0:00:02 > 0:00:05Welcome to Bang, where we bring you the science behind the headlines
0:00:05 > 0:00:07and tackle the issues that have real impact on your lives.
0:00:07 > 0:00:11Despite the weather here today, spring will soon be in the air
0:00:11 > 0:00:13but what else will be?
0:00:13 > 0:00:16The data from air-monitoring systems like this one
0:00:16 > 0:00:20high above the congested streets of London is not looking good.
0:00:20 > 0:00:25In fact, some experts have ranked air pollution as second only
0:00:25 > 0:00:28to smoking in terms of public health risks.
0:00:28 > 0:00:31In February of this year, the London Mayor's Office
0:00:31 > 0:00:34went as far as broaching the subject of keeping some children
0:00:34 > 0:00:38off playgrounds on days when air pollution is at its highest.
0:00:38 > 0:00:41And just last week, yet another report linked air pollution
0:00:41 > 0:00:44to heart disease and strokes.
0:00:44 > 0:00:48The reality is that our air quality is seriously affecting our health.
0:00:48 > 0:00:50So, with allergies on the rise
0:00:50 > 0:00:54and poor air quality being blamed for everything from cancer
0:00:54 > 0:00:58to asthma, tonight we take a look at what we're breathing in.
0:01:00 > 0:01:04Coming up, I find out how much pollution ordinary commuters breathe in.
0:01:04 > 0:01:07It certainly opened our eyes to the level of pollution we're taking in.
0:01:07 > 0:01:11Maggie discovers the almost instant effect of toxic air
0:01:11 > 0:01:13on our blood system.
0:01:13 > 0:01:15These particles get deep down into the lung
0:01:15 > 0:01:19and may actually be able to cross into the bloodstream.
0:01:19 > 0:01:24And Jem reveals why diesel engines produce more soot than petrol cars.
0:01:24 > 0:01:26As soon as there's a spark...
0:01:26 > 0:01:28LID CLATTERS
0:01:29 > 0:01:33..you, um, get quite a nice explosion.
0:01:35 > 0:01:38That's air pollution on Bang Goes The Theory.
0:01:41 > 0:01:45In December 1952, thousands of Londoners were killed
0:01:45 > 0:01:49in one of the worst air pollution incidents in British history.
0:01:50 > 0:01:54These pea-soupers were a common occurrence in 1950s,
0:01:54 > 0:01:58regularly covering London in a thick blanket of smog.
0:02:00 > 0:02:03Well, they don't make pollution like they used to.
0:02:03 > 0:02:06But while the air certainly looks a lot cleaner nowadays,
0:02:06 > 0:02:08and the visible effects of pollution have disappeared,
0:02:08 > 0:02:11unfortunately the health dangers haven't.
0:02:11 > 0:02:14A recent Government study estimated that, in Britain,
0:02:14 > 0:02:20air pollution causes the early deaths of 29,000 people every year.
0:02:27 > 0:02:32But I'm not so sure people appreciate just how serious it is.
0:02:32 > 0:02:35I want to see if members of the public can work out where
0:02:35 > 0:02:39air pollution sits in relation to some more familiar killers.
0:02:39 > 0:02:43- Would you be interested in a quick game of death?- Yes.
0:02:43 > 0:02:45All right, then,
0:02:45 > 0:02:50so this is our scale from 0 deaths per year to 100,000, in the UK.
0:02:50 > 0:02:54I've got obesity, car accidents, cigarettes and air pollution.
0:02:54 > 0:02:57- Where do you think these four sit on this scale?- Um...
0:02:57 > 0:03:01I think that car accidents are right at the top,
0:03:01 > 0:03:04because a lot of people don't take care on the roads.
0:03:04 > 0:03:06Obesity?
0:03:06 > 0:03:09- Where do you reckon it would be? - Somewhere like there.
0:03:09 > 0:03:12Air pollution - we're not thinking many, are we?
0:03:12 > 0:03:14- Oops!- It's all right.
0:03:14 > 0:03:19- Air pollution would be quite low, wouldn't it?- Air pollution...
0:03:19 > 0:03:22It'll probably end up being air pollution is number one.
0:03:22 > 0:03:25I'll put this down here. We'll probably get it totally whack.
0:03:25 > 0:03:28Interesting! So you've got cigarette as the worst thing,
0:03:28 > 0:03:32the most dangerous, then obesity, car accidents, air pollution.
0:03:32 > 0:03:36You were spot on with cigarettes. The next one is air pollution.
