coal in cement kilns and other industrial processes in developed Asian markets such as Japan and South Korea and is widely used throughout Europe and the US. The high calorific value of this material results in reduced greenhouse gas emissions and a detailed analysis of these benefits is available here
The World Business Council For Sustainable Development (WBCSD) in their report, End of Life Tires, make the following comments in relation to both the Greenhouse Gas and additional emissions associated with TDF:
TDF emissions, when tires are burned in a controlled environment, are no greater than those produced by other fuels. The carbon content per unit of energy is less than coal and petroleum coke, offering potential reductions in greenhouse gas emissions. In some situations, using TDF instead of virgin fossil fuels reduces nitrogen oxide, sulfur oxide and carbon dioxide emissions. Natural rubber content in tires (25% or more) is regarded as carbon neutral, as rubber plantations sequester carbon from the atmosphere during their life time. Any ash created generally contains fewer heavy metals than ash from coal combustion. In cement kilns the rubber provides energy and the iron and sulfur are incorporated into the cement. (Iron is normally added to the cement-making process; sulfur is absorbed and converted to sulfates.)
The WBCSD complete report is available WBCSD ELT Report
Additional TDF emissions data can be found Scrap Tyres and TDF emissions data. This includes that, The U.S. EPA testing has shown that (a) tire ash residues contain lesser heavy metals than some coals, and (b) tire combustion results in less NOx emissions compared to burning high-sulfur coal.