Tuesday’s “Orange” air quality warning for Chicago and the surrounding counties (including northwest Indiana) has been extended through Wednesday, August 21. The predicted ozone Air Quality Index is over 100, indicating the air quality conditions are Unhealthy for Sensitive Groups.
What is meant by Unhealthy for Sensitive Groups?
“Unhealthy” here means certain groups may experience health effects from the air quality, but the general public is not likely to be affected. The groups depend on the type of pollution:
- Elevated Ozone levels: Individuals with lung disease, children, older adults, and people who are active outdoors are considered sensitive and therefore at greater risk.
- Particle pollution: People with heart or lung disease, older adults (starting at mid-40s for men and mid-50s for women), and children are considered sensitive and therefore at greater risk.
The AQI is an index for reporting daily air quality, indicating how clean or how unhealthy the air is. It is based on four major pollutants: ground level ozone, particle pollution, carbon monoxide, and sulfur dioxide. The AQI runs from zero to 500, with a value of 100 representing the national air quality standard for each of the pollutants. Values of 100 or below are considered satisfactory; at values over 100, the air is considered to be increasingly unhealthy.
What do the AQI values mean?
The AQI is divided into six levels of health concerns:
- AQI 0 to 50 = air quality Good – represented by the color green
- AQI 51 to 100 = air quality Moderate – represented by the color yellow
- AQI 101 to 150 = air quality Unhealthy for Sensitive Groups – represented by the color orange
- AQI 151 to 200 = air quality Unhealthy – represented by the color red
- AQI 201 to 300 = air quality Very Unhealthy – represented by the color purple
- AQI 301 to 500 = air quality Hazardous – represented by the color maroon
I’m not in a sensitive group, so when am I affected?
- At Unhealthy (AQI 151-200), everyone may begin to experience health effects from the pollution.
- At Very Unhealthy (AQI 201-300), a health alert is triggered, meaning everyone may experience more serious health effects.
- Hazardous (AQI 301-500) indicates emergency health conditions. The entire population is more likely to be affected by serious health effects.
What are the health effects of higher ozone levels?
- Irritation of the respiratory system, causing coughing, throat soreness, airway irritation, chest tightness, or chest pain when taking a deep breath.
- Reduced lung function, making it more difficult to breathe and leading to more rapid and shallow breaths than normal.
- Inflammation and damage to the cells that line the lungs, particularly with repeated exposure. Lung tissue may become permanently scarred and lung function may be permanently reduced. The lungs may also be more susceptible to infection.
- Aggravation of asthma. Ozone makes people more sensitive to allergens, the most common triggers for asthma attacks. In addition, asthmatics may also have reduced lung function and airway inflammation.
- Elevated ozone can aggravate other chronic lung diseases, such as emphysema and bronchitis.
- And 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.
How to adapt to a high ozone alert
Minimize Prolonged Exertion -- any outdoor activity that you’ll be doing off-and-on for several hours and that makes you breathe slightly harder than normal.
Minimize Heavy Exertion -- intense outdoor activities that cause you to breathe hard. It is very important to reduce your activity level if you experience any unusual coughing, chest discomfort, wheezing, breathing difficulty, or unusual fatigue.
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