What happened
US environmental regulators now require three California counties to collect detailed air pollution data from smaller sources. This means local officials will have a clearer picture of all emissions, not just those from big industrial sites.
Why it matters
For years, air quality enforcement focused on large, obvious polluters. This change means regulators will now track emissions from many smaller sources, like dry cleaners or gas stations, that add up to significant pollution. This shift makes it harder for local officials to ignore cumulative pollution from distributed sources, which often disproportionately affects poorer communities.