DETROIT – Air quality was forecast to be “unhealthy for sensitive groups” on Monday across Metro Detroit.

Pollutants were expected to combine with hot temperatures to create “bad” ozone across Metro Detroit by the afternoon. High temperatures were forecast to reach the mid-90s on Monday, June 17, and will feel even warmer because of the humidity.

An air quality alert, also known as an “ozone action day,” was issued for Monday in Livingston, Macomb, Monroe, Oakland, St. Clair, Washtenaw and Wayne counties. The air quality index, known as the AQI, was expected to enter the “unhealthy for sensitive groups” range, which is between a 101-150 AQI. An AQI above 300 is considered hazardous.

At this range, most people won’t be affected by the poorer air quality.

However, those in “sensitive groups” — such as young children, older adults, or those with asthma or other respiratory issues — may be impacted by breathing in the air, especially over a long period of time. They’re encouraged to reduce exposure to the ozone by “choosing less strenuous activities” or spending less time outside.

The “ozone action day” title is also meant to encourage people to avoid activities that can lead to ozone formation, including refueling vehicles, using gas-powered lawn equipment, and using charcoal lighter fluid.

“At the earth’s surface, ozone comes into direct contact with life-forms and displays its destructive side (hence, it is often called ‘bad ozone’),” according to the National Oceanic and Atmospheric Association. “Because ozone reacts strongly with other molecules, high levels of ozone are toxic to living systems.”

Officials say the bad ozone may continue to affect Southeast Michigan for the next few days, at least.

“With winds at all levels of the atmosphere coming from the hot southwest, Air Quality will certainly be an issue, this week,” according to AirNow.gov, a federal platform created through a partnership with the EPA, CDC, National Oceanic and Atmospheric Administration, and more.

—> Heat wave hits Metro Detroit this week: What to know

What causes “bad” ozone?

“Bad” ozone is found at ground level. In cities, it’s made when emissions from vehicles, power plants, chemical plants, and other sources react with heat and sunlight. The hotter the day and the stronger the sun, the more ozone is formed. That’s why ozone is usually worst on windless, hot summer afternoons. High levels of ozone are mainly a concern for people from April 1–September 30.

You’re most likely to find high levels of “bad” ozone in urban areas. You might hear it called “smog.” However, other areas can also have high ozone levels when winds blow pollution hundreds of miles from their original sources.

How does “bad” ozone affect people?

Even at low levels, breathing ozone can cause chest pains, coughing, and throat irritation. It can also aggravate lung diseases like emphysema, bronchitis, and asthma. The more ozone pollution a person breathes, the more permanent damage it can do to her lungs.

Because it usually forms in hot weather, anyone who spends time outdoors in the summer may be affected – children, older people, outdoor workers, and people exercising may be particularly susceptible. The higher the ozone level, the more people who will experience health symptoms. Millions of Americans live in areas where ozone levels are higher than the national health standards, and should pay attention to ozone levels when the weather is hot and sunny.

Staying safe amid air quality alert

Follow these simple tips to stay safe when there is an air quality alert:

• Stay inside if possible, particularly if you have respiratory concerns or other health problems, are a senior or child.

• If you must go out, try to limit the amount of time you are out to strictly essential activities.

• Minimize your use of items that increase pollution, such as cars, gas powered lawn mowers and other vehicles.

• Do not burn debris or other items during an air quality alert.

• Take the bus, carpool, telecommute, bike, or walk. You’ll reduce traffic congestion and air pollution as well as save money.

• If you plan to barbecue, use an electric starter or charcoal chimney instead of lighter fluid. Fumes from the fluid contribute to ozone formation.

• Avoid drive-thru facilities or other situations where your vehicle idles for an extended period of time. You’ll save money on gas and reduce pollution.

Who is most at risk?

Several groups of people are particularly sensitive to ozone, especially when they are active outdoors. This is because ozone levels are higher outdoors, and physical activity causes faster and deeper breathing, drawing more ozone into the body.

• People with lung diseases, such as asthma, chronic bronchitis, and emphysema, can be particularly sensitive to ozone. They will generally experience more serious health effects at lower levels. Ozone can aggravate their diseases, leading to increased medication use, doctor and emergency room visits, and hospital admissions.

• Children, including teenagers, are at higher risk from ozone exposure because they often play outdoors in warmer weather when ozone levels are higher, they are more likely to have asthma (which may be aggravated by ozone exposure), and their lungs are still developing.

• Older adults may be more affected by ozone exposure, possibly because they are more likely to have pre-existing lung disease.

• Active people of all ages who exercise or work vigorously outdoors are at increased risk.

• Some healthy people are more sensitive to ozone. They may experience health effects at lower ozone levels than the average person even though they have none of the risk factors listed above. There may be a genetic basis for this increased sensitivity.

In general, as concentrations of ground-level ozone increase, more people begin to experience more serious health effects. When levels are very high, everyone should be concerned about ozone exposure.

What are the health effects?

Ozone affects the lungs and respiratory system in many ways. It can:

• Irritate the respiratory system, causing coughing, throat soreness, airway irritation, chest tightness, or chest pain when taking a deep breath.

• Reduce lung function, making it more difficult to breathe as deeply and vigorously as you normally would, especially when exercising. Breathing may start to feel uncomfortable, and you may notice that you are taking more rapid and shallow breaths than normal.

The risk of exposure to unhealthy levels of ground-level ozone is greatest during warmer months. Children, who often play outdoors in warmer weather, are at higher risk.

• Inflame and damage the cells that line the lungs. Within a few days, the damaged cells are replaced and the old cells are shed—much like the way your skin peels after sunburn. Studies suggest that if this type of inflammation happens repeatedly, lung tissue may become permanently scarred and lung function may be permanently reduced.

• Make the lungs more susceptible to infection. Ozone reduces the lung’s defenses by damaging the cells that move particles and bacteria out of the airways and by reducing the number and effectiveness of white blood cells in the lungs.

• Aggravate asthma. When ozone levels are unhealthy, more people with asthma have symptoms that require a doctor’s attention or the use of medication. Ozone makes people more sensitive to allergens—the most common triggers for asthma attacks. Also, asthmatics may be more severely affected by reduced lung function and airway inflammation. People with asthma should ask their doctor for an asthma action plan and follow it carefully when ozone levels are unhealthy.

• Aggravate other chronic lung diseases such as emphysema and bronchitis. As concentrations of ground-level ozone increase, more people with lung disease visit doctors or emergency rooms and are admitted to the hospital.

• Cause permanent lung damage. Repeated short-term ozone damage to children’s developing lungs may lead to reduced lung function in adulthood. In adults, ozone exposure may accelerate the natural decline in lung function that occurs with age.

Sources: AQI, NWS, EPA, SEMCOG.