Audit, Compliance and Risk Blog

EPA Proposes Stricter Standards For Ground Level Ozone in Ambient Air

Posted by Jon Elliott on Mon, Jan 19, 2015 Clean Air Act (CAA) requires the Environmental Protection Agency (EPA) to create a list of air pollutants based on emissions that cause or contribute to air pollution that may reasonably be anticipated to endanger public health or welfare.  EPA also sets air quality criteria for acceptable concentrations in ambient air, referred to as National Ambient Air Quality Standards (NAAQS).

Ground level ozone is one of these “criteria air pollutants.” On December 17 EPA published a proposal to tighten the existing NAAQS of 75 parts per billion (ppb) as an 8-hour average, to a range between 65 and 70 ppb.  The proposal notes that the Clean Air Scientific Advisory Committee (CASAC; an independent scientific advisory committee established by CAA to provide advice to EPA) had identified scientific support for a regulatory level as low as 60 ppb, and solicits comments on levels from 60-75 ppb. Readers should note that California has already set a state ambient air quality standard of 70 ppb.

EPA justifies the proposed change on scientific evidence accumulating since the agency adopted the existing NAAQS in 2008. The agency estimates that the tighter standard will provide significantly better protection for children, preventing 320,000 to 960,000 asthma attacks and 330,000 to 1 million missed school days. It also estimates that the tighter standard prevent 710 to 4,300 premature deaths; 1,400 to 4,300 asthma-related emergency room visits; and 65,000 to 180,000 missed workdays.

Ground level ozone is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of sunlight.  Major sources of NOx and VOCs emissions include industrial facilities and electric utilities, motor vehicle exhaust, gasoline vapors, and chemical solvents. Controls focus on changes in the designs, formulations and techniques, in order to reduce emissions of NOx and VOCs.  EPA’s proposal finds that ongoing technological and regulatory enhancements since 2008 will help states meet the new standard.  These include major regulations directed at power plants and other major stationary sources, including EPA’s Mercury and Air Toxics Standards (MATS), and Cross-State Air Pollution Rule (CSAPR; also referred to as the Transport Rule).  They also include clean vehicle and fuels standards designed to reduce emissions from mobile sources.

What Can We Expect From EPA and States?

Once EPA finalizes changes – which it intends to do by October 1, 2015 –states will have time to tighten source-specific rules in order to reduce emissions from stationary and mobile sources enough to attain the new NAAQS. Depending on the severity of their ozone problem, areas would have between 2020 and 2037 to meet the new federal standard.  States will revise their state implementation plans (SIPs) and associated rules and regulations to establish additional controls on NOx and VOC emissions. Many can be expected to be enhancements of existing types of controls, including those affecting:

  • Combustion at power plants and industrial facilities.

  • Thermal processes at industrial facilities.

  • Engine designs.

  • Fossil fuel compounding (gasoline, etc.).

  • Manufacturing and use of coatings and finishings that contain VOCs.

Where Can I Go For More Information?

Specialty Technical Publishers (STP) provides a variety of single-law and multi-law services, intended to facilitate clients’ understanding of and compliance with requirements. These include:

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About the Author Elliott is President of Touchstone Environmental and has been a major contributor to STP’s product range for over 25 years. He was involved in developing 16 existing products, including Environmental Compliance: A Simplified National Guide and The Complete Guide to Environmental Law.

Mr. Elliott has a diverse educational background. In addition to his Juris Doctor (University of California, Boalt Hall School of Law, 1981), he holds a Master of Public Policy (Goldman School of Public Policy [GSPP], UC Berkeley, 1980), and a Bachelor of Science in Mechanical Engineering (Princeton University, 1977).

Mr. Elliott is active in professional and community organizations. In addition, he is a past chairman of the Board of Directors of the GSPP Alumni Association, and past member of the Executive Committee of the State Bar of California's Environmental Law Section (including past chair of its Legislative Committee).

You may contact Mr. Elliott directly at:

photo credit: Dylan Passmore via photopin cc

Tags: Environmental risks, Environmental, EPA, Greenhouse Gas, ghg, climate change