0:03:36 > 0:03:40- Air pollution?- More than three times as many deaths due to air pollution
0:03:40 > 0:03:42in this country than obesity.
0:03:42 > 0:03:46- Really?- Wow. - Are you surprised?- Yeah, I was.
0:03:46 > 0:03:49I thought air pollution didn't kill people that much.
0:03:49 > 0:03:52- You just breathe in what you breathe.- Yeah.
0:03:55 > 0:03:58So, what is it in our air that's so dangerous?
0:03:58 > 0:04:03To find out, I'm looking at a sample of typical British city air.
0:04:03 > 0:04:09In this box I've got exactly 1 cubic metre of standard London air.
0:04:10 > 0:04:13Now, most of it is nitrogen and oxygen, but there is
0:04:13 > 0:04:16some pollution in there.
0:04:16 > 0:04:20These coloured balls represent the volume of each of them.
0:04:20 > 0:04:25At 200 parts per billion, there's just this much carbon monoxide,
0:04:25 > 0:04:27a highly toxic gas.
0:04:28 > 0:04:32There are 20 parts per billion of ozone.
0:04:32 > 0:04:35Up there, it does as a real favour, blocking UV light.
0:04:35 > 0:04:38Down here, it's quite an irritant.
0:04:39 > 0:04:43There's just a tiny scrape of pollen, not strictly a pollutant
0:04:43 > 0:04:47but enough to make life miserable for hay fever sufferers.
0:04:48 > 0:04:52None of these are good news, but across the UK,
0:04:52 > 0:04:54they are usually below safety levels.
0:04:54 > 0:04:58It's my final two pollutants that scientists are most worried about.
0:04:58 > 0:05:02First, is a gas - nitrogen dioxide -
0:05:02 > 0:05:06that tends to be given off by vehicle exhausts.
0:05:06 > 0:05:09It's an irritant, it's a pollutant,
0:05:09 > 0:05:14and in there, there is just that much.
0:05:16 > 0:05:18And finally, particulate matter -
0:05:18 > 0:05:22basically soot articles to you and me.
0:05:22 > 0:05:26About half of one of these tiny balls - I'll drop that in.
0:05:28 > 0:05:30So, that's it. The air that we breathe.
0:05:30 > 0:05:32It doesn't look too bad, but the thing is,
0:05:32 > 0:05:36those tiny amounts can really have quite a large effect
0:05:36 > 0:05:39AND you've got to bear in mind that, on average,
0:05:39 > 0:05:43each person breathes in 14 of these cubic metres,
0:05:43 > 0:05:46that's 14,000 litres of London air a day,
0:05:46 > 0:05:50and over a week, a month, a lifetime,
0:05:50 > 0:05:53those tiny amounts really start stacking up.
0:05:58 > 0:06:03Thankfully, few people breathe air this polluted all the time.
0:06:05 > 0:06:07But wherever we live,
0:06:07 > 0:06:11lots of us do breathe it in short bursts every day,
0:06:11 > 0:06:14during rush-hour, when we're all on the move and just
0:06:14 > 0:06:16when pollution levels are at their highest.
0:06:16 > 0:06:20Is that enough to worry about? To find out,
0:06:20 > 0:06:23I've come to Birmingham, one of Britain's most congested cities,
0:06:23 > 0:06:26and I'm going to try and quantify just how much polluted air
0:06:26 > 0:06:28the average person takes in on their daily commute.
0:06:28 > 0:06:32Helping me is pollution expert Dr Saborit
0:06:32 > 0:06:35from Birmingham University.
0:06:35 > 0:06:39She carries out research into personal pollution exposure
0:06:39 > 0:06:43and is kitting me out with the very latest in mobile pollution monitors.
0:06:43 > 0:06:47So, tell me about these monitors. What exactly are they measuring?
0:06:47 > 0:06:51These monitors are measuring tiny dust particles
0:06:51 > 0:06:55that are floating in the air and that are lower than 2.5 microns, and just
0:06:55 > 0:06:59to give you an idea, the naked eye only can see 40 microns,
0:06:59 > 0:07:03that's the minimum we can see, so those are more than ten times
0:07:03 > 0:07:05smaller than what we can see with our eyes.
0:07:05 > 0:07:08OK, so we've got three of these air pollution monitors
0:07:08 > 0:07:11all charged up and ready to go, and we going to put them to the test
0:07:11 > 0:07:16on three computers that are braving the rush-hour traffic into Birmingham.
