GAS MOWERS

sions from the oil and gas industry, the trucking industry and other high-polluting sectors, he noted. “And it makes sense to focus on another large category of emissions like the lawn and garden equipment.” e EPA in 2008 set ozone health limits of 75 parts per billion, then revised it further downward in 2015 to 70 parts per billion. State planners have said lawn and garden equipment contributes 2.5 parts per billion to that total on an average day. It may seem small, but compared to the other slices of the total that Colorado has the power to control, lawn and garden equipment is a tantalizing target.

Colorado’s ozone was trending downward for a while as cars got cleaner, coal- red power plants were retired and other rules took e ect. But in recent years, many metro area monitors are spiking into the 80s. en, just as the Air Quality Control Commission was about to nalize two EPA-required State Implementation Plans for both the 2008 and 2015 ozone standards, state regulators found they’d been calculating oil and gas contributions wrong. ey had underestimated how much ozone-causing emissions come from drilling operations, so