And we welcome the effort to retain more low-cost units at Curry Village and Housekeeping. We also note, however, that some elements in the final preferred plan are less satisfactory. But, nonetheless, we see some problems in the plan that still need to be addressed in a satisfactory manner. We cannot agree with any change that would increase, rather than decrease, emissions and produce worse air quality or move impacts to new or expanded areas. The discussion in the EIS of air quality is conspicuously silent on the question of whether air quality standards would be met with this increase in NOx emissions.
Diesel fuels are also high in sulfur content.
Both sulfates and NOx are precursors of ozone. Exceedances of air quality standards for ozone have occurred in recent years in Yosemite Valley. Moreover, diesel fuel emissions contain deadly carcinogens as well as dangerous small particulates, and few diesel engines are operated with any serious emission control systems. Unlike cars, which have gotten cleaner, diesel busses have not. We continue to urge that busses bringing visitors into the valley need to use clean fuel technologies.