ozone layer
Most ozone (about 90%) is found in the stratosphere, which begins about 10–16 kilometers (6–10 miles) above Earth’s surface and extends up to about 50 kilo- meters (31 miles) altitude. The stratospheric region with the highest ozone concentration is commonly known as the “ozone layer” (see Figure Q1-2).
Is the ozone concentration decreasing?
Research published in American Chemistry and Physics shows that there continues to be a decrease in stratospheric ozone (O₃), despite a detectable increase in the ozone levels in the upper stratosphere and at the poles.
What is causing the earth’s ozone level to decrease?
Ozone depletion occurs when chlorofluorocarbons (CFCs) and halons—gases formerly found in aerosol spray cans and refrigerants—are released into the atmosphere (see details below). CFCs and halons cause chemical reactions that break down ozone molecules, reducing ozone’s ultraviolet radiation-absorbing capacity.
Between what latitudes is the ozone layer found in highest concentration?
During spring, total ozone exhibits maximums at latitudes poleward of about 45°N in the Northern Hemisphere and between 45° and 60°S in the Southern Hemisphere. These spring maximums are a result of increased transport of ozone from its source region in the tropics toward high latitudes during late autumn and winter.
Which layer is rich in ozone?
The ozone layer is the common term for the high concentration of ozone that is found in the stratosphere around 15–30km above the earth’s surface. It covers the entire planet and protects life on earth by absorbing harmful ultraviolet-B (UV-B) radiation from the sun.
What is the bad 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.
What is the hottest layer of the atmosphere?
thermosphere
The thermosphere is often considered the “hot layer” because it contains the warmest temperatures in the atmosphere. Temperature increases with height until the estimated top of the thermosphere at 500 km. Temperatures can reach as high as 2000 K or 1727 ºC in this layer (Wallace and Hobbs 24).
Which is the hottest layer of the atmosphere?
The thermosphere
Where is the bad ozone located?
troposphere
“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.
Is it safe to breathe in ozone?
When inhaled, ozone can damage the lungs. Relatively low amounts can cause chest pain, coughing, shortness of breath and throat irritation. Ozone may also worsen chronic respiratory diseases such as asthma and compromise the ability of the body to fight respiratory infections.
Can you smell ozone?
Ozone has a distinctive smell that humans can detect even in small concentrations — as few as 10 parts per billion.
How ozone is depleted?
Ozone Depletion. When chlorine and bromine atoms come into contact with ozone in the stratosphere, they destroy ozone molecules. One chlorine atom can destroy over 100,000 ozone molecules before it is removed from the stratosphere. When they break down, they release chlorine or bromine atoms, which then deplete ozone.
Does CO2 destroy the ozone layer?
Carbon dioxide has no direct effect on ozone, unlike CFCs and HFCs. Higher levels of carbon dioxide, however, do have an indirect effect on the ozone layer in the stratosphere. But near the poles and in the upper stratosphere, CO2 is increasing the amount of ozone by preventing nitrogen oxide from breaking it down.
What layer do we live in?
The Troposphere
The Troposphere: Beginning at the surface of Earth, the troposphere extends to around seven miles up. This is the layer we live in and contains most of what we consider to be “the atmosphere”, including the air we breathe and nearly all of the weather and clouds we see.
What decreases the ozone layer?
Between what altitudes is the ozone layer found in highest concentrations?
Most ozone (about 90%) is found in the stratosphere, which begins about 10–15 kilometers (km) above Earth’s surface and extends up to about 50 km altitude. The stratospheric region with the highest concentration of ozone, between about 15 and 35 km altitude, is commonly known as the “ozone layer” (see Figure Q1-2).
What causes high ozone levels?
This happens when pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources chemically react in the presence of sunlight. Ozone is most likely to reach unhealthy levels on hot sunny days in urban environments, but can still reach high levels during colder months.
Ozone occurs in two layers of the atmosphere. The layer closest to the Earth’s surface is the troposphere. Here, ground- level or “bad” ozone is an air pollutant that is harmful to breathe and it damages crops, trees and other vegetation. It is a main ingredient of urban smog.
At what concentration can you smell ozone?
0.0076 parts-per- million
The word “ozone” is derived from the Greek word for “smell.” Its odor can be detected when very low concentrations are present, as low as 0.0076 parts-per- million (ppm). At low concentrations ozone has a sweet, clover-like odor often noted outdoors after an electrical storm.
Does the ozone hole cause global warming?
Ozone depletion and climate change are linked in a number of ways, but ozone depletion is not a major cause of climate change. Atmospheric ozone has two effects on the temperature balance of the Earth. It absorbs solar ultraviolet radiation, which heats the stratosphere.
What does ozone smell like?
Here are some of the ways the smell of ozone is described: Like a burning wire. Like chlorine. A “clean” smell. Sweet and pungent.
Why hydrofluorocarbons are no harm to the ozone layer?
“HFCs are, in fact, weak ozone-depleting substances.” While HCFCs contain chlorine atoms, they are less damaging to the ozone layer because they also contain hydrogen atoms, which causes them to break down in the atmosphere faster. HCFCs are currently being phased out in favor of HFCs, which do not contain chlorine.
What’s the maximum concentration of ozone you can be exposed to?
The Occupational Safety and Health Administration (OSHA) requires that workers not be exposed to an average concentration of more than 0.10 ppm for 8 hours. The National Institute of Occupational Safety and Health (NIOSH) recommends an upper limit of 0.10 ppm, not to be exceeded at any time.
How does ozone affect the quality of air?
Available scientific evidence shows that, at concentrations that do not exceed public health standards, ozone is generally ineffective in controlling indoor air pollution. The concentration of ozone would have to greatly exceed health standards to be effective in removing most indoor air contaminants.
How is ozone destroyed in the lower stratosphere?
The chemical shorthand for these gas-phase reactions is: The overall effect is a decrease in the amount of ozone, though the rate of these processes can be decreased by the effects of null cycles. More complicated mechanisms have also been discovered that lead to ozone destruction in the lower stratosphere. 2 ).
Where are the ozone transport regions in the United States?
The Ozone Transport Region includes Maine, New Hampshire, Vermont, Massachusetts, Connecticut, Rhode Island, New York, New Jersey, Pennsylvania, Maryland, Delaware, the northern counties of Virginia, and the District of Columbia and is headed up by the Ozone Transport Commission (OTC).
