The pitch for the EPA's Thursday proposal is a number with a dollar sign. Weakening the heavy-duty truck emissions rules will, in the telling of its supporters, 'ease real burdens for operators,' in Administrator Lee Zeldin's words, and 'alleviate burdensome diesel regulations on behalf of farmers, truckers, and small business owners' [1]. Right-leaning outlets rounded it to a headline: save truckers 12 billion dollars [2].
There is a second number, and the EPA supplied it. In its own analysis of the proposal, the agency projects that the change will produce 'a 4.2% increase in nitrogen oxide pollution by 2030' and an '11.6% increase by 2055' [1]. Nitrogen oxide is the precursor to smog. The agency proposing to raise it printed the figure, and then, by NPR's account of the proposal documents, 'did not model resulting air quality or human health effects' [1].
Data
| By 2030 | 4.2% increase |
|---|---|
| By 2055 | 11.6% increase |
What the proposal changes is concrete. It scales back and postpones the emissions-technology warranty and useful-life provisions, and it replaces 'limp mode' - the automatic reduction in engine power when the emissions system malfunctions - with driver alerts instead [1]. The savings estimate is real too: 4,130 to 6,152 dollars per diesel engine, by EPA's own reckoning [1]. That is the ledger's credit side, and it is not in dispute.
The debit side is where the modeling stops. Heavy trucks are about 5 percent of the vehicles on the road and the single largest source of the pollutants the Environmental Defense Fund links to asthma, bronchitis, heart attacks and strokes [1]. An agency that projects a 4.2 percent rise in exactly those pollutants, and then declines to estimate the health consequences, has left the most important column blank on purpose. A dollar figure sits on one side of the scale; on the other, where the count of aggravated asthma or additional cardiac events would go, there is a projection of more pollution and no projection of who breathes it.
This is a proposal, not a final rule, and a public comment period lies ahead [1]. The comment that the record most needs is the one the agency did not write: having forecast the pollution increase, it owes the arithmetic that turns 4.2 percent into people.
