1.3 减少空气污染
Section outline
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What does a catalytic converter do anyway?
::催化转换器到底是做什么的?In the days before catalytic converters, cars spewed lots of smoke. Laws governing emissions have helped to clean up the air.
::在催化转换器前的几天里,汽车排出了大量烟雾,排放法有助于清除空气。The Clean Air Act
::《清洁空气法》The Clean Air Act of 1970 and the amendments since then have done a great job in requiring people to clean up the air over the United States. Emissions of the six major pollutants regulated by the Clean Air Act — carbon monoxide, lead, nitrous oxides, ozone, sulfur dioxide, and particulates — have decreased by more than 50%. Cars, power plants, and factories individually release less pollution than they did in the mid-20th century. But there are many more cars, power plants, and factories. Many pollutants are still being released and some substances have been found to be pollutants that were not known to be pollutants in the past. There is still much work to be done to continue to clean up the air.
::1970年的《清洁空气法》以及此后的各项修正案在要求人们在美国各地清洁空气方面做了出色的工作。《清洁空气法》所管制的六大污染物——一氧化碳、铅、一氧化二氮、臭氧、二氧化硫和微粒——的排放量已经下降了50%以上。汽车、发电厂和工厂的个别排放污染比20世纪中叶要少。但还有更多的汽车、发电厂和工厂。许多污染物仍然在释放,有些物质是污染物,过去并不知道是污染物。要继续清理空气,还有许多工作要做。Reducing Air Pollution from Vehicles
::减少车辆造成的空气污染Reducing air pollution from vehicles can be done in a number of ways.
::减少来自车辆的空气污染可以采取若干方式。-
Breaking down pollutants before they are released into the atmosphere. Motor vehicles emit less pollution than they once did because of
catalytic converters
(
Figure
). Catalytic converters contain a
catalyst
that speeds up chemical reactions and breaks down nitrous oxides, carbon monoxide, and VOCs. Catalytic converters only work when they are hot, so a lot of exhaust escapes as the car is warming up.
::将污染物释放到大气之前就分解出来。机动车的污染比以前少,因为催化转换器(图 ) 。催化转换器含有加速化学反应和分解一氧化二氮、一氧化碳和VOC的催化剂。催化转换器只有在热时才起作用,因此随着汽车变暖,大量排气排出。
Catalytic converters are placed on modern cars in the United States.
::美国现代汽车上安装了催化转换器。-
Making a vehicle more fuel efficient. Lighter, more streamlined vehicles need less energy.
Hybrid vehicles
have an electric motor and a rechargeable battery. The energy that would be lost during braking is funneled into charging the battery, which then can power the car. The internal combustion engine only takes over when power in the battery has run out. Hybrids can reduce auto emissions by 90% or more, but many models do not maximize the possible fuel efficiency of the vehicle.
::使车辆更高效的燃料。 更轻、更精简的车辆需要更少的能量。 混合型车辆有电动发动机和充电电池。 制动过程中损失的能量被输入电池充电中,然后可以给汽车提供动力。 内燃机只有在电池用完时才能接管。 混合型车辆可以将自动排放减少90%或以上,但许多模型不能最大限度地提高车辆的燃料效率。
A plug-in hybrid is plugged into an electricity source when it is not in use, perhaps in a garage, to make sure that the battery is charged. Plug-in hybrids run for a longer time on electricity and so are less polluting than regular hybrids. Plug-in hybrids began to become available in 2010.
::插件混合体在电源不使用时被插入电源,也许在车库,以确保电池充电,插件混合体在电力上运行时间较长,污染程度也比正常混合体低。 插件混合体于2010年开始供应。-
Developing new technologies that do not use fossil fuels. Fueling a car with something other than a liquid organic-based fuel is difficult. A
fuel cell
converts chemical energy into electrical energy. Hydrogen fuel cells harness the energy released when hydrogen and oxygen come together to create water (
Figure
). Fuel cells are extremely efficient and they produce no pollutants. But developing fuel-cell technology has had many problems and no one knows when or if they will become practical.
::开发不使用化石燃料的新技术; 用液体有机燃料以外的燃料为汽车提供燃料是困难的; 燃料电池将化学能源转换为电力; 氢和氧合力产生水时氢燃料电池利用所释放的能源(图 ) ; 燃料电池效率极高,不会产生污染物。 但是,开发燃料电池技术存在许多问题,没有人知道何时或是否实际可行。
A hydrogen fuel-cell car looks like a gasoline-powered car.
::氢燃料电池车看起来像汽油动力车Reducing Industrial Air Pollution
::减少工业空气污染Pollutants are removed from the exhaust streams of power plants and industrial plants before they enter the atmosphere. Particulates can be filtered out, and sulfur and nitric oxides can be broken down by catalysts. Removing these oxides reduces the pollutants that cause acid rain.
::电厂和工业厂的排气流中的污染物在进入大气层之前就会被清除。 分离物可以被过滤出来,硫和氧化氮可以通过催化剂分解。 清除这些氧化物会减少导致酸雨的污染物。Particles are relatively easy to remove from emissions by using motion or electricity to separate particles from the gases. Scrubbers remove particles and waste gases from exhaust using liquids or neutralizing materials ( Figure ). Gases, such as nitrogen oxides, can be broken down at very high temperatures.
::通过使用运动或电力将颗粒与气体分离,粒子相对容易从排放中去除,灌木工人使用液体或中和材料将颗粒和废气从排气中去除(图)。气体,如氧化氮,可以在极高的温度下分解。Scrubbers remove particles and waste gases from exhaust.
::冲洗机从废气中去除颗粒和废气。Gasification
::气化Gasification is a developing technology. In gasification, coal (rarely is another organic material used) is heated to extremely high temperatures to create syngas, which is then filtered. The energy goes on to drive a generator. Syngas releases about 80% less pollution than regular coal plants, and greenhouse gases are also lower. Clean coal plants do not need scrubbers or other pollution control devices. Although the technology is ready, clean coal plants are more expensive to construct and operate. Also, heating the coal to high enough temperatures uses a great deal of energy, so the technology is not energy efficient. In addition, large amounts of the greenhouse gas CO 2 are still released with clean coal technology. Nonetheless, a few of these plants are operating in the United States and around the world.
::煤气化是一种发展中技术。在气化中,煤炭(很少是另外一种使用的有机材料)被加热到极高的温度以产生合成气体,然后过滤。能源继续驱动一个发电机。合成气体释放的污染比普通煤炭厂少80%,温室气体也更少。清洁煤炭厂不需要洗涤器或其他污染控制装置。虽然技术已经成熟,但清洁煤炭厂的建造和运行费用更高。此外,将煤炭加热到足够高的温度需要大量能源,因此技术效率不高。此外,大量温室气体二氧化碳仍然通过清洁煤炭技术释放。尽管如此,这些工厂中有少数在美国和世界各地运作。Ways You Can Reduce Air Pollution
::减少空气污染的方法How can air pollution be reduced? Using less fossil fuel is one way to lessen pollution. Some examples of ways to conserve fossil fuels are:
::如何减少空气污染?使用较少的矿物燃料是减少污染的一种方法。-
Riding a bike or walking instead of driving.
::骑自行车或走路,而不是开车。 -
Taking a bus or carpooling.
::搭公车或搭车。 -
Buying a car that has greater fuel efficiency.
::购买一辆燃料效率更高的汽车。 -
Turning off lights and appliances when they are not in use.
::不使用灯光和器械时关掉灯光和器械。 -
Using energy efficient light bulbs and appliances.
::使用节能灯泡和电器。 -
Buying fewer things that are manufactured using fossil fuels.
::购买较少用化石燃料制造的物品。
All these actions reduce the amount of energy that power plants need to produce.
::所有这些行动都减少了发电厂需要生产的能源量。Developing alternative energy sources is important. What are some of the problems facing wider adoption of alternative energy sources?
::开发替代能源很重要,哪些问题是更广泛地采用替代能源所面临的一些问题?-
The technologies for several sources of alternative energy, including solar and wind, are still being developed.
::包括太阳能和风能在内的多种替代能源的技术仍在开发中。 -
Solar and wind are still expensive relative to using fossil fuels. The technology needs to advance so that the price falls.
::与使用化石燃料相比,太阳能和风能仍然昂贵。 技术需要进步,以降低价格。 -
Some areas get low amounts of sunlight and are not suited for solar. Others do not have much wind. It is important that regions develop what best suits them. While the desert Southwest will need to develop solar, the Great Plains can use wind energy as its energy source. Perhaps some locations will rely on nuclear power plants, although current nuclear power plants have major problems with safety and waste disposal.
::有些地区日光量低,不适合太阳能,另一些地区没有太多风,重要的是,地区要发展最适合它们的东西。 虽然西南沙漠需要发展太阳能,但大平原可以使用风能作为能源。 也许有些地方会依赖核电站,尽管目前的核电站在安全和废物处理方面存在重大问题。
Sometimes technological approaches are what is needed.
::有时需要的是技术方法。National Geographic videos exploring energy conservation are found in Environment Videos, Energy:
::探索节能的国家地理录像见环境录像,能源:-
Alternative Energy
::替代能源 -
Fuel Cells
::燃料电池 -
Solar Power
::太阳能发电
What you can do to your home to help reduce energy use:
::为减少能源使用,您可以对家里做什么:A very simple thing you can do to conserve energy is discussed in “This Bulb”:
::节能方面你可以做的非常简单的事情在“这个批量”中讨论:Summary
::摘要-
Catalytic converters break down some pollutants, but only when they are hot.
::催化转换器分解了一些污染物,但只有在热时才分解。 -
Hybrid vehicles use the energy that is usually wasted as a car slows to charge a battery that then powers the car.
::混合车辆使用通常浪费的能量,因为汽车在向电池充电时会放慢速度,然后为汽车提供动力。 -
Different types of clean energy can be developed for different locations, such as solar for the desert southwest and wind for coastal regions.
::可为不同地点开发不同类型的清洁能源,例如西南沙漠的太阳能和沿海地区的风能。
Practice
::实践实践实践1. What is a hybrid car a hybrid of?
::1. 混合型汽车是何种混合型汽车?2. Why are hybrids efficient?
::2. 为什么混合体效率高?3. What is the problem with running a car that was just battery powered?
::3. 开着一辆只是用电池充电的汽车有什么问题?4. What is the disadvantage of using batteries?
::4. 使用电池有什么缺点?5. What is the advantage of hybrids over only electric cars?
::5. 混合体对电动汽车有何好处?Review
::回顾1. How do fuel cells work, what are their advantages, and why are they not used in every vehicle?
::1. 燃料电池如何运作,其优势是什么,为什么没有在每一辆车中使用?2. What is gasification technology and what role could it play in reducing air pollution?
::2. 气体化技术是什么,在减少空气污染方面能发挥什么作用?3. What can you do to reduce the amount of air pollution you produce?
::3. 你能做些什么来减少你造成的空气污染?Video on What can you do
::有关你能做什么的视频视频Watch the video at:
::观看影片在: -
Breaking down pollutants before they are released into the atmosphere. Motor vehicles emit less pollution than they once did because of
catalytic converters
(
Figure
). Catalytic converters contain a
catalyst
that speeds up chemical reactions and breaks down nitrous oxides, carbon monoxide, and VOCs. Catalytic converters only work when they are hot, so a lot of exhaust escapes as the car is warming up.
