I recently traveled to Los Angeles on business, and it got me thinking about emissions. Being raised in a suburb of Indianapolis and then living in Columbus, Indiana, most of my life, I took for granted blue skies and clean air. It wasn’t until the 2010 timeframe when I frequently traveled to China where I developed a different perspective. After several trips to China, I realized that the smog and air quality affected me. My eyes started to hurt; I developed a scratchy throat, had inflammation, and a lot of congestion.
I never gave it much thought and just assumed it was a “China problem.” One time, however, I flew into Los Angelos International airport to catch a connecting flight back home. As I landed, I noticed there was considerable amount of haze and smog hovering over the city. It looked worse in LA than it did in Beijing. (Air quality does vary from day to day so some days are better than others.) I then realized that this is in our own back yard and unfortunately for tens or hundreds of millions of Americans it is in their own yard — literally.
These experiences helped me develop my mission for the latter part of my career: to help the industry transition to powertrain solutions that are clean, reliable and low cost. I was fortunate to join the NACFE team whose mission is helping the industry with new technologies, decarbonization, and finding the right solution for fleets’ specific needs.
As we think of the Messy Middle and all the different solutions, it is worth spending a little time discussing “emissions.” This word is used rather loosely. More specifically, there are two general categories of emissions — criteria pollutants and greenhouse gases (GHG). The two are very different; their impact on humans and the environment are different, and the solutions to reduce them are different. One way to think of this is that criteria pollutants harm human beings and our ecosystem while GHG harm the environment.
Thick layer of smog and haze from nearby brush fire obscuring the view of downtown Los Angeles buildings in Southern California. Shot from hilltop in popular Griffith Park.
What are pollutants?
Two types of criteria pollutants are nitrogen oxides (NOx) and particulate matter (PM).
Criteria pollutants adversely affect air quality and have an impact on health. NOX and PM have been found to contribute to respiratory issues and heart disease. They create environmental problems such as smog and acid rain. Finally, they are typically concentrated in localized areas such as cities.
NOX is produced through combustion. While we in the commercial vehicle industry think of NOx being produced by engines, it is also important to realize that it is also produced by electricity plants, assuming the power plant is not solar/wind/hydro/nuclear. (e.g. the power plant uses a combustion process to generate electricity). Therefore, when evaluating battery electric vehicles, you need to think about the source of the electricity.
Particulate matter is a mixture of many things, ranging from small solids to aerosols. The shape, size, and chemical and material make-up can vary. If the particles are less than 10 microns they can be inhaled into the lungs.
Greenhouse gasses
Greenhouse gases include carbon dioxide (CO2), methane (CH4), and nitrous oxide (N20). According to the EPA, CO2 is estimated to contribute to about 80% of the GHG emissions. Methane comes from landfills and oil and natural gas production. Nitrous Oxide is emitted from nitrogen fertilizers. When these gases are emitted, they trap heat in the atmosphere and contribute to global warming. Their impact is at a global level and not a local one like criteria pollutants.
Burning fossil fuels emits CO2. There is a nice relationship between the environment and economics for a fleet when it comes to CO2. As the engine and vehicle become more efficient, less fuel is burned and therefore less CO2 is emitted so you get a win-win for a combustion-based vehicle.
In addition to the EPA regulating CO2 via GHG Phase 1-3 standards and CARB establishing zero-emission mandates, there also are global efforts to reduce GHG and CO2. An example is the Paris Accord, which is aimed at combatting climate change by preventing temperatures from rising more than 1.5°C. Furthermore, other countries and municipalities throughout the world have established targets to reduce GHG.
Solutions for emissions
Battery electric and fuel cell vehicles emit zero criteria pollutants and greenhouse gases. However, you should not conclude there are no adverse environmental impacts, and we need to think about these products from “well to wheels.” More specifically, we need to think about how the electricity or hydrogen is produced. Unless the energy is green (e.g. solar, wind, or hydro) or nuclear, fossil fuels were used to make the energy, therefore NOx, PM, and greenhouse gases were produced.
For internal combustion engines, the approach to reducing NOx and PM is very different from that of greenhouse gases. Techniques covered in this article discuss how NOx will be reduced for 2027 engines.
As for reduction of GHG in internal combustion engines, one general rule of thumb is that there is a direct correlation between reducing fuel consumption and greenhouse gases. This can be done by creating vehicles and trailers with better aerodynamics or using more fuel-efficient tires to improving the efficiency of the engine and powertrain. Check-out NACFE’s SuperTruck II report which goes into some of this. Hybrids are also a way to reduce fuel consumption by recapturing energy during braking and decelerations. A hydrogen engine also is a potential solution to reduce GHG. However, like the BEV, you must consider how the hydrogen was produced.
The Messy Middle is complex. We are trying to achieve many environmental goals by reducing “emissions.” And as is true so often in life, there is no one perfect solution which satisfies all the objectives. This makes it interesting for those of us who want to bring solutions.
