“If consumers lose confidence in diesel cars, this will have a substantial impact on future platinum demand,” Georgette Boele, a precious metals strategist at ABN Amro, told the WSJ.

The ETFS Physical Platinum Shares (NYSEArca: PPLT) was down 0.7% Wednesday, briefly touching its 52-week low. PPLT fell 2.8% over the past week and 8.4% in the last month.

However, palladium, a major component in gasoline engines, could capitalize on the waning confidence in diesel engines.

ETFS Physical Palladium Shares

For more information on the palladium market, visit our palladium category.

Max Chen contributed to this article.