NEW YORK ( TheStreet) -- ETF Securities is launching the first U.S.-traded physically-backed platinum and palladium ETFs today. The highly anticipated ETFS Physical Platinum Shares ( PPLT) and ETFS Physical Palladium Shares ( PALL) will expand the lineup of popular commodities funds designed to give investors access to the price of precious metals. As I noted previously, platinum and palladium are unique precious metal holdings that stand to benefit from rapid expansion abroad. More than half of the supply of palladium and platinum goes into the construction of catalytic converters, which convert harmful gases from auto emissions into less harmful substances. As the rapidly growing markets in China and India begin to develop emissions standards, platinum and palladium will be in high demand. PPLT and PALL will join the ranks of other popular physically-backed ETF Securities funds. Already trading are the ETFS Physical Silver Shares ( SIVR) fund and ETFS Physical Swiss Gold Shares ( SGOL), launched in July and September respectively. If the rapid growth of SIVR and SGOL is any indication of investor interest, PPLT and PALL could quickly attract volume. While PPLT and PALL are the first U.S.-traded funds to track physical stockpiles of platinum and palladium, other platinum and palladium-tracking securities have already premiered with varying success. The UBS E-TRACS CMCI Long Platinum Total Return ETN ( PTM), UBS E-TRACS CMCI Short Platinum Excess Return ( PTD), and the Dow Jones-UBS Platinum Subindex Total Return ( PGM), all offer investors exposure to platinum prices through derivatives contracts. These funds use platinum futures contracts to give investors exposure to the price of platinum. These existing platinum products, however, have faced challenges in open market trading. PTM and PTD are volatile funds that use leveraged strategies to track platinum. While PTM has a relatively high average daily trading volume of 85,000 shares, PTD has attracted virtually no investor interest.