Episode 8 Bang Goes the Theory

Welcome to Bang, where we bring you the science behind the headlines

and tackle the issues that have real impact on your lives.

Despite the weather here today, spring will soon be in the air

but what else will be?

The data from air-monitoring systems like this one

high above the congested streets of London is not looking good.

In fact, some experts have ranked air pollution as second only

to smoking in terms of public health risks.

In February of this year, the London Mayor's Office

went as far as broaching the subject of keeping some children

off playgrounds on days when air pollution is at its highest.

And just last week, yet another report linked air pollution

to heart disease and strokes.

The reality is that our air quality is seriously affecting our health.

So, with allergies on the rise

and poor air quality being blamed for everything from cancer

to asthma, tonight we take a look at what we're breathing in.

Coming up, I find out how much pollution ordinary commuters breathe in.

It certainly opened our eyes to the level of pollution we're taking in.

Maggie discovers the almost instant effect of toxic air

on our blood system.

These particles get deep down into the lung

and may actually be able to cross into the bloodstream.

And Jem reveals why diesel engines produce more soot than petrol cars.

As soon as there's a spark...

LID CLATTERS

..you, um, get quite a nice explosion.

That's air pollution on Bang Goes The Theory.

In December 1952, thousands of Londoners were killed

in one of the worst air pollution incidents in British history.

These pea-soupers were a common occurrence in 1950s,

regularly covering London in a thick blanket of smog.

Well, they don't make pollution like they used to.

But while the air certainly looks a lot cleaner nowadays,

and the visible effects of pollution have disappeared,

unfortunately the health dangers haven't.

A recent Government study estimated that, in Britain,

air pollution causes the early deaths of 29,000 people every year.

But I'm not so sure people appreciate just how serious it is.

I want to see if members of the public can work out where

air pollution sits in relation to some more familiar killers.

-Would you be interested in a quick game of death?

-Yes.

All right, then,

so this is our scale from 0 deaths per year to 100,000, in the UK.

I've got obesity, car accidents, cigarettes and air pollution.

-Where do you think these four sit on this scale?

-Um...

I think that car accidents are right at the top,

because a lot of people don't take care on the roads.

Obesity?

-Where do you reckon it would be?

-Somewhere like there.

Air pollution - we're not thinking many, are we?

-Oops!

-It's all right.

-Air pollution would be quite low, wouldn't it?

-Air pollution...

It'll probably end up being air pollution is number one.

I'll put this down here. We'll probably get it totally whack.

Interesting! So you've got cigarette as the worst thing,

the most dangerous, then obesity, car accidents, air pollution.

You were spot on with cigarettes. The next one is air pollution.

-Air pollution?

-More than three times as many deaths due to air pollution

in this country than obesity.

-Really?

-Wow.

-Are you surprised?

-Yeah, I was.

I thought air pollution didn't kill people that much.

-You just breathe in what you breathe.

-Yeah.

So, what is it in our air that's so dangerous?

To find out, I'm looking at a sample of typical British city air.

In this box I've got exactly 1 cubic metre of standard London air.

Now, most of it is nitrogen and oxygen, but there is

some pollution in there.

These coloured balls represent the volume of each of them.

At 200 parts per billion, there's just this much carbon monoxide,

a highly toxic gas.

There are 20 parts per billion of ozone.

Up there, it does as a real favour, blocking UV light.

Down here, it's quite an irritant.

There's just a tiny scrape of pollen, not strictly a pollutant

but enough to make life miserable for hay fever sufferers.

None of these are good news, but across the UK,

they are usually below safety levels.

It's my final two pollutants that scientists are most worried about.

First, is a gas - nitrogen dioxide -

that tends to be given off by vehicle exhausts.

It's an irritant, it's a pollutant,

and in there, there is just that much.

And finally, particulate matter -

basically soot articles to you and me.

About half of one of these tiny balls - I'll drop that in.

So, that's it. The air that we breathe.

It doesn't look too bad, but the thing is,

those tiny amounts can really have quite a large effect

AND you've got to bear in mind that, on average,

each person breathes in 14 of these cubic metres,

that's 14,000 litres of London air a day,

and over a week, a month, a lifetime,

those tiny amounts really start stacking up.

Thankfully, few people breathe air this polluted all the time.

But wherever we live,

lots of us do breathe it in short bursts every day,

during rush-hour, when we're all on the move and just

when pollution levels are at their highest.

Is that enough to worry about? To find out,

I've come to Birmingham, one of Britain's most congested cities,

and I'm going to try and quantify just how much polluted air

the average person takes in on their daily commute.

