There's been a massive improvement in air quality and public health.
California has some of the most comprehensive air pollution prevention measures in the US and a new report from the University of California, Berkeley, shows that the state’s policies have been highly effective at improving air quality and public health.
Researchers looked at diesel particulate emissions from 1990 to 2014 as an indicator of relative air pollution levels in California and the rest of the country. The 24 year period saw a 78 percent diesel particulate reduction in California compared to 51 percent in the country as a whole. Deaths from heart and lung disease linked to diesel pollution also fell by 82 percent statewide.
Over the past three decades, the state has not just tightened regulations on diesel engines, but also initiated the transition to electric ships, started building the west coast electric highway, and transitioned to a lower-sulfur form of diesel fuel which emits less fine particulate matter than standard diesel. California continues to progress on its air quality journey, especially as the state is set to discontinue the sale of new combustion engine vehicles by 2035.
Despite this progress, the report does note that California still has room for improvement. They emphasize that the agricultural industry has struggled to lower emissions even though they account for 18 percent of the state’s diesel pollution.