Today, the U.S. Environmental Protection Agency (EPA) proposed to strengthen the National Ambient Air Quality Standards (NAAQS) for ground-level ozone, based on what EPA claims is extensive scientific evidence about ozone’s effects on public health and welfare. With this announcement, business just got a whole lot tougher, if not impossible for California. EPA is proposing to update both the primary ozone standard, to protect public health, and the secondary standard, to protect the public welfare. Both standards would be 8-hour standards set within a range of 65 to 70 parts per billion (ppb). EPA is also seeking comment on potentially setting the levels for the health standard as low as 60 ppb! To put this in perspective, in the 1990’s the Central California Ozone Studies measured background ozone levels on the Farallon Islands off the California Coast of 60 ppb! The San Joaquin Valley Air Pollution Control District has made the comment that it would take the elimination of every car, truck, tractor and cow and it would still be unable to achieve this standard. Ozone forms in the atmosphere when emissions of nitrogen oxides and volatile organic compounds “cook” in the sun. Emissions from sources such as cars, trucks, buses, industries, power plants, and products such as solvents and paints are among the major man-made sources of ozone-forming emissions. As required by the Clean Air Act, EPA would make attainment/nonattainment designations for any revised standards by October 2017; those designations likely would be based on 2014-2016 air quality data. A number of California counties likely would have attainment dates ranging from 2032 to late 2037. EPA analyzed the benefits and costs for California separately, because a number of areas in California would have longer to meet the proposed standards. Estimated costs in California post-2025 are $800 million for a standard of 70 ppb and $1.6 billion for a standard of 65 ppb.