Someone told me this week that Tier 4 is here. The more stringent emissions standard for off-road vehicles (including, importantly, construction equipment) begins phasing in this year and is fully in place by 2011. According to Cummins, a big producer of the engines, Tier 4 "represents a 90 percent reduction in particulate matter (PM), and a 50 percent reduction in emissions of Nitrogen Oxide (NOx)" over the current Tier 3 standard. Tier 4 also begins to address sulfur content in diesel.The phase in period allows industry time to incorporate: replacing equipment at the end of its service life, or developing the experience and training to maintain the new engines. A noisy, messy corner of the motive world will become significantly quieter and cleaner in the next four years.
