[Big Dave]

Almost all the diesel sold in the US now is ultra-low sulfur diesel (ULSD) mandated to <25 ppm sulfur vs the 5,000 ppm sulfur stuff your father's Detroit 6-71 ran on.

According to the EPA's 2004 reoport to Congress, ambient concentrations of pollutants is now the lowest it has been in living memory. Sulfur dioxide is down 60% from 1970 levels. Lead has nearly disappeared. Particulates are down by over 50%.

I will trade on the very clean environment for public health purposes and concentrate on MPG.

Strange you mention asthma. After 1980, SO2 ambient concentrations declined but asthma cases have increased by the same margin. Maybe a whiff of SO2 has a therapeutic effect.