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What you need to know about Ozone Action Days

Air quality meter and health measurement scale from excellent to bad outline diagram. Urban smoke and emission pollution index as indicator for contamination and particles in air vector illustration.
Planet Detroit
Air quality meter and health measurement scale from excellent to bad outline diagram. Urban smoke and emission pollution index as indicator for contamination and particles in air vector illustration.

Ground-level ozone is created when urban landscapes blend with industry, roadways, and hot sunny days. Understanding the significance of this phenomenon and the actions they call for is important to safeguarding your health.

Metro Detroit got its earliest Ozone Action Day ever on April 15, 2023, when temps hit 83 degrees. Because heat is one of the ingredients in forming ground-level ozone, the warmer springs and summers we see with climate change may mean an earlier start to the ozone season. The normal high temperature in April in the Detroit area is 58.7 degrees.

The number of above-normal summer days in Detroit has increased by 22 since 1970, while the number of above-normal spring days has increased by 13 since 1991, according to climate data organization Climate Central. Since temperature is one of the ingredients needed to make ozone, it stands to reason we’ll be seeing more ozone as the climate continues to warm, other things being equal.

Climate Central

What is ground-level ozone and how is it formed?

Ground-level ozone, often called “bad ozone,” is a harmful air pollutant that forms near the Earth’s surface. It differs from the “good ozone” in the stratosphere, which protects us from the sun’s harmful ultraviolet (UV) radiation. Ground-level ozone is not emitted directly into the air but is created through chemical reactions between nitrogen oxides (NOx) and volatile organic compounds (VOCs) in sunlight.

Sources of nitrogen oxides and volatile organic compounds include vehicle exhaust, industrial emissions, power plants, gasoline vapors, and chemical solvents. When these pollutants are released into the atmosphere, they undergo a series of complex chemical reactions facilitated by sunlight. As a result, ground-level ozone is formed.

Ozone pollution tends to be more prevalent in urban and industrial areas, with higher concentrations of vehicles and industrial activities. Factors such as weather conditions, temperature, and sunlight intensity also influence the formation and accumulation of ground-level ozone.

Ground-level ozone’s problem is its harmful effects on human health and the environment. Breathing in ozone can cause respiratory problems, such as coughing, throat irritation, chest discomfort, and worsened asthma symptoms. It can also have detrimental effects on plant life, including reduced crop yields and damage to vegetation.

Who calls an Ozone Action Day, and how do they make the decision?

Meteorologists in the Michigan Department of Environment, Great Lakes and Energy are tasked with forecasting air pollutants. During the winter, they focus on forecasting PM2.5, a pollutant related to smoke and small dust particles. In the summer, ozone becomes the main concern.

Ozone varies with weather patterns, so forecasts are done for shorter periods, usually 1-2 days. Ozone action days are declared when predicted levels exceed 70 parts per billion, a threshold set by the U.S. Environmental Protection Agency under the Clean Air Act.

Meteorologists consider temperature, dew points, low winds, and wind direction when making forecasts. Higher temperatures, higher dew points, and wind stagnation tend to drive up ozone; so does the presence of particulate pollution, which can blow in from industrial areas like Chicago, Gary, Indiana, Cleveland and Toledo, Ohio.

Meteorologists rely on forecasting models but acknowledge that they can sometimes be inaccurate by overpredicting or underpredicting. Their personal knowledge and experience living in Michigan for many years help them compensate for the limitations of the models, particularly in understanding the regional aspects of forecasting in the area, according to EGLE meteorologist Alec Kownacki.

What should I do on an Ozone Action Day?

On an Ozone Action Day, the primary goal is to reduce your contribution to ozone pollution and protect air quality. Here are some actions you can take on an Ozone Action Day:

Consider carpooling, using public transportation, biking, or walking instead of driving alone. By reducing the number of vehicles on the road, you can help decrease emissions that contribute to ozone formation.

Avoid refueling your vehicle during the day. If you need to refuel your vehicle, try to do it during cooler hours, such as early morning or late evening. This helps prevent gasoline vapors from evaporating and reacting with sunlight to form ozone.

Reduce electricity usage during peak hours by minimizing the use of appliances, lights, and electronics. Lowering your energy consumption helps reduce emissions from power plants, which can contribute to ozone formation.

Postpone or limit outdoor activities: If possible, reschedule outdoor activities to a day with better air quality. If you need to spend time outdoors, try to do so during the early morning or late evening when ozone levels are lower.

Avoid using gasoline-powered lawnmowers, leaf blowers, and other garden equipment on Ozone Action Days. If you must use them, try to do so during the cooler hours of the day.

Share information about Ozone Action Days with your friends, family, and coworkers. Encourage them to take similar actions to reduce their impact on air quality.

