Diesels from the 1970s, '80s, and even into the 1990s earned a reputation for being smoky, foul-smelling, but efficient powerplants. Scientific studies warned of the respiratory hazards of particulates and the effect of nitrogen oxides on smog, and regulations limiting the amount of allowable NOx and particulates soon followed.
An infographic from commercial vehicle and equipment news site EquipmentWorld.com created a graphic based on data from Dieselnet.com. Beginning in 1996, when the first standards were implemented for diesel emissions (prior to which, diesel emissions were totally unregulated and unchecked), the maximum allowable NOx quantity was 9.2 grams per brake horsepower hour. That was cut to 6 g/bhh in 2004, further to 4 g/bhh in 2006, and now to just 2 g/bhh as of 2011. Full implementation of Tier 4 emissions standards allow for a mere 0.4 g/bhh of NOx, and just 0.02 g/bhh of particulates, the same as the 2011 standards.
To further show the reductions in emissions, it said that current diesel Class 8 trucks run so cleanly that a fully-loaded 18-wheeler driving from Chicago to Baltimore emits no more pollution than grilling hamburgers for a family of four.
Perhaps most impactful and dramatic is the graphic showing that it would take a fleet of 60 new clean diesel trucks to equal the emissions of one truck from 1988. Toward the end, estimated emissions savings from Tier 4-compliant trucks are compared to 1.445 million polar bears or over 10 million EPA administrators. Probably not the most scientifically accepted yardsticks of emissions reductions, but sure, why not?
Sure, having to fill up that DEF tank every few thousand miles, and the regen cycle on the particulate trap may be inconveniences, but cleaner air is something everyone can appreciate.
Source: Equipment World