Ozone in the air has increased by 40 percent since the industrial revolution, has revealed analysis of 150-year-old snow and ice.
The greenhouse gas is created when pollutants from cars and factories react with sunlight.
Now the first study of its kind has withstood the fear that it is fueling the increase in asthma and other lung diseases.
It is based on ice cores and compressed snow from Antarctica and Greenland that contain a history of concentrations over more than 150 years.
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Ozone in the sky has increased by 40 percent since the industrial revolution, analysis of 150-year-old snow and ice (photo) has revealed. The greenhouse gas is created when pollutants from cars and factories react with sunlight
Ozone molecules do not remain trapped in ice and snow – but oxygen chemicals do, so his team has measured the quantities of two of these trapped in air bubbles.
Known as oxygen-16 and 18 isotopes, respectively, the production of ozone in the atmosphere changes their share.
The analysis showed the rise in ground level, or tropospheric ozone since 1850, was around 40 percent.
This is much smaller than the increases indicated by observations from the 19th century – and consistent with the figures predicted by computer models.
Lead author Laurence Yeung of Rice University in the US said: & We have been able to keep track of how much ozone there was in the old atmosphere.
& # 39; This has not been done before – and it is remarkable that we can do it at all.
These results show that the best models of today simulate ozone concentrations in the troposphere.
& # 39; That strengthens our confidence in their ability to predict how tropospheric ozone levels will change in the future.
& # 39; These measurements limit the amount of warming caused by anthropogenic ozone. & # 39;
The first study of its kind has resisted the fear that it will fuel the increase in asthma and other lung diseases. Pictured: Rice University geochemists Laurence Yeung and Asmita Banerjee
The most recent report from the Intergovernmental Panel on Climate Change (IPCC) estimated that ozone in the lower atmosphere of the Earth today contributes 0.4 watts per square meter of radiation forcing to the climate on the planet.
But the margin of error for that prediction was 50 percent – or 0.2 watts per square meter.
Dr. Yeung said: & # 39; That's a very big error bar. Better pre-industrial ozone estimates can significantly reduce those uncertainties.
& # 39; It is just like guessing how heavy your suitcase is if there is a fee for bags over 50 kilos.
& # 39; With the old error bars you would say: & # 39; I think my bag is between 20 and 60 pounds. & # 39; That is not good enough if you cannot afford to pay the fine. & # 39;
WHAT IS THE OZONE LAYER?
Ozone is a molecule that consists of three oxygen atoms that naturally occur in small amounts.
In the stratosphere, about seven to 25 miles above the earth's surface, the ozone layer acts as a sunscreen, protecting the planet against potentially harmful ultraviolet rays that can cause skin cancer and cataracts, suppress immune systems and also damage plants.
It is produced in tropical latitudes and spread throughout the world.
Closer to the ground, ozone can also be created by photochemical reactions between the sun and pollution from vehicle exhausts and other sources, creating harmful smog.
Although warmer-than-average stratospheric weather conditions have reduced ozone depletion in the last two years, the current ozone hole area is still large compared to the 1980s when the depletion of the ozone layer over Antarctica was first discovered.
In the stratosphere, about seven to 25 miles above the earth's surface, the ozone layer acts as a sunscreen and protects the planet against potentially harmful ultraviolet rays
This is because the amounts of ozone-depleting substances such as chlorine and bromine remain high enough to cause significant ozone loss.
In the 1970s, it was recognized that chemicals known as CFCs, used for example in cooling and spray cans, destroyed ozone in the stratosphere.
Agreement was reached on the Montreal Protocol in 1987, which led to the gradual elimination of CFCs and, recently, the first signs of ozone layer recovery in Antarctica.
The upper stratosphere at lower latitudes also shows clear signs of recovery, proving that the Montreal protocol works well.
But the new study, published in Atmospheric Chemistry and Physics, found that it is unlikely to recover at latitudes between 60 ° N and 60 ° S (London is at 51 ° N).
The cause is not certain, but the researchers believe that it is possible that climate change may change the pattern of atmospheric circulation, thereby draining off more ozone from the tropics.
They say that another possibility is that substances with a very short lifespan (VSLS & # 39; s), which contain chlorine and bromine, can destroy ozone in the lower stratosphere.
VSLS & # 39; s include chemicals that are used as solvents, paint strippers, and as degreasers.
One is even used in the production of an ozone-friendly replacement for CFCs.
Most of the earth's ozone is in the stratosphere, which is more than five miles above the earth's surface.
This is also called & # 39; good & # 39; called ozone because it blocks most ultraviolet rays from the sun and is therefore essential for life on earth.
The rest of the earth's ozone layer is in the troposphere, closer to the surface. Here the reactivity of ozone can be harmful to plants, animals and people.