0:07:18 > 0:07:22Gary, James and John all live in Sutton Coldfield
0:07:22 > 0:07:25and travel into work at their Birmingham-based company
0:07:25 > 0:07:28every day, but they get there in very different ways.
0:07:29 > 0:07:33- Gary drives his car...- To me, it's the easiest form of commute.
0:07:33 > 0:07:36I have a car parking space in Birmingham and, therefore,
0:07:36 > 0:07:41- it's relatively inexpensive for me. - ..James uses pedal power...
0:07:41 > 0:07:45It's much more healthy and I get to experience the outdoors,
0:07:45 > 0:07:47and it's typically quicker, sometimes,
0:07:47 > 0:07:50than being stuck in the traffic in the car.
0:07:50 > 0:07:52..and John takes the train.
0:07:52 > 0:07:55The train is the quickest form of transport into Birmingham,
0:07:55 > 0:07:57and the cheapest, so that's how I travel.
0:07:57 > 0:07:59I've given each of them a monitor,
0:07:59 > 0:08:04and we're going to see just what they're taking in on their morning commute.
0:08:23 > 0:08:25- So, how did you guys get on? - OK.- Good.
0:08:25 > 0:08:28- Who got here first, by the way?- I did.- On the bike. No surprise there.
0:08:28 > 0:08:33- Monitors, please. ..Ah, stuck in traffic?- I was. Apologies.
0:08:33 > 0:08:39No worries. Thank you very much, chaps. OK, time to get these analysed.
0:08:39 > 0:08:43The results are in and it's time to show our commuters how much
0:08:43 > 0:08:47particle pollution they face every day.
0:08:47 > 0:08:52I want to show you the concentration of particulate matter that you were exposed to this morning.
0:08:53 > 0:08:55John's train journey was the cleanest,
0:08:55 > 0:08:58while cyclist James faced the highest level of pollution.
0:08:58 > 0:09:01Does it make you panic a little bit to see that you are
0:09:01 > 0:09:03so much higher than the other guys?
0:09:03 > 0:09:06I would like to think that the benefits from cycling to work
0:09:06 > 0:09:11probably outweigh the dangers of inhaling that much particulate matter.
0:09:11 > 0:09:15As a cyclist, James is breathing in at a much faster rate,
0:09:15 > 0:09:18so he is taking in greater volumes of this air.
0:09:18 > 0:09:25What can James do to improve his exposure to these pollutions when he is cycling then?
0:09:25 > 0:09:27What he could do, and it's a really easy measure,
0:09:27 > 0:09:30it's cycling in canals or green areas.
0:09:30 > 0:09:34That could reduce his exposure by 30% to 60%.
0:09:34 > 0:09:39That will make a big difference. Now, Gary has the protection of the car.
0:09:39 > 0:09:43But the pollutants are still getting in.
0:09:43 > 0:09:46How can Gary improve this exposure?
0:09:46 > 0:09:50What he can do is try to avoid the peak hour traffic
0:09:50 > 0:09:57so if he goes one hour later or one hour before, he can drop it by 15% to 30%.
0:09:57 > 0:10:02And also another measure he can do is using the air conditioning.
0:10:02 > 0:10:05I didn't have the air conditioning on during the journey this morning.
0:10:05 > 0:10:08That will make a difference, because then you are filtrating the air
0:10:08 > 0:10:11that is coming in to the car so that would give you extra protection.
0:10:11 > 0:10:14- How much more protection would he get?- Between 30% and 50%.
0:10:14 > 0:10:16- Oh, really?- Oh, wow.
0:10:16 > 0:10:19The huge irony is that by turning on the air con to protect yourself
0:10:19 > 0:10:22you are producing more fumes, which means that these fellows
0:10:22 > 0:10:25- will be exposed to more pollutants.- Sorry, guys!
0:10:25 > 0:10:27Simple as that!
0:10:27 > 0:10:31Dr Saborit has also calculated the average level
0:10:31 > 0:10:33taken in by our commuters over a whole day
0:10:33 > 0:10:36so we can see how they measure up to global limits.
0:10:36 > 0:10:40This red line here represents the guideline limit of what
0:10:40 > 0:10:43you should be exposed to in 24 hours by the World Health Organisation.
0:10:43 > 0:10:47This is where you all stand. What do you think about these?
0:10:47 > 0:10:49I suppose the issue is that the red line,
0:10:49 > 0:10:53that'll be a global line. And you take places like China and Brazil
0:10:53 > 0:10:56etc where pollution is that much worse,
0:10:56 > 0:10:58being in Birmingham in the UK,
0:10:58 > 0:11:02it is slightly concerning that it is so close to that red line.
