During summer, ground-level ozone increases
In the stratosphere 6-10 miles above the Earth’s surface, ozone is formed when rays of sunlight strike oxygen molecules. This ozone layer is a natural process and beneficial, as it absorbs ultraviolet rays before they reach the Earth’s surface.
But close to the ground, ozone is formed as the result of a different process. At this level, chemicals from industrial sources, vehicle exhaust and other combustion products mix and form ozone in the presence of heat and sunlight. Ground-level ozone is a respiratory health hazard and is the main component of smog.
How ozone can hurt you
Ground-level ozone can cause irritation of the airways, reduced lung function and asthma flare-ups. It can also aggravate emphysema and bronchitis, and can reduce the body’s ability to fight infections.
According to the U.S. Environmental Protection Agency (EPA), ozone can cause muscles in the airways to constrict, trapping air in the alveoli (tiny air sacs in the lungs). This leads to wheezing and shortness of breath, and can trigger asthma symptoms. Ozone also causes airway inflammation as a result of increased mucus production and fluid accumulation and retention. This can kill cells lining the airways and is comparable to skin inflammation caused by sunburn.
Summer and Air Quality Action Days
Because ground-level ozone is formed in the presence of heat and sunlight, ozone levels peak in the summertime. On some days, levels may be so high that your local or state air quality agency declares an Air Quality Action Day. This means ground-level ozone has reached an unhealthy level based on the Air Quality Index (AQI).
A color-coded system denotes the health effect risks associated with each AQI level. The AQI levels for ozone are:
|No health impacts are expected.
|Unusually sensitive people should limit outdoor exertion.
|Active children and adults, and people with respiratory diseases should limit outdoor exertion.
|Active people and those with respiratory diseases should avoid prolonged outdoor exertion; all others should limit outdoor exertion.
|Active people and those with respiratory diseases should avoid all outdoor exertion; everyone else should limit outdoor exertion.
What to do when ozone levels rise
The best way to reduce exposure to ozone during the summer months is to monitor ozone levels where you live and be prepared to take action when ozone levels are highest. Here are a few suggestions:
1. Monitor the air quality where you live. Websites such as www.airnow.gov allow you to check the current air quality, including ozone levels, by ZIP code.
2. Stay indoors as much as possible on unhealthy air quality days. According to the EPA, indoor concentrations of ozone vary between 20% and 80% of outdoor levels, depending on whether windows are open or closed, air conditioning is being used, etc.
3. Use an air purifier with activated carbon filtration. Studies have shown that activated carbon filters can be very effective at ozone removal. IQAir room systems including the New Edition HealthPro® Series and the GC™ MultiGas system contain high-quality activated carbon from bituminous coal to reduce ozone levels. Air purifiers that intentionally produce ozone should always be avoided, as ozone is a lung irritant.
This online publication is brought to you by The IQAir Group, which develops innovative air quality solutions for indoor environments around the globe. IQAir is the exclusive educational partner of the American Lung Association for the air purifier industry.