First, there was the announcement earlier this week that Metro had received a $10.5-million grant for 30 near-zero emission buses to replace old stinky diesel buses on contracted lines in the South Bay and Gateway Cities. That was Tuesday.

And now more news along those lines: Metro will install near-zero emission natural gas-powered engines in 125 buses with a $1.875-million grant from the Mobile Source Air Pollution Reduction Committee (MSRC), the agency announced today.

The engines by Cummins Westport have emissions of Nitrogen Oxides (NOX) and particulate matters that are 90 percent lower than current federal standards for heavy-duty engines, according to the state of California.  

The new engines will be installed in buses that Metro already operates and will help extend the lifespan of the vehicles, which each travel about 45,000 miles annually on area roads. These 45-foot buses are already powered by compressed natural gas — a fuel that produces far fewer emissions than diesel buses formerly used by Metro — and the new engines will make these buses even cleaner.

The engines will be installed between July 2017 and July 2018 with all the buses in operation by August 1, 2018.

NOX is produced when fuel is burned at high temperatures. It is a major contributor to smog and ozone levels in Southern California that have been lowered in recent years but continue to exceed federal standards. Particulate matter consists of tiny particles and liquid droplets that when inhaled can get stuck in the lungs and cause serious health problems.

There were nearly 306 million boardings on Metro’s 2,200-plus bus fleet in the past year. Metro’s bus fleet is the second busiest in the United States behind only the New York MTA.

In other Metro Bus news this week, the agency announced that it has received its 900th and final New Flyer bus on the current order from that firm and the Metro Board approved a motion asking Metro to draw up plans for using electric-only buses on the Orange Line.