It is a major constituent of urban smog, which forms near the surface in sun-lighted reactions between oxygen and pollutants from motor vehicle exhaust gases.
The Environmental Protection Agency considers exposure to ozone concentrations of more than 70 parts per billion for eight hours or more unhealthy.
Dr. Yeung said: & # 39; The thing about ozone is that scientists have studied it in detail for only a few decades.
& # 39; We didn't know why ozone was so abundant in air pollution up to the 1970s. That is the moment when we started to recognize how air pollution changed atmospheric chemistry. Cars & # 39; s drove ozone on living level. & # 39;
Most of the earth's ozone is in the stratosphere, which is more than five miles above the earth's surface. This is sometimes called & # 39; good & # 39; called ozone because it blocks most ultraviolet rays from the sun and is therefore essential for life on earth.
While the earliest measurements of tropospheric ozone date back to the end of the 19th century, those data clash with the best estimates of current state-of-the-art atmospheric chemistry models.
Dr. Yeung said: & # 39; Most of those older data come from starch paper tests where the paper changes color after reacting with ozone.
& # 39; The tests are not the most reliable – for example, the color change depends on the relative humidity – but they nevertheless suggest that living-room ozone may have risen to 300 percent in the last century.
& # 39; The best computer models of today suggest a more moderate increase of 25 to 50 percent. That is a huge difference.
& # 39; There are simply no other data available, so it is hard to know what is correct, or both are correct, and those specific measurements are not a good measure of the entire troposphere.
& # 39; The community has been struggling with this question for a long time. We wanted to find new data that could make progress on this unresolved problem. & # 39;
With the start of industrialization and the burning of fossil fuels around 1850, people began to add more ozone to the lower atmosphere.
Dr. Yeung said: & # 39; One of the most exciting aspects was how well the ice core record matches model predictions.
& # 39; This was a case where we did a measurement, and independently a model produced something that was very close to the experimental evidence.
& # 39; I think it shows how far atmospheric and climate scientists have come to accurately predict how people change the Earth's atmosphere – especially its chemistry. & # 39;
The full findings of the study were published in the journal Nature.
WHAT ARE THE EFFECTS OF THE MOST IMPORTANT AIR POLLUTERS OF THE WORLD?
According to the Environmental Protection Agency, there are six major pollutants that can affect human health and well-being.
Fine dust: Particulate matter is the term for a mixture of solid particles and liquid droplets in the air.
These particles come in many sizes and shapes and can be composed of hundreds of different chemicals.
Some are emitted directly by a source, such as construction sites, unpaved roads, fields, chimneys, or fires.
Fine particles (2.5 parts per million) are the main cause of reduced visibility (haze) in parts of the United States, including many of our precious national parks and nature reserves.
Carbon monoxide: Breathing air with a high concentration of CO reduces the amount of oxygen that can be transported in the bloodstream to important organs such as the heart and brain.
At very high levels, which are possible inside or in other closed environments, CO can cause dizziness, confusion, unconsciousness and death.
Nitrogen dioxide: NItrogen dioxide mainly enters the air through the burning of fuel. NO
It forms emissions from cars, trucks and buses, power stations and off-road equipment.
Breathing air with a high NO concentration can irritate the respiratory tract in the human respiratory system. Such short-term exposure can exacerbate respiratory disorders, in particular asthma, leading to respiratory symptoms (such as coughing, panting, or difficulty breathing).
Sulfur dioxide: The largest source of sulfur dioxide in the atmosphere is the burning of fossil fuels by power plants and other industrial facilities.
Short-term exposure to SO can damage the human respiratory system and make breathing difficult. Children, the elderly and people with asthma are particularly sensitive to STD effects.
Ozone at ground level: The ozone layer in the lower part of the lower part of the stratosphere, about 12 to 19 miles above the surface of the planet (20 to 30 km).
Although ozone protects us against UV radiation, when found on the ground floor, it can cause health problems for vulnerable people suffering from lung diseases such as asthma.
It is made by chemical reactions between nitrogen oxides (NOx) and volatile organic compounds (VOC) – which are found in exhaust gases – in the presence of sunlight.
Lead: Important sources of lead in the air are ore and metal processing and aircraft with piston engines that run on leaded jet fuel.
Other sources are producers of waste incineration plants, utilities and lead-acid batteries. The highest air concentrations of lead are usually found in lead smelters.
Depending on the degree of exposure, lead can have a negative influence on the nervous system, kidney function, the immune system, reproductive and development systems and the cardiovascular system.
Infants and young children are particularly sensitive to even a low level of lead, which can contribute to behavioral problems, learning disabilities and reduced IQ.
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