Many communities across the United States face serious challenges related to air quality and respiratory health. Emissions from diesel engines have been linked to the worsening of respiratory conditions, particularly in populated areas near roadways where residents experience higher rates of asthma, cardiovascular diseases and other health issues. In Delaware, transportation is a major contributor to pollution, producing 75% of the state’s nitrogen oxide, or NOx, emissions, which contribute to the formation of ground-level ozone.

Nationally, in 2022, diesel fuel accounted for nearly one-quarter of all energy consumed by the U.S. transportation sector. According to the U.S. Energy Information Administration, about 25% of the country’s carbon dioxide, or CO₂, emissions were also tied to transportation, much of it from diesel use.

Why is this notable? Diesel engines tend to emit more NOx and particulate matter, or PM, than regular gas-powered engines. While federal and state regulations have significantly improved the cleanliness of today’s diesel engines compared to those produced in previous decades, many older engines remain operational, resulting in harmful emissions on our roadways that can lead to respiratory issues.

The government plays a crucial role in addressing air quality and public health challenges. In 2005, Congress passed the Diesel Emissions Reduction Act, a bipartisan effort co-authored by Sen. Tom Carper of Delaware. This program supports businesses, nonprofits and local governments in replacing or retrofitting older medium- and heavy-duty diesel vehicles. A key goal of the act is to reduce emissions of NOx and PM, both of which contribute to respiratory and cardiovascular health issues.

Since the Diesel Emissions Reduction Act Program began in Delaware in 2008, the state has received multiple grants from the Environmental Protection Agency to support the replacement and retrofitting of older diesel vehicles. For example, in 2017, Delaware was awarded a $224,165 Diesel Emissions Reduction Act grant to replace school buses serving children across the state.

In addition to Diesel Emissions Reduction Act funding, Delaware benefited from a 2017 settlement agreement with Volkswagen related to diesel emissions violations. The state received $9.6 million from this settlement, administered by the Delaware Department of Natural Resources and Environmental Control (DNREC) through the Environmental Mitigation Trust.

Delaware has allocated 15% of these funds, approximately $1.4 million, to expand the state’s electric vehicle fast-charging network, while the remaining 85% has been used to support companies and school districts in mitigating diesel emissions through vehicle replacements and retrofits.

To supplement funding from the Diesel Emissions Reduction Act and VW settlement, participating partners have invested nearly $28.7 million to tackle pollution from vehicles traversing Delaware’s streets. That funding helps lowers emission — particularly NOx — providing benefits both to the environment and to public health.

Diesel engines also contribute to greenhouse gases, which harm the environment and play a part in climate change.

“Participants in this program have the option to replace either just an engine or an entire vehicle,” said Deanna Morozowich, program manager with the DNREC Division of Air Quality. “Most who take part opt to simply replace the vehicle, in part because swapping out an engine necessitates additional costs in terms of time and labor.”

Since 2018, the state has facilitated the replacement of 155 diesel school buses with those powered by cleaner technology, including improved diesel vehicles and vehicles powered by alternative fuels. Approximately one-third of these projects received funding through the Diesel Emissions Reduction Act Program, while the remainder benefited from financial support from the Environmental Mitigation Trust.

Among the participants is Sutton Bus and Truck Company, which operates 70 school buses. The company replaced four diesel buses in 2016 and four diesel buses in 2019 using Diesel Emissions Reduction Act funding. In 2021, it leveraged funds from the Environmental Mitigation Trust to replace eight more buses.

“It was beneficial to our company but also beneficial to our community. To have incentives to replace existing diesel equipment with new, reliable efficient equipment is monumental,” President Dave Sutton said. “It not only improved our company footprint but also improved the overall air quality to the passengers we transport every day. The financial savings thoroughly outweighed the efforts required to complete our project.”

Sutton said his company hopes to participate again in the future when it has buses that need to be replaced.

DNREC collaborates with the Delaware Department of Education and local school districts to identify vehicles nearing the end of their operational lives and to notify contractors (who own the majority of buses used for public school transportation in Delaware) about funding opportunities. The funding provided by these programs is beneficial because margins can be small in an industry where the per-student rebate is set every year by the government, meaning opportunities for cost-savings for these businesses are often vital.

“The Diesel Emissions Reduction Act funds helped the Department of Education be able to purchase more annual replacements than normally scheduled, as well as offsetting any additional costs associated with the difference in purchase price for a diesel engine to a propane engine. These initiatives have helped our communities by enabling the district operations to clear their spare fleets of older non-clean diesel school buses and transition newer route buses in those roles while placing the newest cleanest buses on their daily route buses,” said Tyler Bryan, who manages school transportation for the Delaware Department of Education.