Helping me is pollution expert Dr Saborit

from Birmingham University.

She carries out research into personal pollution exposure

and is kitting me out with the very latest in mobile pollution monitors.

So, tell me about these monitors. What exactly are they measuring?

These monitors are measuring tiny dust particles

that are floating in the air and that are lower than 2.5 microns, and just

to give you an idea, the naked eye only can see 40 microns,

that's the minimum we can see, so those are more than ten times

smaller than what we can see with our eyes.

OK, so we've got three of these air pollution monitors

all charged up and ready to go, and we going to put them to the test

on three computers that are braving the rush-hour traffic into Birmingham.

Gary, James and John all live in Sutton Coldfield

and travel into work at their Birmingham-based company

every day, but they get there in very different ways.

-Gary drives his car...

-To me, it's the easiest form of commute.

I have a car parking space in Birmingham and, therefore,

-it's relatively inexpensive for me.

-..James uses pedal power...

It's much more healthy and I get to experience the outdoors,

and it's typically quicker, sometimes,

than being stuck in the traffic in the car.

..and John takes the train.

The train is the quickest form of transport into Birmingham,

and the cheapest, so that's how I travel.

I've given each of them a monitor,

and we're going to see just what they're taking in on their morning commute.

-So, how did you guys get on?

-OK.

-Good.

-Who got here first, by the way?

-I did.

-On the bike. No surprise there.

-Monitors, please. ..Ah, stuck in traffic?

-I was. Apologies.

No worries. Thank you very much, chaps. OK, time to get these analysed.

The results are in and it's time to show our commuters how much

particle pollution they face every day.

I want to show you the concentration of particulate matter that you were exposed to this morning.

John's train journey was the cleanest,

while cyclist James faced the highest level of pollution.

Does it make you panic a little bit to see that you are

so much higher than the other guys?

I would like to think that the benefits from cycling to work

probably outweigh the dangers of inhaling that much particulate matter.

As a cyclist, James is breathing in at a much faster rate,

so he is taking in greater volumes of this air.

What can James do to improve his exposure to these pollutions when he is cycling then?

What he could do, and it's a really easy measure,

it's cycling in canals or green areas.

That could reduce his exposure by 30% to 60%.

That will make a big difference. Now, Gary has the protection of the car.

But the pollutants are still getting in.

How can Gary improve this exposure?

What he can do is try to avoid the peak hour traffic

so if he goes one hour later or one hour before, he can drop it by 15% to 30%.

And also another measure he can do is using the air conditioning.

I didn't have the air conditioning on during the journey this morning.

That will make a difference, because then you are filtrating the air

that is coming in to the car so that would give you extra protection.

-How much more protection would he get?

-Between 30% and 50%.

-Oh, really?

-Oh, wow.

The huge irony is that by turning on the air con to protect yourself

you are producing more fumes, which means that these fellows

-will be exposed to more pollutants.

-Sorry, guys!

Simple as that!

Dr Saborit has also calculated the average level

taken in by our commuters over a whole day

so we can see how they measure up to global limits.

This red line here represents the guideline limit of what

you should be exposed to in 24 hours by the World Health Organisation.

This is where you all stand. What do you think about these?

I suppose the issue is that the red line,

that'll be a global line. And you take places like China and Brazil

etc where pollution is that much worse,

being in Birmingham in the UK,

it is slightly concerning that it is so close to that red line.

It is clear that many people in Britain could easily be facing

dangerous levels of pollution on a regular basis.

But do we know what that could actually do to our health?

I was just wondering whether you are the least bit concerned about air pollution.

I am worried about the effect it has on my health,

because I suffer from asthma.

Because you can't see it, people think it's not there and they don't pay attention to it.

Particularly for children and young adults, growing up

in an inner-city with the air pollution, it is not good for their health.

No-one seems to tell you whether or not the air that you are breathing is perfectly safe or not.

People are right to be concerned.

Air pollution has been linked to a number of serious health issues

such as cancer, reduced lung capacity and low birthweight babies.

And just this year, new research into asthma has indicated that air

pollution may not only exacerbate it, it may actually cause it.

Recently, scientists have become concerned that pollution can

harm us even more, by getting beyond our lungs and into our blood.

It is not something that takes years to build up.

The effects can be seen from the moment you are exposed.

This is Lucy, she has lived all her life year in rural Suffolk.

Pollution levels in this region are well below the national average.

But aspiring actress Lucy is now off to seek fame and fortune in the big smoke. London.

Have you got any concerns about the move?

