Air Quality: New Ozone Standard Designed to Protect Public Health

By Jay Baker

On October 1, 2015, the Environmental Protection Agency (EPA) set a new National Ambient Air Quality Standard (NAAQS) for ground-level ozone, lowering it from 75 to 70 parts per billion (ppb). The change was based on thousands of scientific studies that demonstrated the need for a lower standard to protect public health and the environment.

You may have several questions regarding ozone in general and the impacts of the new standard on Utah. I would like to answer a few of those questions here.

What is ozone?

Ozone is a gas composed of three oxygen atoms. It occurs naturally in the earth’s upper atmosphere and forms from chemical reactions near the earth’s surface. Ozone in the upper atmosphere is helpful because it protects us and the earth from the sun’s harmful ultraviolet rays. The ozone formed near the earth, called ground – level ozone, can harm our health.

Where does ground-level ozone come from?

Ground-level ozone is not directly emitted into the air. It is created through chemical reactions between volatile organic compounds (VOCs) and oxides of nitrogen (NOx) in the presence of sunlight. VOCs and NOx are emitted from things like paints and solvents, gasoline fumes, car exhaust, industrial boilers, refineries, and even trees and plants. Most ground-level ozone is formed on hot, sunny days in the urban areas of our state. But some parts of our state experience high ozone levels during the winter when snow is on the ground and temperatures are at or below freezing. Ozone can also travel long distances and cause high levels in areas that have very few emissions.

How does ozone affect us?

While ozone in the upper atmosphere protects us from ultraviolet rays, ground-level ozone can harm our health. Exposure to high levels of ozone can make it difficult to breathe and inflame the lining of the lungs. It can also worsen asthma, bronchitis, and other existing lung diseases. People who are most sensitive to the effects of ozone include children, older adults, people with lung disease, and those who are active outdoors. Ozone can also affect our environment, especially plants. Ozone absorbed by a plant’s leaves can reduce photosynthesis, damage leaves, and slow growth. It can also make sensitive plants more susceptible to insects, other diseases, and harsh weather.

What does establishing a new standard mean for us?

Now that EPA has issued a new standard, we have a year to evaluate our statewide air monitoring data to see which areas do and do not meet the new standard. Based on this monitoring data and other factors, the state will recommend to EPA which areas should be designated nonattainment, or not in compliance with the standard. EPA will evaluate the State’s recommendation and officially designate our attainment and nonattainment areas. Currently, our monitoring data indicates that the populated areas along the Wasatch Range from Brigham City down to Spanish Fork are not in compliance with the new standard in the summer months, and that the Uinta Basin is not in compliance during the winter months.

We have known that a more stringent ozone standard would present compliance challenges in several areas of the state and have taken proactive steps to reduce the ozone levels in those areas. However, once an area is designated as nonattainment, we are required to develop a State Implementation Plan (SIP) that details how we will attain the new standard as soon as possible. The SIP will propose actions and regulations to address ozone reduction at the sources that have the most impact.These plans will be developed in partnership with local government, industry, environmental groups, the public, and other key stakeholders.

How can I help reduce ozone and clean our air?

We will develop the SIP to reduce ground-level ozone in Utah over the next five years. While we work on the plan, there are several things that all of us can do right now to reduce the pollution that causes ozone. I plan to walk and ride my bike more and use my car less. I also plan to gas up during the cooler parts of the day so the VOCs (gasoline fumes) are less likely to react and form ozone. Anytime I use paint, indoors or outdoors, I can use low- or zero-VOC paint.

To learn more about the new standard, check out EPA’s overview fact sheet. Additional fact sheets available from the EPA include ozone and health, ozone and children’s health, ozone basics, and ozone by the numbers. For ideas on what you can do to reduce ozone and make our air healthier, please visit the ozone page on the DEQ website.
Jay Baker

I am an environmental scientist in the Department of Environmental Quality, where I am responsible for planning to meet ozone and regional haze regulations.