The Health Impacts of Diesel Pollution

Diesel-powered vehicles, vessels, locomotives, and equipment account for over 60% of all nitrogen oxides (NOx) and more than 70% of all fine particulate matter (PM2.5) emissions from US transportation sources. Heavy-duty diesel vehicles alone are responsible for 20% of all NOx and 25% of PM2.5 pollution emitted by vehicles in the country. That’s a lot of pollution!

The World Health Organization (WHO) classifies diesel exhaust as carcinogenic to humans. Ample research demonstrates that its components, which include PM2.5 and NOx (a ground-level ozone precursor), are harmful to human health even at low concentrations and through short-term exposures. So, what exactly are these pollutants, and how do they affect us?

Fine Particulate Pollution

Particulate matter, sometimes called soot, is created during the incomplete combustion of diesel fuel. Despite being just a fraction of the width of a human hair, particulate matter varies in size from coarse particulates (PM10) to fine particulates (PM2.5) to ultrafine particulates (less than 0.1 microns). Ultrafine particulates, which are small enough to penetrate lung cells, make up 80-95% of diesel soot pollution.

Particulate matter irritates the eyes, nose, throat, and lungs, contributing to respiratory and cardiovascular illnesses and even premature death. While everyone is susceptible, children, the elderly, and individuals with preexisting respiratory conditions are most vulnerable. Recent studies show that exposure to fine particulates is associated with higher rates of death from cardiovascular disease, lung cancer, and other fatal conditions, even at levels below current federal standards.

Communities of color and socioeconomically disadvantaged communities bear disproportionately higher exposures to PM2.5 pollution. Despite significant reductions in ambient concentrations over the past 40 years, these communities remain exposed to similarly higher levels.

IMPACTS FROM NITROGEN OXIDES (NOx)

Heavy-duty diesel vehicles emit significant levels of NOx, especially at lower speeds while driving through urban neighborhoods. NOx is both a pollutant and a precursor to fine particulate and ground-level ozone pollution. Exposure to NOx can lead to respiratory health issues, reduced lung function, and inflammation.

Long-term exposure to NOx has been linked to the development of asthma, while short-term exposure can trigger asthmatic symptoms. The impact of NOx on health is serious and requires immediate attention.

Ground-Level Ozone

Diesel emissions of NOx contribute to the formation of ground-level ozone, which irritates the respiratory system, causing coughing, choking, and reduced lung capacity. Ground-level ozone pollution, formed when NOx and hydrocarbons combine in the presence of sunlight, is hazardous for both healthy adults and individuals with respiratory problems. Urban ozone pollution has been linked to increased hospital admissions for respiratory issues such as asthma, even at levels below federal standards.

Vulnerable populations, including the elderly and those with preexisting conditions, are particularly harmed by ground-level ozone. Recent studies show a significant relationship between mortality among the Medicare population and short-term increases in ozone concentrations. Ground-level ozone also damages crops, leading to measurable reductions in agricultural output, a problem exacerbated by climate change.

The Rise of Electric Vehicles

Today, over 100 models of electric trucks and buses are on the market, including delivery vehicles, tractor trucks, shuttles, and charter buses. Businesses now have the option to purchase electric trucks and buses with significantly lower and more predictable fuel and maintenance costs. Electric trucks are ready for work now!

The availability of zero-emissions trucks continues to grow rapidly, and the difference between lifetime costs for electric and diesel trucks declines every year. The California Air Resources Board estimates that electric trucks will have a favorable total cost of ownership (TCO) by 2030, thanks to existing state policies and decreasing technology costs.

The Need for Public Policy

The landscape around electric trucks and buses has changed dramatically with recent technological developments. The last time the EPA considered heavy-duty truck emissions, electric vehicles were a future concept. Now, we can eliminate tailpipe emissions from heavy-duty vehicles entirely. However, the urgency of the climate crisis and health disparities in disproportionately impacted communities demands public policies to accelerate the national electric truck and bus market while providing regulatory certainty to the industry.