0:11:03 > 0:11:07It is clear that many people in Britain could easily be facing
0:11:07 > 0:11:10dangerous levels of pollution on a regular basis.
0:11:10 > 0:11:14But do we know what that could actually do to our health?
0:11:14 > 0:11:18I was just wondering whether you are the least bit concerned about air pollution.
0:11:18 > 0:11:20I am worried about the effect it has on my health,
0:11:20 > 0:11:22because I suffer from asthma.
0:11:22 > 0:11:25Because you can't see it, people think it's not there and they don't pay attention to it.
0:11:25 > 0:11:28Particularly for children and young adults, growing up
0:11:28 > 0:11:31in an inner-city with the air pollution, it is not good for their health.
0:11:31 > 0:11:36No-one seems to tell you whether or not the air that you are breathing is perfectly safe or not.
0:11:36 > 0:11:38People are right to be concerned.
0:11:38 > 0:11:42Air pollution has been linked to a number of serious health issues
0:11:42 > 0:11:46such as cancer, reduced lung capacity and low birthweight babies.
0:11:46 > 0:11:51And just this year, new research into asthma has indicated that air
0:11:51 > 0:11:56pollution may not only exacerbate it, it may actually cause it.
0:11:56 > 0:11:59Recently, scientists have become concerned that pollution can
0:11:59 > 0:12:05harm us even more, by getting beyond our lungs and into our blood.
0:12:05 > 0:12:08It is not something that takes years to build up.
0:12:08 > 0:12:11The effects can be seen from the moment you are exposed.
0:12:13 > 0:12:17This is Lucy, she has lived all her life year in rural Suffolk.
0:12:18 > 0:12:23Pollution levels in this region are well below the national average.
0:12:23 > 0:12:29But aspiring actress Lucy is now off to seek fame and fortune in the big smoke. London.
0:12:31 > 0:12:34Have you got any concerns about the move?
0:12:34 > 0:12:38I think the faster pace of life is a bit scary. Things like pollution.
0:12:38 > 0:12:41Sometimes when I come back from London
0:12:41 > 0:12:45and blow my nose and it is black, you start to think, blimey,
0:12:45 > 0:12:47what is actually going inside of my body?
0:12:47 > 0:12:52Lucy's fears about her move to the city are not unfounded.
0:12:52 > 0:12:56Research has shown that 86% of the areas worst affected
0:12:56 > 0:12:59by air pollution in England are in London.
0:13:00 > 0:13:02So, I have enlisted the help of cardiologist
0:13:02 > 0:13:08Dr Jeremy Langrish to find out how Lucy's health will be affected by breathing London air.
0:13:11 > 0:13:14I live in London, I have grown used to all of this.
0:13:14 > 0:13:18But for someone like Lucy who is moving from the country to the city,
0:13:18 > 0:13:22what kind of effects is air pollution likely to have on her health?
0:13:22 > 0:13:25It has been known for some time that air pollution can affect
0:13:25 > 0:13:26the lungs and respiratory system.
0:13:26 > 0:13:29Perhaps more surprising is that it can have
0:13:29 > 0:13:31a dramatic effect on our cardiovascular system as well.
0:13:31 > 0:13:35It is the cardiovascular system that you are particularly interested in.
0:13:35 > 0:13:40That's right. We know from studies that have been done before that exposure to air pollution
0:13:40 > 0:13:43can have quite rapid effects on the cardiovascular system.
0:13:43 > 0:13:46Lucy lives in an area where air pollution is relatively low
0:13:46 > 0:13:51and the levels here in London today are likely to be four or five times higher than what she is used to.
0:13:54 > 0:13:58With some help from Jeremy, Lucy will be our air pollution guinea pig.
0:13:58 > 0:14:02What we are going to do now is take a reading of her cardiovascular system.
0:14:02 > 0:14:06The measurements we are going to do now are essentially a baseline
0:14:06 > 0:14:10measurement when Lucy has been breathing in relatively clean air.
0:14:10 > 0:14:14We will measure the function of the blood vessels themselves
0:14:14 > 0:14:19and we will measure the stiffness of the arteries, which is a marker of cardiovascular health.
0:14:25 > 0:14:28With the test complete, Jeremy now has a good idea
0:14:28 > 0:14:31of how Lucy's cardiovascular system works normally.
