Air Pollution Emissions Issues

The principal concern when using tires for fuel is the effect on emissions. Pollutants of particular concern include criteria pollutants, particulates, metals, and unburned organics. 

Particulate emissions may increase if combustion is not complete. As seen in Tables 1-2 and 1-3, sulfur emissions may decrease if the tires or TDF replace higher sulfur coal, but may increase if tires or TDF replace wood waste containing little sulfur. NOx emissions, likewise, may increase or decrease based on the relative nitrogen content of the fuel. Also, NOx emissions may increase if additional excess air enters the combustion system to facilitate the feed of the tires or TDF. 

Organics, especially polynuclear aromatic hydrocarbons, were measured at a number of facilities. Dioxin and furan formation are also of concern because of their toxic nature. 

The two main process units burning TDF and tires are kilns and boilers. Kilns are usually controlled by electrostatic precipitators (ESP s) or fabric filters. Boilers are usually controlled by venturi scrubbers or ESP s, although some are uncontrolled. 

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