CARB Says EPA Could Impose Tighter Auto PM Limit Than State Rules

California air officials and others say that several factors -- including differing geographic considerations and regulatory baselines -- could spur EPA to weigh requirements stricter than the state’s current particulate matter (PM) standards in its upcoming multi-pollutant vehicle standards, in line with calls from health advocates. EPA’s precise plans on the issue are unclear amid a mounting focus on vehicle electrification as a key strategy to cut greenhouse gases and criteria pollution, though EPA has also pledged to continue a...