I think the faster pace of life is a bit scary. Things like pollution.

Sometimes when I come back from London

and blow my nose and it is black, you start to think, blimey,

what is actually going inside of my body?

Lucy's fears about her move to the city are not unfounded.

Research has shown that 86% of the areas worst affected

by air pollution in England are in London.

So, I have enlisted the help of cardiologist

Dr Jeremy Langrish to find out how Lucy's health will be affected by breathing London air.

I live in London, I have grown used to all of this.

But for someone like Lucy who is moving from the country to the city,

what kind of effects is air pollution likely to have on her health?

It has been known for some time that air pollution can affect

the lungs and respiratory system.

Perhaps more surprising is that it can have

a dramatic effect on our cardiovascular system as well.

It is the cardiovascular system that you are particularly interested in.

That's right. We know from studies that have been done before that exposure to air pollution

can have quite rapid effects on the cardiovascular system.

Lucy lives in an area where air pollution is relatively low

and the levels here in London today are likely to be four or five times higher than what she is used to.

With some help from Jeremy, Lucy will be our air pollution guinea pig.

What we are going to do now is take a reading of her cardiovascular system.

The measurements we are going to do now are essentially a baseline

measurement when Lucy has been breathing in relatively clean air.

We will measure the function of the blood vessels themselves

and we will measure the stiffness of the arteries, which is a marker of cardiovascular health.

With the test complete, Jeremy now has a good idea

of how Lucy's cardiovascular system works normally.

So next, it is time for round two. The pollution round.

-So do you fancy a bit of window shopping?

-Yes!

We have brought you to Oxford Street

because as you can see it is absolutely rammed with buses and taxis,

and so you will be exposed to a lot of pollution.

-Could you give us about an hour of walking up and down?

-Yep.

-Off you go.

And let's see what difference an hour makes.

After pounding the pavement, it is back to the lab to repeat the tests.

So you have the detailed results now from both sets of tests. What are they telling you?

The key result here in terms of a clinical finding is

the fact that the blood vessel function has become impaired.

Parallel to that, the arteries appear to be considerably stiffer.

There is about a 20% increase in the stiffness of the arteries.

Along with that, there was an increase in stress within the blood vessels.

All of these things are detrimental to the cardiovascular system.

-What is your reaction to this?

-It is actually quite frightening.

I never thought that such changes would happen

so quickly over such a short period of time.

What exactly is going on to produce these physiological effects?

There is still a little bit of debate about this.

But essentially, what is happening is that we are breathing in

these air pollutants and the pollutant we are interested in

here is the particles within the air.

These particles get deep down into the lung where they

do cause a minor inflammatory reaction within the lung.

There is some emerging evidence that the particles may be able to

cross into the blood stream

and have a direct effect on blood vessels themselves.

You can imagine that if that dysfunction of the blood vessels continues day on day on day,

that might increase her risk of heart attacks on the whole.

You can't live in a city like London without being aware that

you're exposed to air pollution.

But I have been absolutely staggered by the immediate effect

it has on our entire cardiovascular system.

It has certainly given me food for thought.

There is no question that the levels of polluted air many of us

are taking in are a cause for concern,

and that they are having a noticeable impact on our health.

But the coal fires and factory smoke that caused the nasty

smogs of the '50s are mostly gone, thanks to a series of clean air acts.

And the air today certainly looks much cleaner.

So what is causing all the pollution today?

These days, the overriding contributor to our air pollution problems

is something we can seem to live without. The car.

Nowadays, most cars on the road fall into one of two categories.

Either petrol or diesel.

From the shape of these vehicles on the outside,

you would not know which is which.

But on the inside, the engines just don't work in the same way.

The net result of that is what finally emerges from their exhaust pipes

is also significantly different.

All but the very latest diesels give off at least twice the toxic

nitrogen dioxide and 10 or 20 times the dangerous soot particles that petrol cars do.

So why is there such a big difference?

It really comes down to the fuel itself.

Petrol and diesel.

They may look the same, and their pumps sit side-by-side

on the garage forecourt, but there is a significant difference between the two of them.

To show you, I need a bowl of each and a box of matches.

By the way, danger alert, do not try this at home.

Now, petrol is a highly volatile fuel.

That means it evaporates easily so petrol gas effectively comes up

and mixes with the air, and so catches fire readily.

But diesel, made of longer heavier molecules gives off fewer fumes.

And is actually quite difficult to light.

Now, because of this big difference in flammability between the two fuels,

the engines work in fundamentally different ways.

This is my petrol engine. It's very simple.