0:14:37 > 0:14:41So next, it is time for round two. The pollution round.
0:14:41 > 0:14:43- So do you fancy a bit of window shopping?- Yes!
0:14:43 > 0:14:46We have brought you to Oxford Street
0:14:46 > 0:14:49because as you can see it is absolutely rammed with buses and taxis,
0:14:49 > 0:14:52and so you will be exposed to a lot of pollution.
0:14:52 > 0:14:58- Could you give us about an hour of walking up and down?- Yep. - Off you go.
0:14:58 > 0:15:00And let's see what difference an hour makes.
0:15:13 > 0:15:18After pounding the pavement, it is back to the lab to repeat the tests.
0:15:22 > 0:15:26So you have the detailed results now from both sets of tests. What are they telling you?
0:15:26 > 0:15:31The key result here in terms of a clinical finding is
0:15:31 > 0:15:34the fact that the blood vessel function has become impaired.
0:15:34 > 0:15:38Parallel to that, the arteries appear to be considerably stiffer.
0:15:38 > 0:15:41There is about a 20% increase in the stiffness of the arteries.
0:15:41 > 0:15:44Along with that, there was an increase in stress within the blood vessels.
0:15:44 > 0:15:47All of these things are detrimental to the cardiovascular system.
0:15:47 > 0:15:50- What is your reaction to this? - It is actually quite frightening.
0:15:50 > 0:15:53I never thought that such changes would happen
0:15:53 > 0:15:55so quickly over such a short period of time.
0:15:55 > 0:15:59What exactly is going on to produce these physiological effects?
0:15:59 > 0:16:01There is still a little bit of debate about this.
0:16:01 > 0:16:04But essentially, what is happening is that we are breathing in
0:16:04 > 0:16:07these air pollutants and the pollutant we are interested in
0:16:07 > 0:16:09here is the particles within the air.
0:16:09 > 0:16:12These particles get deep down into the lung where they
0:16:12 > 0:16:14do cause a minor inflammatory reaction within the lung.
0:16:14 > 0:16:17There is some emerging evidence that the particles may be able to
0:16:17 > 0:16:19cross into the blood stream
0:16:19 > 0:16:23and have a direct effect on blood vessels themselves.
0:16:23 > 0:16:27You can imagine that if that dysfunction of the blood vessels continues day on day on day,
0:16:27 > 0:16:31that might increase her risk of heart attacks on the whole.
0:16:33 > 0:16:36You can't live in a city like London without being aware that
0:16:36 > 0:16:38you're exposed to air pollution.
0:16:38 > 0:16:41But I have been absolutely staggered by the immediate effect
0:16:41 > 0:16:44it has on our entire cardiovascular system.
0:16:44 > 0:16:47It has certainly given me food for thought.
0:16:47 > 0:16:51There is no question that the levels of polluted air many of us
0:16:51 > 0:16:53are taking in are a cause for concern,
0:16:53 > 0:16:56and that they are having a noticeable impact on our health.
0:16:58 > 0:17:01But the coal fires and factory smoke that caused the nasty
0:17:01 > 0:17:06smogs of the '50s are mostly gone, thanks to a series of clean air acts.
0:17:06 > 0:17:10And the air today certainly looks much cleaner.
0:17:10 > 0:17:13So what is causing all the pollution today?
0:17:13 > 0:17:17These days, the overriding contributor to our air pollution problems
0:17:17 > 0:17:20is something we can seem to live without. The car.
0:17:22 > 0:17:26Nowadays, most cars on the road fall into one of two categories.
0:17:26 > 0:17:28Either petrol or diesel.
0:17:28 > 0:17:31From the shape of these vehicles on the outside,
0:17:31 > 0:17:33you would not know which is which.
0:17:33 > 0:17:37But on the inside, the engines just don't work in the same way.
0:17:37 > 0:17:43The net result of that is what finally emerges from their exhaust pipes
0:17:43 > 0:17:45is also significantly different.
0:17:45 > 0:17:49All but the very latest diesels give off at least twice the toxic
0:17:49 > 0:17:55nitrogen dioxide and 10 or 20 times the dangerous soot particles that petrol cars do.
0:17:55 > 0:17:58So why is there such a big difference?
0:17:58 > 0:18:02It really comes down to the fuel itself.
0:18:02 > 0:18:04Petrol and diesel.
0:18:04 > 0:18:07They may look the same, and their pumps sit side-by-side
0:18:07 > 0:18:13on the garage forecourt, but there is a significant difference between the two of them.
