Particulate Matter: Not Just from the Tailpipe

Home>Particulate Matter: Not Just from the Tailpipe


In earlier blog articles we have talked about smog, emissions and ROI, and how the Lightning Hybrids ERS reduces exhaust emissions dramatically. In this article we’ll consider an unexpected source of automotive pollution: non-exhaust particulate matter. And – good news – we can help fleets reduce that also!

One of the major components of airborne pollution is particulate matter (PM). This consists of solid particles so small that they often remain airborne and can be inhaled, causing harm to the lungs and other systems in the body. In developing cities, such as Beijing and Delhi, PM emissions are probably the main contributor to pollution-related health issues, with lung damage in children and an increased incidence of early deaths in adults.

However, news stories such as the Volkswagen scandal, and the focus of emissions-related legislation such as Euro VI and EPA Phase 3, have placed the focus on engines and exhaust systems as the primary source of automotive PM. In reality, however, vehicles generate particulate matter from other sources, in particular from brakes, tires and road dust. And unlike engine-emitted PM, which is mostly carbon soot, materials from brakes can be additionally toxic, including heavy metals and organic compounds, and negatively affects air quality as well as water quality.brakes

It may surprise many to learn that for modern vehicles in well-regulated Western countries, non-exhaust PM emissions significantly outweigh what’s coming from the tailpipe. A recent study states, “Non-exhaust emissions already account for over 90% of PM10 and 85% of PM2.5 emissions from traffic.” This means that transitioning to alternative fossil fuels such as CNG or propane will have a relatively limited impact on PM.

So does the Lightning Hybrids Energy Recovery System (ERS) reduce PM? Absolutely, and in more ways than one.

The ERS operates by regenerating braking energy, which has the effect of substantially reducing the load on the engine when the vehicle accelerates. We’ve all seen “dirty” diesel vehicles emitting a belch of soot when accelerating. The ERS reduces or eliminates this black cloud because it provides the power for acceleration instead of the engine. For modern, regulated vehicles such as trucks with compliant particulate filters, this benefit can be limited as the tailpipe exhaust already has a very low PM content. But in areas where emissions regulations are non-existent (or not enforced), the ERS can make a huge difference to exhaust-borne PM.

But what about brake dust? The ERS reduces that also and here’s how: The ERS uses self-contained hydraulic components to capture, store and redeploy braking energy. “Capturing braking energy” actually means slowing the vehicle down in a way that doesn’t use the vehicle’s friction brakes. Using the friction brakes less translates directly into a large reduction in the rate of brake-related PM emissions. And there’s the added benefit of longer-lasting brake components.

The Lightning Hybrids Energy Recovery System has a long list of benefits; and for environmentally responsible fleets it’s valuable to know that its ability to reduce non-exhaust emissions is one of them.