Stay updated on air quality reports and forecasts in your area. Check local news sources or websites that provide air quality information so that you can plan your activities accordingly.

Learn more at SEMCOG’s website.

What impact can breathing ground-level ozone have on my health?

Breathing ground-level ozone can have various impacts on your health. Ozone can irritate and inflame the airways, leading to coughing, throat irritation, chest discomfort, and shortness of breath. People with pre-existing respiratory conditions like asthma or chronic obstructive pulmonary disease (COPD) may experience worsened symptoms.

Ozone exposure can reduce lung function, making it harder to breathe. This can be particularly problematic for individuals with respiratory conditions or older adults. Ozone can also weaken the immune system in the respiratory tract, making people more susceptible to respiratory infections such as bronchitis and pneumonia.

Studies suggest that breathing ozone may increase the risk of cardiovascular problems, including heart attacks, strokes, and heart disease, particularly in individuals with existing cardiovascular conditions. And recent research indicates that ozone exposure may have systemic effects beyond the respiratory system, potentially impacting other organs and systems in the body.

It’s important to note that the severity of health effects can vary depending on a person’s sensitivity, the duration and intensity of exposure, and overall air quality. Vulnerable populations such as children, older adults, and individuals with respiratory or cardiovascular conditions are at higher risk and may experience more significant health impacts from ozone exposure.

To protect your health, experts advise staying informed about ozone levels in your area, especially during Ozone Action Days or when air quality alerts are issued. Taking precautions such as limiting outdoor activities during peak ozone hours, staying in air-conditioned environments, and following any recommendations or guidelines provided by local health authorities can help minimize your exposure and reduce potential health risks.

How bad is ozone in general in Metro Detroit?

The Environmental Protection Agency determined that southeast Michigan has met all federal standards for ground-level ozone as of May 2023. The region had been a non-attainment area for ozone under the federal Clean Air Act since 2018.

The decision followed an EGLE request that the EPA discount certain air quality data measured on June 24 and 25, 2022, at a monitor in Detroit. By ignoring that data, the region’s overall air quality measurements across a network of six monitors fell below the National Ambient Air Quality Standards for ozone, and, as a result, the decision paved the way for EPA to grant EGLE’s request.

Ground-level ozone levels have declined nationwide since the 1980s due to improved vehicle emission technology and industrial pollution restrictions under the Clean Air Act. Southeast Michigan’s ozone levels have followed the same trend.

“Across the United States, regulations have succeeded in bringing ozone levels down,” said Dr. Charlie Weschler, a professor in the Environmental and Occupational Health Sciences Institute at Rutgers University. “I’m in my middle 70s. When I was in high school and college, ozone levels would get much higher. It wasn’t unusual to have ozone levels in the Detroit area that were over 100 ppb on warm summer days. “

Regulations on automobile motor vehicle exhaust have limited the amount of nitrogen oxide that comes out of tailpipes, and regulations on industry have reduced organic compounds from the stacks.

Planet Detroit

However, areas near polluting sources and roadways may still face unhealthy ozone levels.

Nick Leonard, who directs the nonprofit advocacy group Great Lakes Environmental Law Center, called the EPA’s decision “severely disappointing,” saying it prioritizes polluters over some of Detroit’s most vulnerable residents.

How can I protect myself and my family during times of high ozone?

When ozone levels are high, physicians often see patients struggling with breathing problems.

“We see patients with exacerbations or worsening of respiratory symptoms from asthma and chronic obstructive pulmonary disease,” said Daniel R Ouellette, MD, a pulmonary disease and critical care medicine specialist with Henry Ford Health System. Oulette recommends patients with these problems stay inside, use air conditioning, and avoid aerobic activities, as ozone may cause damage and inflammation in the lungs and bronchial tubes.

Here are some additional measures you can take:

  • Stay updated on air quality conditions in your area. Check air quality forecasts, local news, or reliable air quality monitoring websites/apps like AirNow to know when ozone levels are elevated and plan accordingly.
  • Try to schedule outdoor activities when ozone levels are lower, usually in the early morning or evening. Avoid outdoor activities during peak ozone hours, typically in the afternoon when the sun is strongest. When spending time outdoors, seek shade or areas with reduced sun exposure. If possible, spend time in air-conditioned or well-ventilated indoor spaces to minimize exposure to ozone.
  • Limit strenuous outdoor activities that can increase your breathing rate and the amount of ozone you inhale. If you engage in physical activities, consider reducing the intensity and taking more frequent breaks in shaded or air-conditioned areas.
  • If you must be outdoors during high ozone periods, consider wearing a mask or a respirator designed to filter out fine particles, including ozone. N95 or N99 masks can provide some protection, but consult a healthcare professional to determine the most appropriate option.
  • Keep indoor air quality as healthy as possible by closing windows and using air purifiers with HEPA filters to reduce indoor pollutant levels. Avoid using products that release VOCs, such as certain cleaning agents, aerosol sprays, and scented candles.
  • If you or any family members have pre-existing respiratory or cardiovascular conditions, follow the advice of healthcare professionals. Ensure you have an adequate supply of medications and seek medical attention promptly if symptoms worsen during high ozone periods.