0:18:13 > 0:18:17To show you, I need a bowl of each and a box of matches.
0:18:19 > 0:18:23By the way, danger alert, do not try this at home.
0:18:31 > 0:18:34Now, petrol is a highly volatile fuel.
0:18:34 > 0:18:38That means it evaporates easily so petrol gas effectively comes up
0:18:38 > 0:18:41and mixes with the air, and so catches fire readily.
0:18:46 > 0:18:50But diesel, made of longer heavier molecules gives off fewer fumes.
0:18:50 > 0:18:52And is actually quite difficult to light.
0:18:55 > 0:18:58Now, because of this big difference in flammability between the two fuels,
0:18:58 > 0:19:01the engines work in fundamentally different ways.
0:19:01 > 0:19:04This is my petrol engine. It's very simple.
0:19:04 > 0:19:09It's just a single cylinder and into it I've got nice-fitting piston that can slide up and down.
0:19:09 > 0:19:12The way the fuel gets introduced into the cylinder,
0:19:12 > 0:19:14because petrol vaporises so readily,
0:19:14 > 0:19:17it actually gets injected into a warm chamber
0:19:17 > 0:19:19just prior to the cylinder.
0:19:21 > 0:19:23And then, as the piston rises,
0:19:23 > 0:19:26it sucks in a mixture of petrol vapours and air.
0:19:27 > 0:19:30And because they are both gases, essentially,
0:19:30 > 0:19:33they can mix very, very intimately.
0:19:33 > 0:19:36So when we introduce a spark...
0:19:39 > 0:19:42You, er, get quite a nice explosion.
0:19:45 > 0:19:49And you see on that explosion it's a very blue flame.
0:19:49 > 0:19:52And that blue means that there's very few soot particles in there.
0:19:52 > 0:19:53It's clean burning.
0:19:56 > 0:19:58Now, a diesel engine has to work differently
0:19:58 > 0:20:02because diesel won't readily vaporise into a gas.
0:20:02 > 0:20:06To make it flammable, it's injected into the air as a kind of fine mist,
0:20:06 > 0:20:10a sort of high-pressure aerosol. Now that...
0:20:13 > 0:20:15..really does catch fire.
0:20:17 > 0:20:22So I'll spray a fine mist of diesel droplets into my cylinder.
0:20:24 > 0:20:25There you go!
0:20:26 > 0:20:29There's a big difference. The flame is bright yellow,
0:20:29 > 0:20:33and that yellowness indicates that there are glowing soot particles in there,
0:20:33 > 0:20:37and you can quite readily see the smoke coming off it, and indeed...
0:20:40 > 0:20:43..the soot. And that's the problem.
0:20:43 > 0:20:46Because in the operation of an engine, there really isn't time
0:20:46 > 0:20:50for all those droplets of liquid to burn completely.
0:20:51 > 0:20:54So what happens is some of it just gets reduced down
0:20:54 > 0:20:57to particles of carbon - soot.
0:20:59 > 0:21:03And that means that the exhaust system of a diesel engine has a bigger job to do.
0:21:06 > 0:21:11In the last ten years, filters to catch the soot have been introduced to diesel exhausts,
0:21:11 > 0:21:13but they can't catch everything,
0:21:13 > 0:21:17especially those tiny, invisible particles.
0:21:17 > 0:21:22To see how much gets through, I've invited along air monitoring expert, Steve Hoskin.
0:21:23 > 0:21:25I've revved the vehicles,
0:21:25 > 0:21:28and Steve has been measuring what's coming out of the exhaust pipes.
0:21:28 > 0:21:29What's the news?
0:21:29 > 0:21:31OK, so, this vehicle, diesel vehicle,
0:21:31 > 0:21:35is fitted with a particulate trap, but despite that, it still emits
0:21:35 > 0:21:37significantly more particles than the petrol engine.
0:21:37 > 0:21:41Our problem in the UK is that we have so many older diesels
0:21:41 > 0:21:44that are 10, 12, even 20 years old,
0:21:44 > 0:21:47because diesel engines go on for a long, long time.
0:21:47 > 0:21:51And the emissions you get are significantly more.
0:21:51 > 0:21:55That is a problem that's here to stay, because after many years,
0:21:55 > 0:21:58promoted as the more efficient and therefore green option,
0:21:58 > 0:22:03we've seen a sixfold increase in the number of diesels on our roads.
