January 27 - February 3
Question of the Week
Date: Fall 2014
How can you get rid of air pollution already in the air? Can we remove what we already have? Can you "suck" it out of the air? What can we do to get it out? Put it underground?
Answers from Our Expert Staff
Yes, scientists are trying to think of ways to remove pollution from the air. It is a very difficult problem, and it can be very costly (and you cannot cause a new problem while fixing another). For example, scientists are trying to figure out ways to store CO2 underground, but it takes a lot of energy to do so, and using energy also means making more CO2! So, this is one of those problems where there are many good ideas that need to be developed further. In the case of pollution, chemistry and thermodynamics are really important subjects. Maybe you'll grow up to be a scientist and help address some of these very important problems!
Hope this helps,
As always, the simplest (and often, cheapest) way to reduce the amount of pollution in the air is to put less of it there in the first place. Minimizing our emission of pollution is always the first step in addressing this issue.
That being said, there are ways to eliminate some of the pollutants already in the air. The most commonly considered pollutant nowadays is carbon dioxide, the major greenhouse gas that is affecting global climate change. Carbon dioxide can be removed from the atmosphere most easily using nature's own process - photosynthesis, where plants convert sunlight, water, and carbon dioxide into oxygen and glucose. Replanting forests and limiting the destruction of current forests would help significantly, as would protecting marine ecosystems. Plants may also be able to 'filter' the atmosphere of other harmful pollutants, though those details are more complex.
In the absence of such natural approaches, it is reasonable to ask whether it is possible to remove pollutants through artificial means. Returning to carbon dioxide, there are a number of experimental technologies being investigated called 'carbon capture and storage', where carbon dioxide is moved out of the air and stored somewhere it will not be harmful, such as underground. These techniques tend to focus on eliminating pollution about to be put into the atmosphere rather than cleaning pollution already existing in the atmosphere. However, some more speculative ideas also suggest that pollution might be filtered out of the atmosphere directly.
Other approaches involve the use of specially engineered micro-organisms to remove harmful molecules and particles from the atmosphere. This technique, called 'bioremediation' is also still experimental but may be important in removing some very harmful pollutants.
Unfortunately, all of these technologies and approaches are slow, expensive, and in many cases unproven. A much simpler approach would be to limit our emissions of pollutants in the first place. This has worked successfully for some types of very harmful pollutants - for example, chlorofluorocarbons (CFCs) are an ozone-destroying greenhouse gas that has been largely eliminated from use because of its harmful pollution. Emissions of soot particles and other pollutants like mercury from coal-burning power plants have been dramatically reduced by the use of clever technologies. Although the biggest concern for air pollution today, carbon dioxide, has not been effectively addressed, scientists and politicians continue to try to find a way to reduce our emissions without significantly affecting the way we live our lives. It is an important challenge, but one we have not yet solved.
Shimon Unterman Ph.D.
Scrubbing pollution from the air that is already present is a HUGE task! There is a way, but unfortunately it takes energy (and pollution) to do it. A lot of energy.
Coulson and Richardson came up with an air scrubber called the "Coulson Precipitator". It works well with air pollution coming out of a factory that is making energy. The Precipitator uses some of the energy of the factory to energize the scrubber. Those pollutants are sanitized or reused or buried.
Your idea is a great idea, but we must first think of a way to make clean energy, truly clean to power the Coulson Precipitator to scrub our air. Then we must make thousands of them so that we can clean up our atmosphere.
This is a very big job. Right now, it is so expensive we do not have a way to do it and be able to live our lives.
With scientists like you growing up with ideas like yours - you will lead us toward a way to do just that!
Thank you! Peter E. Hughes, Ph.D.,
Good question, Carrie. It would be neat to be able to do just that.
People are working on ways to remove carbon dioxide from the atmosphere and store it underground as a chemical. But that is a really big job since there is so much air to treat and, it may cost too much to do.
Otherwise, I cannot think of any people trying to remove other pollutants from the air and water that are already in there. Part of the problem is that there is so much air in the atmosphere and so much water on earth.
That is why you see people trying to pollute less - it's a lot easier and cheaper to do.
Hope this helps.
Past Questions of the Week
Update: June 2012