Replacing diesel vehicles is not limited to schools; this program also facilitates the replacement of diesel-powered dump trucks, garbage trucks, forklifts, excavators, engines used at the Port of Wilmington and Amtrak transfer table engines. Other eligible vehicles include heavy-duty farm equipment and box trucks — essentially, any vehicle that operates on diesel fuel.

Marcus Stevens, owner of Evergreen Waste Services, had glowing reviews of his partnership with DNREC to reduce emissions. Stevens became interested in an electric garbage truck after seeing one at an expo in 2021, and when he learned a few months later the government would help cover some of the cost, he resolved to apply.

Stevens put together a proposal requesting $3 million to purchase five zero-emission trucks and was awarded $1.5 million from the Environmental Mitigation Trust. That funding, he said, was essential to offsetting the cost, as a typical trash truck is around $350,000 to $400,000, whereas the electric ones he was interested in cost $685,000 apiece. With an extra $300,000 per truck essentially bringing the cost of the electric vehicles down to the price of a regular diesel-powered truck, he could afford five.

Working with DNREC was straightforward, and Department personnel were eager to help, Stevens said. He noted some people might be hesitant to partner with the government for one reason or another but said he would recommend this initiative to anyone.

He’s excited about the impact the electric garbage trucks can have in terms of not just environmental pollution but also noise pollution, as the electric vehicles are quieter than typical waste haulers.

“A lot of times with garbage, people aren’t forward-looking, but I think this is actually a really good piece of innovation, so I wanted to be part of that,” Stevens recalled.

His company is small, focusing only on northern New Castle County, meaning the financial support provided by DNREC was necessary for this project.

Like all participants, Stevens has complied with the requirement to destroy old vehicles as stipulated in the funding agreement.

The amount of funding available through the program varies annually based on congressional allocations, though DNREC generally has more funding available than demand. Additionally, extra dollars may occasionally be accessible as a “bonus” if the state can provide a matching contribution, which has been made possible through the Environmental Mitigation Trust.

The exact cost-sharing depends on the vehicle or equipment being replaced: The program covers 25% of the cost for traditionally fueled school buses and 45% of the cost if the owner is transitioning to electric-powered vehicles. Detailed guidance on eligible uses of the funding, including federal and mandatory cost shares that must be provided by the project partner, can be found on EPA’s website.

While the vehicles replaced so far represent a portion of the tens of thousands of vehicles operating on our state’s roadways daily, the impact of a single vehicle can be striking. For example, the replacement of a 2009 model year school bus with a cleaner diesel alternative in 2024 resulted in a 74% decrease in NOx, a 59% reduction in PM, a 90% cut in hydrocarbons, or HC, and a 43% decline in carbon monoxide, or CO, emissions for that individual vehicle.

Similarly, the replacement of a 2000 model year dump truck with a cleaner 2023 diesel model yielded reductions of approximately 99% across all five categories (NOx, PM, HC, CO, CO₂). In other words, the new truck put out just 1% of the pollutants produced by the former model — a significant improvement.

Over the long term, reduction in pollution can add up. EPA estimated a 2017 replacement of nine school buses in Delaware would result in 57 fewer tons of NOx, 7 fewer tons of PM, 9 fewer tons of HC and 12 fewer tons of CO in the atmosphere by the end of their lifespans.

Understanding how these benefits scale with the replacement of additional vehicles is crucial, particularly concerning school transportation. Children are more susceptible to air pollution, and some students spend at least an hour on the bus every single school day. One of the most common childhood diseases in the United States is asthma, a condition which affects more than 5 million youngsters and is thought to be tied to air pollution along with other health problems.

“In the grand scheme, I think it’s very important that we have some of these vehicle replacements, especially if we’re going from diesel to electric. Reducing our footprint matters,” Morozowich said.

According to a 2022 report, from 2008 to 2018, EPA funded the replacement of around 74,000 engines or vehicles nationally, decreasing emissions by millions of tons. This initiative carries significant health benefits adding up to $8 billion, as well as 850 fewer premature deaths, per the agency.

It’s clear that reducing diesel emissions is a win-win for all, from private companies concerned about their environmental footprint to governments intent on protecting public health.

For more information on reducing diesel emissions and how your business can obtain funding from DNREC to do so, visit dnrec.delaware.gov/air/mobile-sources/diesel-emissions.

Related Topics:  air quality, diesel, emissions, health, outdoor delaware, science, transportation