0:22:03 > 0:22:06And although the filters fitted today are better than ever,
0:22:06 > 0:22:10some people even take them out to improve performance.
0:22:10 > 0:22:12So what can we do about it?
0:22:13 > 0:22:17In the UK, scientists are trying out all sorts of schemes
0:22:17 > 0:22:18to clean up the air.
0:22:20 > 0:22:24I've come to Sheffield, known as an industrial powerhouse
0:22:24 > 0:22:28but now at the forefront of Britain's clean air strategy.
0:22:28 > 0:22:32With schemes to encourage you to give up your car for the day
0:22:32 > 0:22:35or to take up cycling, and with the introduction of a whole
0:22:35 > 0:22:38fleet of hybrid buses and electric cars...
0:22:38 > 0:22:42Let's just get this plugged in. There we are.
0:22:42 > 0:22:47..This is one city that's really determined to clean up its act.
0:22:47 > 0:22:51But while they can help to keep urban air clean, electric cars
0:22:51 > 0:22:55mainly just move the pollution to power stations outside the cities.
0:22:55 > 0:22:58Materials chemist Prof Tony Ryan has been trying
0:22:58 > 0:23:02a novel way to actually mop up pollution from the air.
0:23:04 > 0:23:07We want to turn people into environmental cleanup agents
0:23:07 > 0:23:11by making their clothes active, so as they wander around
0:23:11 > 0:23:13in the sunlight,
0:23:13 > 0:23:16their clothes can repair the damage to the air.
0:23:16 > 0:23:21These jeans are coated with nano particles of titanium dioxide.
0:23:21 > 0:23:24What happens is sunlight comes in so that the photon comes
0:23:24 > 0:23:28whizzing in, it messes with electrons on the surface,
0:23:28 > 0:23:31they split oxygen into two free radicals,
0:23:31 > 0:23:34and they are very, very reactive, they'll react with anything.
0:23:34 > 0:23:38Then there's a chain of reactions that then
0:23:38 > 0:23:43neutralises the nitric oxide from cars and volatile organics, smells.
0:23:43 > 0:23:47So are you suggesting that everyone needs to buy special jeans?
0:23:47 > 0:23:48No, not at all.
0:23:48 > 0:23:52It could be in the washing powder, or it could be a spray-on thing when you're ironing,
0:23:52 > 0:23:55it could be delivered in dry cleaning.
0:23:55 > 0:23:58You know, all of your clothes could get treated.
0:23:58 > 0:24:02You wouldn't know it was there, you can see it, but if enough of us
0:24:02 > 0:24:05did it, there would be a very beneficial effect.
0:24:05 > 0:24:09I know that many people would be thinking - what kind of an impact can a pair of jeans make?
0:24:09 > 0:24:12One pair of jeans makes virtually no impact.
0:24:12 > 0:24:15If the half a million people in Sheffield were wearing
0:24:15 > 0:24:18jeans like this, you'd be able to take out about a ton-and-a-half
0:24:18 > 0:24:20a day of the nitric oxide, and that would
0:24:20 > 0:24:25get us close to the EU limit of 40 micrograms per cubic metre.
0:24:25 > 0:24:28Jeans that clean are really just a concept at the moment,
0:24:28 > 0:24:34but the same technology is already being tested on Sheffield's streets.
0:24:34 > 0:24:37The traffic here is absolutely horrendous.
0:24:37 > 0:24:41You've got a really busy slip road that leads up to the M1,
0:24:41 > 0:24:46nearly 150,000 vehicles a day passing by.
0:24:46 > 0:24:50But this huge wall which is coated in titanium dioxide
0:24:50 > 0:24:52forms part of another trial.
0:24:52 > 0:24:54Behind it there is a school,
0:24:54 > 0:24:57and although it's too early to know whether or not this is making any
0:24:57 > 0:25:00real difference, the theory is that it should be reducing
0:25:00 > 0:25:05the level of air pollution to which the children are being exposed.
0:25:05 > 0:25:10This is just one of the ingenious tactics scientists are trying out.
0:25:10 > 0:25:12But it's hard to know how much difference
0:25:12 > 0:25:16they might really make, and in London a recent experiment with
0:25:16 > 0:25:19sticky roads was deemed a failure.
0:25:19 > 0:25:22All the research suggests that the only real solution is
0:25:22 > 0:25:25to slash car emissions.
0:25:25 > 0:25:28So far, Britain has been slow to face up to this,
0:25:28 > 0:25:31and right now the Supreme Court is considering a case
0:25:31 > 0:25:34calling for EU targets to be enforced here.
