Caterpillar’s team of global emissions experts has one big job: to understand what’s happening around the world (so the rest of us don’t have to). That makes them the ideal people to provide a high-level look at the emissions landscape — where things stand today, how far we’ve come and where we might be headed. We asked the team to answer some common questions about emissions standards. Read on for their insights.
For nonroad mobile machinery (wheeled and tracked equipment plus mobile gen sets), it was the mid-1990s. The U.S. and Europe led the way, establishing “tiers” or “stages.” Japan adopted comparable standards soon after. In the 2000s, other countries began to implement their own. Many jumped in around U.S. EPA Tier 3 levels and stayed there. Going further requires aftertreatment, which requires the use of ultra-low-sulfur diesel. Many countries don’t have that fuel available nationwide.
It differs by country, but generally speaking, nonroad emissions standards cover engines powering nonroad mobile machinery, emergency and non-emergency stationary units, rail applications and marine vessels. They aim to bring down emissions of oxides of nitrogen (NOx), hydrocarbons (HC), carbon monoxide (CO) and particulate matter (PM).
EU Stage V standards went into effect in January 2019, making Europe the world leader in stringency. The U.S., Canada, Japan and South Korea are at Tier 4 Final levels. The rest of the world is a mix. Looking at larger countries, Brazil, China, India and Turkey are all at levels comparable to Tier 3. Saudi Arabia is at a Tier 1 level. The majority of other countries are unregulated. Keep in mind this is a general overview — in some cases, different standards apply across different power categories or engine families.
Comparing Tier 1 to Tier 4 Final, there’s been a 96 percent drop in both NOx and PM. The levels we’re hitting today are very, very low. It’s often said that in terms of PM, the air coming out of a Tier 4 Final engine is cleaner than the air you breathe in some larger cities. Aftertreatment has reduced HC and CO emissions to virtually nothing. Now it’s all about reducing NOx even further — and that will depend on the development of new technology.
Here’s what we estimate right now:
If you’d asked that question a few years ago, we would have been fairly confident the answer was soon. That’s changed recently, though. China Nonroad Stage IV isn’t finalized yet, but we know it’s a hybrid of different standards from around the world. That may continue to drive unique products for the China market. EU Stage V is going after PM emissions, yet the noise we’re hearing from California indicates any future U.S. standards may focus more on NOx. It seems likely we’ll have more variety than alignment.
On the positive side, many countries — India, for example — soon will have ultra-low-sulfur diesel readily available nationwide. That will allow the use of aftertreatment systems and enable these countries to move to higher tier levels. Perhaps we’ll see more alignment in the future, although we may all be operating electric machines by then!
Big thanks to our global emissions team for sharing these basic facts with us. Clearly, emissions standards are complicated, and that’s why we have experts dedicated to the topic — and to working with you to understand what they mean for your business.
Whether you're looking for definitions of key terms, the status of current regulations or more details about aftertreatment solutions, here's where you'll find the latest updates from our emissions experts.