California has long been at the forefront of environmental policy, particularly when it comes to reducing emissions from vehicles. As a recognized leader, the California Air Resources Board (CARB) has pioneered numerous programs aimed at curbing pollution from mobile sources. It’s a critical mission, considering that mobile sources are the biggest culprits behind criteria pollutants and greenhouse gases (GHG) in the state. They contribute approximately 80% of ozone precursor emissions and about half of California’s total GHG emissions, factoring in the entire lifecycle of transportation fuel.
Two pollutants are especially concerning in California: ozone (smog) and fine particulate matter (PM2.5, or soot). The National Ambient Air Quality Standards (NAAQS) for these are frequently challenged in the state, which unfortunately experiences some of the worst air quality in the nation. The South Coast and San Joaquin Valley air basins hold the unenviable distinction of being the only regions in the US classified as ‘Extreme’ nonattainment areas for the federal ozone standard of 70 parts per billion (ppb). These regions also grapple with alarmingly high levels of PM2.5 pollution.
The Advanced Clean Cars II regulations are a cornerstone of California’s comprehensive strategy to tackle these urgent public health crises, while adhering to both state and federal environmental laws. Emissions from vehicle engines have far-reaching negative consequences for public health, the environment, and the climate, in a complex web of interconnected impacts. Reducing one type of emission often helps in reducing others, amplifying the positive effect. For instance, as the climate warms, controlling ozone becomes increasingly difficult, and wildfires release more particulate matter, further degrading air quality. By aggressively reducing emissions that drive climate change, California is also indirectly bolstering its efforts to control ozone. This is because the pollutants primarily responsible for ozone formation – nitrogen oxides (NOx) and hydrocarbons (HC) from fuel combustion – are also significant contributors to climate change. These crucial emission reductions will not only help stabilize the climate but also lessen the risk of severe droughts and wildfires, and consequently, the hazardous fine particulate matter pollution they generate. California’s commitment to a clean car program is therefore a multifaceted approach to safeguard public health and the environment.
