Shifting Freight Demand From Truck To Rail Will Improve Air Quality, Study Finds

Unlike human-caused climate change, which has been subject to intensely polarized perspectives, studies have been very conclusive on the effect of air pollution on human mortality rates. The World Health Organization (WHO) estimates that 4.2 million people die annually as a result of exposure to outdoor air pollution and has flagged diesel emissions from freight transportation activities to be a key threat to public health. 

A new study conducted by Cornell University has shed light on the impact of adverse air quality on public health based on projected freight-related emissions in the year 2050. The study has considered three emission scenarios for its research: (1) the economy grows as expected and stringent emission controls exist; (2) the existence of a carbon pricing climate policy that charges fleets based on their emissions; and (3) a world where futuristic trucks have drastically low emissions footprint. 

The study found that if the economy is shepherded by stringent emission control regulations and has no external stimulus, it would still see a widespread reduction of particulate matter in 2050 compared to its 2011 levels. However, if a carbon tax based on truck emissions is added to the mix, the conditions will improve to positively impact health conditions by roughly 9%.  

The ideal scenario would be a world driven by green technology that is both economically and functionally on par with the current conventional trucks, which can help realize substantial health benefits of around 20%. 

That said, the world has come a long way from its pre-1990 truck models. Current truck models have 98% lower particulate matter and NOx emissions. The Cornell study believes that removing super-emitter trucks from the picture can further the cause of reducing air pollution. Super-emitters are trucks that are at the edge of their existence and are so old that no amount of maintenance can get them back to acceptable working levels. 

Such super-emitters are notorious for emissions, with studies showing that their particulate matter emissions might be up to 70 times higher when compared to a normal truck. Cornell's study cites research that estimates a 30% reduction in long-haul freight emissions by 2050 if the super-emitters are eliminated. 

Nonetheless, while regulations and carbon taxes could help the government maintain a tight leash on road freight emissions, there might be unintended consequences arising from the other modes. With constant pressure and a potential rise in truck hauling costs, there might be a shift towards railroads. Though freight moving by railroads tends to have lower emissions than when they move on a truck, the age of the railway equipment in 2050 will need scrutiny. 

"In the U.S., a majority of long-haul trucks have a lifespan of four to 15 years. By 2050, almost all older and dirtier trucks built before the 2010 standard are projected to be retired. Locomotives have a longer lifetime than trucks, and by 2050 most of the rail fleet will be built under Tier 4 emission standards," said the study. "The truck sector has a 35% decrease in particulate matter emissions, while the rail sector sees a 25% increase."

Then again, as the absolute level of particulate matter emissions from a truck is considerably higher than from a locomotive on a pound-per-pound basis, a regulatory push towards moving freight via the railroad will need to be considered by the government.

The study advocates for stringent emission control measures that can translate into saving 3,600 people from dying prematurely every year and lead to $38 billion in healthcare savings. Overall, a climate policy that helps shift freight demand from trucks to railroads will generate greater health benefits. However, certain regional pockets that feature a highly dense railroad network will have their air quality moderately compromised due to increased rail activity.

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