You can also take action to reduce your contribution to ozone pollution. Opt for eco-friendly transportation alternatives like walking, biking, or public transit. Minimize vehicle use, carpool when possible, and avoid idling your vehicle.

How might climate change impact ground-level ozone and Ozone Action Days?

Climate change may extend the ozone season, causing it to start earlier in the spring and last longer into the fall. As temperatures rise earlier in the year and remain elevated for extended periods, the conditions conducive to ozone formation persist for a greater duration, increasing the potential for Ozone Action Days.

“To the extent that outdoor temperatures are increasing because of climate change, especially during certain periods of the year, and to the extent that we have more really hot days in Detroit, we’re likely to have more ozone action days,” Weschler said. “But you see how tricky it is because Detroit today has much cleaner air than Detroit did 40 or 50 years ago. If you had these same temperatures 40 or 50 years ago, your ozone levels would have been higher.”

Dr. Owen Cooper is a senior research scientist in the National Oceanic and Atmospheric Administration Chemical Sciences Laboratory and a research associate at the University of Colorado, Boulder Cooperative Institute for Environmental Sciences. He concurs that because air is cleaner overall, the “climate penalty” for air quality — the impacts of climate change on surface air pollution — will be smaller than in other areas f the world with worse air pollution, like South and East Asia.

“In the USA and Europe, air pollution emissions are expected to decline, and therefore the climate penalty in these regions will be quite small,” Cooper said. “The take-home message is that even though we expect climate change to exert a climate penalty on ozone pollution, its impact will be very limited if air pollution emissions continue to decline.”

Rising temperatures associated with climate change can accelerate the formation of ground-level ozone. Ozone production increases with higher temperatures as the chemical reactions that create ozone become more efficient. This can lead to elevated ozone levels and more frequent Ozone Action Days, particularly in regions already prone to ozone pollution.

Climate change can alter weather patterns, including wind, precipitation, and atmospheric stability. These changes can affect the transport and dispersion of ozone precursors and pollutants, potentially leading to localized ozone-level variations.

Warmer temperatures can increase the release of volatile organic compounds (VOCs) release from sources like vegetation and industrial activities. VOCs react with nitrogen oxides in the presence of sunlight to form ozone. As climate change influences ecosystems and human activities, the emission of VOCs may change, impacting ozone levels.

How can I monitor ozone in my area and get air quality alerts?

Check online platforms that provide real-time air quality information, such as the U.S. Environmental Protection Agency’s AirNow website (www.airnow.gov), which includes an Air Quality Index map showing ozone levels and other pollutants in the region. You can also sign up for email air quality alerts (including Ozone Action Alerts) in the region via AirNow’s EnviroFlash. And you can view real-time air quality monitors for ozone and PM2.5 on EGLE’s website.

There are also various smartphone apps and websites available that provide real-time air quality information. Examples include AirVisual, Plume Labs’ Air Report, and BreezoMeter. These apps often use data from monitoring stations and provide localized air quality information based on your location.

There’s also a growing community-based monitoring system in Detroit. Check out the JustAir Network and the Ecology Center’s Community Air Quality Networks, and you may be able to get involved.

You might consider purchasing a portable air quality monitor that measures ozone levels. These devices allow you to check the air quality in your immediate surroundings. However, it’s important to choose a reliable and accurate monitor and follow the manufacturer’s instructions for proper usage.

Some popular examples include:

Aeroqual offers a range of portable air quality monitors designed for personal and professional use. Their devices measure various pollutants, including ozone, particulate matter, nitrogen dioxide, and more.

Temtop manufactures portable air quality monitors that provide real-time data on PM2.5, PM10, CO2, TVOC, and formaldehyde. They offer different models with varying features and price ranges.

IQAir produces portable air quality monitors known as “AirVisual Pro.” These devices measure key pollutants, display real-time data, and provide personalized recommendations based on air quality conditions.

PurpleAir monitors have gained popularity due to their affordability, user-friendly interface, and ability to access data from multiple monitoring stations. However, it’s important to note that while these monitors are useful for tracking PM2.5 levels, they do not measure other pollutants, such as ozone or specific gases.

Planet Detroit originally published this story. Sign up for Planet Detroit's weekly newsletter here.

This article first appeared on Planet Detroit and is republished here under a Creative Commons license.

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