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Reduction of air pollutants

Methods to reduce air pollutants include regulatory practices, conservation practices, and alternative fuels. Created by Khan Academy.

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  • male robot hal style avatar for user KEVIN
    OK, I'm totally on board with all the points made in the lesson. But aren't these band-aids on the larger problem? And, not to make this a political issue, but aren't political stances, especially in the US, a big part of why we can't come to a consensus? I'm sure there are many on the radical right, also known as Republicans, who are at this moment demonizing the activities at the Glasgow conference (11/2021) and demonizing activists such as Greta Thunberg. How will we ever confront the climate crisis when at least 50% of the population is anti-science and follows the antics of buffoons and conspiracy theorists? I will do my part but I do not think that riding bicycles and driving electric cars is enough. There has to be a paradigm shift across the population as a whole and I do not see that happening in time to stall the catastrophe that is out there.
    (9 votes)
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    • female robot grace style avatar for user SciBlazeMaker
      I think climate change is urgent, but people just don't care. Like Greta Thunberg says in her book No One Is Too Small To Make A Difference , "There are no grey areas when it comes to survival." and that politicians do not have environmentalism in mind. We need to take action now because we have to "unite behind the science".
      (7 votes)
  • leaf red style avatar for user Leyard
    I understand factories and other manufacturing plants, produce a lot of exhaust and air pollutant. Is there any way we could potentially reduce this? Or find more natural ways to create electricity instead of using oil and polluting our air? Another question, that is sort of off topic but it still relates to the problem at hand, pollution. I am not incredibly educated with how we deal with our landfills, but I do know that they do get dumped into our rivers- certainly not as much but still happening, or our sea, or burned. Are there any ways we know of to dispose of our garbage without harming ecosystems and land?
    (3 votes)
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Video transcript

- [Instructor] Hey there, friends. Today, we're gonna learn about air pollution. And to start off, we're going back in time to the small town of Donora, Pennsylvania, in October of 1948. (pensive harp music) Walking into this small industrial town, you can immediately sense that something is wrong. It's the middle of the day, but there's a thick yellowish smog everywhere, enveloping everything and even blocking out the sun. It's so dark that streetlights are on during the daytime. It stings your eyes and it's hard, even painful to breathe. What we're experiencing is the Donora Death Fog, one of the worst air pollution disasters in the United States. Donora was an industrial town full of steel plants and mills which released toxic emissions, such as hydrogen fluoride and sulfur dioxide when processing steel and other metals. Normally, these poisonous gases would disperse into the atmosphere. But this time, there was a temperature inversion, which caused a blanket of warm air to cover a layer of colder air near the surface and ride over Donora. Consequently, the toxic emissions were essentially trapped under the warm air. Over the course of several days from October 26th to October 31st, these toxic emissions had accumulated so much that half of the 14,000 people living in Donora suffered from respiratory problems and 20 people died. Relief only came when the steel mills were shut down and a rainstorm alleviated the smog. But following the deadly Donora smog, the public began to realize just how dangerous and life-threatening air pollution could be, and citizens demanded change. Donora became a turning point in US history and was a start of the clean air movement. The Air Pollution Control Act of 1955 was the first piece of US federal legislation involving air pollution and provided funds for research about air pollution. Then, in 1963, the Clean Air Act was passed, the first federal legislation to control air pollution, and later expanded in 1970, which resulted in the creation of the US Environmental Protection Agency, the EPA, to develop and enforce regulations to protect the general public from exposure to major outdoor air pollutants. The Clean Air Act was expanded in 1977 and again in 1990. And throughout its nearly-60-year history, our air quality has drastically improved and pollutants have dropped sharply. Since 1990, major air pollutants such as carbon monoxide, nitrogen oxides, sulfur dioxide, and volatile organic compounds have greatly decreased, and that's just since 1990. These four main air pollutants that I highlighted are largely released as emissions from burning fossil fuels, which comes from driving vehicles and operating coal-fired power plants and other industrial facilities. So, as we've started to drive more efficient vehicles and obtain more energy from clean renewable sources, we've decreased the amount of fossil fuels that we use. And in turn, we've reduced emissions from fossil fuels and associated air pollutants. But how does the Clean Air Act work exactly? How do we clean the air and limit emissions of harmful pollutants? Clean Air Act regulations implemented by the EPA have led to new technologies that help to limit emissions and remove pollutants from the air. In particular, many of these technologies help to reduce air pollution from coal-burning power plants and vehicles. Each of these pollution-control technologies functions to remove harmful components out of emissions and release a less harmful substance. In the last decade or so, you've also probably noticed more and more electric vehicles on the road. Improving the fuel economy of vehicles and even using battery-powered electric vehicles can reduce the need to burn as much gasoline, thereby reducing emissions and giving us cleaner air. A good example is the growing demand for hybrid and purely electric vehicles. Here we have a simplified figure that explains the sources of energy for different types of vehicles and their respective emissions. On the left, we have conventional vehicles, which rely on fossil fuels such as gasoline or diesel and, when driven, produce lots of emissions like carbon dioxide and air pollutants. Hybrid and plug-in hybrid vehicles are similar to conventional vehicles in that they have an internal combustion engine, but they also have an electric motor which uses energy stored in batteries. These batteries can be charged by regenerative braking or, in the case of plug-in hybrids, just by using a wall outlet or other charging equipment. In turn, because these hybrid cars are partially fueled by batteries, they produce fewer emissions than a conventional car. Finally, vehicles that rely solely on electricity, known as battery electric vehicles or BEVs, can use an alternative electricity source so that there's no emissions at the source of the electricity. What else can we do to ensure cleaner air? We can reduce our reliance on fossil fuels and instead invest in cleaner renewable resources to generate electricity such as geothermal, wind, and solar. And we can make decisions in our day-to-day lives to reduce or prevent air pollution by using less energy and alternative fuels. For example, walking, biking, or using mass transportation can reduce the need to burn fossil fuels. And there are plenty of other ways to reduce our electrical needs; in particular, using more energy-efficient appliances. For example, think of the LED bulb, which uses 75% less energy than incandescent lighting. So, even switching out bulbs in the lights around your house or apartment can make a huge difference. But there's still many other places out there like Donora, and oftentimes folks living in cities with heavy air pollution literally can't afford to leave. There's still much work to be done. In Donora, though, there's the Donora Smog Museum, which has the tagline "Clean air started here." The terrible incident suffered by Donora's community played a huge and pivotal role in opening the eyes of Americans to the hazards of air pollution and spurred political action that's carried forth through today and will continue into the future. Let's all take a deep breath and be glad that we can.