0:25:36 > 0:25:41But there are places where they are taking the problem of car emissions much more seriously.
0:25:45 > 0:25:46This is Berlin,
0:25:46 > 0:25:50a city that tops the league tables for improving air quality.
0:25:50 > 0:25:52I haven't been here for ten years,
0:25:52 > 0:25:56but walking around this city I've really noticed a difference.
0:25:56 > 0:25:59There are fewer cars, the ones that are here are so much cleaner.
0:25:59 > 0:26:02More people are walking, more people are using bikes,
0:26:02 > 0:26:04public transport is so much better.
0:26:04 > 0:26:09The whole place feels cleaner, and that's because it is.
0:26:09 > 0:26:13The Berlin government has enforced a total revolution in city transport.
0:26:13 > 0:26:16Here emission zones are far stricter than London's,
0:26:16 > 0:26:19banning older diesels completely.
0:26:19 > 0:26:22Parking is restricted, and bikes are everywhere.
0:26:22 > 0:26:25But it hasn't been easy, and it's taken a man with single-minded
0:26:25 > 0:26:27vision to make it happen.
0:26:27 > 0:26:31Berlin has made some massive changes over the past few years.
0:26:31 > 0:26:35One of the most important ones is environmental zones which
0:26:35 > 0:26:38keeps highly polluting cars and trucks and buses out of the city.
0:26:38 > 0:26:4325% of the cars and trucks produce 75% of the pollution,
0:26:43 > 0:26:45so if you keep them out,
0:26:45 > 0:26:49you reduce dramatically in a very short time the air pollution level.
0:26:49 > 0:26:52You make it sound very easy, but I can't help but think that
0:26:52 > 0:26:54some of those measures must have been very unpopular.
0:26:54 > 0:26:59The question is, to whom belongs the city? To cars or to people?
0:26:59 > 0:27:02In my opinion it's a clear answer - it should be the people.
0:27:02 > 0:27:05I think you probably alerted people to the statistics, because
0:27:05 > 0:27:09I think many people don't understand the effect of air pollution.
0:27:09 > 0:27:11Of course it's important to tell people
0:27:11 > 0:27:1460,000 people in Germany every year is killed by air pollution,
0:27:14 > 0:27:18which is a dramatic number. We can save people's lives.
0:27:18 > 0:27:22We have saved in the last four years 500 people's life per year.
0:27:22 > 0:27:24This is an impressive number.
0:27:24 > 0:27:28To Axel, pollution is something that just can't be ignored.
0:27:28 > 0:27:33It's not a nuisance, it's killing people. It's a silent killing.
0:27:33 > 0:27:35As a result of the cleanup, air pollution in Berlin
0:27:35 > 0:27:39has fallen dramatically, and most importantly,
0:27:39 > 0:27:43diesel soot has dropped by over 60% in four years.
0:27:44 > 0:27:48Berlin offers a vision for how our most polluted cities could look
0:27:48 > 0:27:52in the future if we make the right kind of changes.
0:27:52 > 0:27:54In Britain we've begun to wake up to the problem,
0:27:54 > 0:27:57but many of the measures we introduce are piecemeal,
0:27:57 > 0:28:01whereas here they have gone for a far more comprehensive approach.
0:28:01 > 0:28:04There's no doubt that many of the policies were
0:28:04 > 0:28:06deeply unpopular in Berlin when they were first introduced,
0:28:06 > 0:28:11but now you've got a city where everyone is benefiting.
0:28:11 > 0:28:14I really had no idea how big this problem was,
0:28:14 > 0:28:17and you know, if we want to be serious about tackling air pollution
0:28:17 > 0:28:21and improve our health as a result, we've got to make some drastic
0:28:21 > 0:28:25decisions, and that means fewer cars and cleaner cars.
0:28:25 > 0:28:28And it's all too easy for things that we can't see to just
0:28:28 > 0:28:31slip off our agenda, but it's time we all cleared the air.
0:28:31 > 0:28:35And that's it, not only for tonight, but the whole series.
0:28:35 > 0:28:37- So from all of us, good night.- Bye.
0:28:39 > 0:28:42Visit the website at bbc.co.uk/bang
0:28:42 > 0:28:46for an exclusive film about pollution and sunsets.
0:28:46 > 0:28:49And for more information on air monitoring,
0:28:49 > 0:28:51follow the links to the Open University.
0:28:56 > 0:28:59Subtitles by Red Bee Media Ltd