What is a bad level of ozone?
Unhealthy (151-200) The following groups should avoid prolonged outdoor exertion: People with lung disease, such as asthma • Children and older adults • People who are active outdoors • Everyone else should limit prolonged outdoor exertion.
What are acceptable ozone levels?
Regulatory Ozone Limits Current OSHA regulations set an eight-hour time-weighted average permissible exposure limit (PEL-TWA) of 0.1 ppm (0.2 mg/m³). NIOSH sets a ten-hour recommended exposure limit ceiling (REL-C) at the same value, 0.1 ppm (0.2 mg/m³).
What is the EPA standard for ozone?
0.070 ppm
Based on extensive scientific evidence about the effects of ozone on public health and welfare, on October 1, 2015, EPA strengthened the ground-level ozone standard to 0.070 ppm, averaged over an 8-hour period.
What is 8hr ozone?
0.08 ppm
Federal Standards Areas in the United States where ozone levels measured in the ambient air exceed the 8-hour standard of 0.08 ppm(v) are said to be in nonattainment of this standard. The 8-hour ozone NAAQS is based on the number of days per year with a 8-hour average concentration of 0.08 ppm(v) or greater.
What is bad ozone and good ozone?
Here, ground- level or “bad” ozone is an air pollutant that is harmful to breathe and it damages crops, trees and other vegetation. The stratosphere or “good” ozone layer extends upward from about 6 to 30 miles and protects life on Earth from the sun’s harmful ultraviolet (UV) rays.
Why is ozone pollution bad?
It can lead to worse conditions like damaged airways, chronic bronchitis, asthma, and emphysema. Even if symptoms have disappeared, ozone can continue to damage the lungs. Ground-level ozone can also damage vegetation and ecosystems. The pollutant can cause mass die-off in crops, reducing growth and increasing disease.
Is ozone regulated by EPA?
The Clean Air Act requires EPA to set national ambient air quality standards (NAAQS) for ozone and five other pollutants considered harmful to public health and the environment (the other pollutants are particulate matter, nitrogen oxides, carbon monoxide, sulfur dioxide and lead).
Where is the bad ozone found and why is it bad?
“Bad” ozone is found in the troposphere, the layer nearest the ground. Tropospheric ozone is a harmful pollutant which forms when sunlight alters various chemicals emitted by humans. “Good” ozone forms in the stratosphere, the next higher layer where some jet planes fly.
Why is ozone harmful to humans?
When inhaled, ozone can damage the lungs. Relatively low amounts of ozone can cause chest pain, coughing, shortness of breath and, throat irritation. It may also worsen chronic respiratory diseases such as asthma as well as compromise the ability of the body to fight respiratory infections.
Is ozone bad for the environment?
Ozone occurs both in the Earth’s upper atmosphere and at ground level. Ozone at ground level is a harmful air pollutant, because of its effects on people and the environment, and it is the main ingredient in “smog.” Learn more about air emission sources.
How is ozone good and bad?
Stratospheric ozone is “good” because it protects living things from ultraviolet radiation from the sun. Ground-level ozone, the topic of this website, is “bad” because it can trigger a variety of health problems, particularly for children, the elderly, and people of all ages who have lung diseases such as asthma.