Ozone is the main ingredient of urban smog and can be hazardous to your health. Even at low levels, ozone can cause a number of respiratory effects, especially in sensitive individuals or with repeated exposure. In central Arkansas, Ozone Action Days are declared whenever high concentrations of ground-level ozone are forecast.

Q. Is it hazardous to go outside on an Ozone Action Day?

A. It is perfectly safe to go outdoors on an Ozone Action Day. However, certain people who are more susceptible to the effects of ozone may wish to restrict their outdoor activities. Young children, the elderly, and people with weak respiratory systems should avoid strenuous outdoor activity. 

Healthy people may also experience reduced lung function on high ozone days and should avoid strenuous physical activity outdoors on very hot, sunny afternoons when there is little or no wind. If you experience respiratory distress, reduce exertion by slowing or stopping exercise. If symptoms persist, go indoors or seek medical attention.
 
 

A. The news media and other participating organizations are notified whenever an Ozone Advisory or Ozone Alert is declared. On these high ozone days, precautions should be taken to limit ozone exposure, especially for persons in sensitive groups. Persons in sensitive groups should routinely check the daily Air Quality Index (AQI) and the daily ozone forecast, which are reported in daily newspapers, on the Internet, NOAA Weather Radio, and other radio and television stations.

A. You can subscribe to EnviroFlash from the U.S. EPA.  This is a free service that provides you with information about the air quality in the location of your choice via a daily email.

Click here to access the EnviroFlash page.
 

A. There are two basic types of Ozone Action Days: an Ozone Advisory and an Ozone Alert. 

They are both related to the U.S. Environmental Protection Agency's Air Quality Index (AQI), which measures the health effects of breathing polluted air.

• An OZONE ADVISORY will be declared when the ozone forecast is code orange, indicating that prolonged outdoor exertion is unhealthy for sensitive groups such as children and people with asthma. Actions to reduce the formation of high ozone concentrations should be taken the day before a code orange day, as well as on code orange days.

• An OZONE ALERT will be declared when the ozone forecast is code red, indicating that prolonged outdoor exertion is unhealthy for everyone. Actions to reduce the formation of high ozone concentrations should be taken the day before a code red day, as well as on code red days.
 

• Unusually sensitive people should check the daily AQI and ozone forecast regularly and consider limiting their outdoor activities when the AQI is code yellow.

Click here for more about the AQI and Ozone Forecast

A. A third type of Ozone Action Day, an OZONE HEALTH ALERT, will be declared when the AQI is code purple. In the rare and unlikely event that an Ozone Health Alert occurs, everyone should limit outdoor exertion, while children and people with asthma or other breathing problems should avoid all outdoor exertion.

The Arkansas Department of Health will provide additional information to protect the public health if an Ozone Health Alert occurs.

Click here for ADH Health Warnings

A. Children, the elderly and people with weak or damaged respiratory systems are all at some risk. Damage to lung tissue may be caused by repeated ozone exposures, which is something like repeated sunburns of the lungs. This could result in reduced lung function and quality of life as people age.

• Active Children: Children are most at risk from exposure to ozone because their respiratory systems are still developing. Ground-level ozone is a summertime threat when children are outside playing and exercising at summer camps, pools, playgrounds, parks and backyards. An average adult breathes 13,000 liters of air per day. Children breathe even more per pound of body weight than adults.

• People with asthma or other respiratory diseases that make the lungs more vulnerable to the effects of ozone will generally experience health effects earlier and at lower ozone levels than less sensitive individuals. Ozone can aggravate asthma, causing more asthma attacks, increased use of medication, more medical treatment and more visits to hospital emergency clinics. More children than adults are asthmatic, and asthma is increasing alarmingly as a cause of death among children.

• Elderly People: Because elderly people tend to have weak respiratory and immune systems, they are highly susceptible to ozone related health risks.

• Healthy Adults: Even healthy adults can experience from 15 to more than 20 percent reduction in lung function from exposure to relatively low levels of ozone over several hours. Active adults who exercise or work vigorously outdoors have a higher level of exposure to ozone than people who are less active. Repeated exposure can cause lasting lung damage.

• Unusually Susceptible People: Some people may experience symptoms of ozone exposure at moderate levels of outdoor exertion or at lower levels of ozone than the average person.

Click here for Smog -- Who Does It Hurt?

• Ozone exposure can produce eye and throat irritation, coughing, and reduced lung function. When lung function is reduced, more rapid and shallow breaths can make breathing uncomfortable.

• Ozone can aggravate asthma. Because ozone can make people more sensitive to allergens, high ozone levels can trigger more asthma attacks and doctor visits.

• Ozone can aggravate chronic lung diseases, like bronchitis and emphysema, and reduce the immune system's ability to fight off bacterial infections in the respiratory system.

• Ozone can cause permanent lung damage. Repeated exposures to ozone can damage the developing lungs of children that lead to reduced lung function in adulthood. Repeated ozone exposure in adults can accelerate the natural decline in lung function that occurs as part of the aging process.
 
 

A. Ozone damage can occur without any noticeable signs, particularly in individuals that are exposed to high concentrations for several days in a row. Ozone exposure can continue to cause lung damage even when symptoms have disappeared. 

A. Ground-level ozone concentrations are more likely to exceed health standards on very hot (90+ degrees), sunny days with little or no wind. The stagnant air masses, which often occur in late summer, also tend to trap and hold ozone near the surface. High ozone concentrations usually occur between 10:00 a.m. and 8:00 p.m., with the worst times often occurring during the mid-to-late afternoon hours.

• Your chances of being affected by ozone increase the longer you are active outdoors and the more strenuous the activity you engage in. If you are involved in an activity that requires heavy exertion, reduce the time you spend on this activity or substitute another activity that requires more moderate exertion. For example, go for a walk rather than a jog.

• Activities that involve heavy exertion include playing basketball or soccer, chopping wood, heavy manual labor, and vigorous running, cycling or hiking.

• Activities that involve moderate exertion include climbing stairs, playing tennis or baseball, simple garden or construction work, and light jogging, cycling or hiking.

• Switch strenuous outdoor activities to early morning hours, when ozone levels are likely to be less concentrated.

• Postpone strenuous outdoor activities to a day when the ozone forecast is code green (or at least code yellow).

• To protect your health, check the ozone forecast regularly, especially on hot, sunny days with little or no wind.

Click here for the Daily Ozone Forecast
 

ozone@metroplan.org	Arkansas Department of Environmental Quality ozone@adeq.state.ar.us	Arkansas Department of Health ozone@arkansas.gov