EPA Emission Standards

Heavy-duty trucks and buses in North America have been equipped with advanced emission technologies since the introduction of EPA 2007 standards. Since then, new EPA phases—up to EPA 2021—have further tightened regulations, transforming exhaust systems into sophisticated emissions control units. Today's systems rely on a combination of filters, catalysts, sensors, and DEF (Diesel Exhaust Fluid) systems to significantly reduce harmful pollutants.

When operating properly, the exhaust from an EPA 21-compliant vehicle can be cleaner than the surrounding air in many urban environments. However, keeping the system functioning at peak performance requires regular maintenance. Many costly breakdowns can be prevented with simple service routines, and early signs of trouble—often visible in exhaust behavior—can point to underlying engine issues before they escalate.

At Dinex, we offer a complete range of high-quality aftermarket parts to support all components of EPA 10, 13, 17, and 21 emission systems. More than just a parts supplier, we empower our customers with technical training, expert knowledge, and troubleshooting support—because we understand the complexity of keeping today’s advanced emissions systems operating at their best.

EPA 2004 regulations were the last set of standards that heavy-duty trucks could meet through engine optimization alone. With the introduction of EPA 2007, Diesel Particulate Filters (DPFs) became necessary to capture fine particulate matter (PM), and by EPA 2010, most OEMs adopted Selective Catalytic Reduction (SCR) systems to meet strict new NOx limits.

Since then, the cost and complexity of emission systems have grown significantly—but the environmental impact has been extraordinary:

Toxic nitrogen oxides (NOx) have been reduced by over 95%, and particulate emissions by more than 99% compared to levels from 30 years ago. In fact, under normal conditions, the exhaust from a modern heavy-duty truck can be cleaner than the air in many urban environments.

While current EPA emission systems are incredibly effective, the journey toward cleaner mobility isn’t over.

Coming in 2027, the new EPA standards will push the industry even further—targeting near-zero emissions across all driving conditions, tightening control over regulated pollutants, and capturing ultrafine particles as small as 10 nanometers (about 10 times smaller than a flu virus).

Dinex is already working closely with leading global OEMs to develop the next generation of emission technologies—so we’ll be ready when the future arrives.

Read more about our innovations here: