The World Health Organization says that 92 percent of the world's population lives in areas of high air pollution.
Experts say much of that pollution comes from vehicles fueled by diesel. Many cities in Europe have called for ending the production of diesel cars. They hope to replace them with electric vehicles as battery life for those vehicles improves.
London is one of the most heavily polluted cities in Europe. Levels of harmful gases in the city are regularly higher than limits set by the European Union.
Martin Williams, with King's College London, says pedestrians often do not realize how close they are to air pollution sources because they cannot see them.
"One of the difficulties of getting the message across to the public at large these days is that air pollution, although it's a major public health problem, is actually invisible. Not like the smogs of the 1950s and 60s when not only could you see it, you could barely see anything else."
Williams adds that toxic gases from diesel cars have led to public health concerns. He says people across Great Britain have died too early because of the pollution.
"The main problem that you are breathing in are the particulates, the soot largely from diesel exhausts, which is the primary problem as far as public health is concerned. And that's responsible for maybe up to around 30,000 premature deaths across Britain. The other pollutant that's more recently become an issue is nitrogen dioxide, again largely from diesel."
Last year, officials discovered that German carmaker Volkswagen attempted to cheat on emissions tests on its vehicles. The incident became known as ‘diesel-gate.'
Areeba Hamid is with the environmental group Greenpeace. She says that incident is why many in the automobile industry want to produce electric cars.
"It's quite clear that the car industry is feeling the pressure of a public health crisis owing to air pollution in big cities in particular and the aftermath of the diesel-gate' scandal, which is the reason why it's looking to produce new electric models."
At the Paris Motor Show in September, many of the vehicles on display were electric cars. Volkswagen announced it aims to sell two to three million electric vehicles each year by 2025.
Experts say electric cars could offer the answer to air pollution in major cities. They add, however, that the electricity should be created using renewable energy.
I'm Jonathan Evans.
Ingrid was a walker, even in Los Angeles, where a pedestrian is a rare sight.
Any particulate filter eventually clogs, so you have to replace it as breathing becomes difficult.
This is the only zero-emission car on the market.
But these innovations have reduced his use of diesel by only around 25%.
1.Many cities in Europe have called for ending the production of diesel cars.
call for 要求，呼吁
It's a situation that calls for a blend of delicacy and force.
Their occurrence does not call for any change in the present level of pandemic alert.
2.They hope to replace them with electric vehicles as battery life for those vehicles improves.
replace... with... 用……替换……
Soon these equipment will be dismantled since they were erected in 1982 and be replaced with modern ones.
This collaborator must be replaced with a mock object.
有专家表示，很多高浓度污染的来源是柴油车辆造成的 。欧洲很多城市已呼吁停止生产柴油车辆，希望用电动车代替柴油车，因为使用电动车电池的寿命也在不断提升 。
伦敦是欧洲大气污染最严重的城市之一 。通常情况下，城市里有害气体的水平已高于欧盟设定的限制 。
“如今，将这个信息传达给广大民众的困难之一就是：虽然空气污染是一个重要的公共健康问题，但它实际上是看不见的 。它不同于20世纪五六十年代的大雾，因为那时的大雾不仅能看见，而且除了它也什么都看不见” 。
马丁补充说道，来自柴油车辆的有害气体已经导致了很多公众健康问题 。他说英国的很多人由于空气污染而过早死亡 。
“我们吸入空气的主要问题在于颗粒物，它们是柴油车辆尾气中的烟灰，也是公共健康方面的主要问题 。颗粒物可能是英国3万名早逝案例的罪魁祸首 。另一个新近成为污染物的例子是二氧化氮，它的主要来源也是柴油车辆” 。
去年，工作人员发现，德国车企大众企图在车辆排放上蒙混过关 。此次事件被人们成为“柴油门” 。
哈米德是环保组织绿色和平组织的工作人员 。她表示，此次柴油门事件说明了很多车企想生产电动车的原因 。
“很明显，车企感受到了公众健康危机的压力，这是由大城市的空气污染造成的 。这种压力在柴油门丑闻后尤为明显 。这也是车企行业开始转而生产电动类型车辆的原因” 。
在9月的巴黎车展上，很多展示的车辆都是电动车 。大众宣布其目标是在2025年之前销售200到300万辆电动车 。
有专家表示，电动车是解决大城市空气污染的正解 。他们还补充说道，不过，电能应该是通过可再生能源获得的 。