It's just a single cylinder and into it I've got nice-fitting piston that can slide up and down.

The way the fuel gets introduced into the cylinder,

because petrol vaporises so readily,

it actually gets injected into a warm chamber

just prior to the cylinder.

And then, as the piston rises,

it sucks in a mixture of petrol vapours and air.

And because they are both gases, essentially,

they can mix very, very intimately.

So when we introduce a spark...

You, er, get quite a nice explosion.

And you see on that explosion it's a very blue flame.

And that blue means that there's very few soot particles in there.

It's clean burning.

Now, a diesel engine has to work differently

because diesel won't readily vaporise into a gas.

To make it flammable, it's injected into the air as a kind of fine mist,

a sort of high-pressure aerosol. Now that...

..really does catch fire.

So I'll spray a fine mist of diesel droplets into my cylinder.

There you go!

There's a big difference. The flame is bright yellow,

and that yellowness indicates that there are glowing soot particles in there,

and you can quite readily see the smoke coming off it, and indeed...

..the soot. And that's the problem.

Because in the operation of an engine, there really isn't time

for all those droplets of liquid to burn completely.

So what happens is some of it just gets reduced down

to particles of carbon - soot.

And that means that the exhaust system of a diesel engine has a bigger job to do.

In the last ten years, filters to catch the soot have been introduced to diesel exhausts,

but they can't catch everything,

especially those tiny, invisible particles.

To see how much gets through, I've invited along air monitoring expert, Steve Hoskin.

I've revved the vehicles,

and Steve has been measuring what's coming out of the exhaust pipes.

What's the news?

OK, so, this vehicle, diesel vehicle,

is fitted with a particulate trap, but despite that, it still emits

significantly more particles than the petrol engine.

Our problem in the UK is that we have so many older diesels

that are 10, 12, even 20 years old,

because diesel engines go on for a long, long time.

And the emissions you get are significantly more.

That is a problem that's here to stay, because after many years,

promoted as the more efficient and therefore green option,

we've seen a sixfold increase in the number of diesels on our roads.

And although the filters fitted today are better than ever,

some people even take them out to improve performance.

So what can we do about it?

In the UK, scientists are trying out all sorts of schemes

to clean up the air.

I've come to Sheffield, known as an industrial powerhouse

but now at the forefront of Britain's clean air strategy.

With schemes to encourage you to give up your car for the day

or to take up cycling, and with the introduction of a whole

fleet of hybrid buses and electric cars...

Let's just get this plugged in. There we are.

..This is one city that's really determined to clean up its act.

But while they can help to keep urban air clean, electric cars

mainly just move the pollution to power stations outside the cities.

Materials chemist Prof Tony Ryan has been trying

a novel way to actually mop up pollution from the air.

We want to turn people into environmental cleanup agents

by making their clothes active, so as they wander around

in the sunlight,

their clothes can repair the damage to the air.

These jeans are coated with nano particles of titanium dioxide.

What happens is sunlight comes in so that the photon comes

whizzing in, it messes with electrons on the surface,

they split oxygen into two free radicals,

and they are very, very reactive, they'll react with anything.

Then there's a chain of reactions that then

neutralises the nitric oxide from cars and volatile organics, smells.

So are you suggesting that everyone needs to buy special jeans?

No, not at all.

It could be in the washing powder, or it could be a spray-on thing when you're ironing,

it could be delivered in dry cleaning.

You know, all of your clothes could get treated.

You wouldn't know it was there, you can see it, but if enough of us

did it, there would be a very beneficial effect.

I know that many people would be thinking - what kind of an impact can a pair of jeans make?

One pair of jeans makes virtually no impact.

If the half a million people in Sheffield were wearing

jeans like this, you'd be able to take out about a ton-and-a-half

a day of the nitric oxide, and that would

get us close to the EU limit of 40 micrograms per cubic metre.

Jeans that clean are really just a concept at the moment,

but the same technology is already being tested on Sheffield's streets.

The traffic here is absolutely horrendous.

You've got a really busy slip road that leads up to the M1,

nearly 150,000 vehicles a day passing by.

But this huge wall which is coated in titanium dioxide

forms part of another trial.

Behind it there is a school,

and although it's too early to know whether or not this is making any

real difference, the theory is that it should be reducing

the level of air pollution to which the children are being exposed.

This is just one of the ingenious tactics scientists are trying out.

But it's hard to know how much difference

they might really make, and in London a recent experiment with

sticky roads was deemed a failure.

All the research suggests that the only real solution is

to slash car emissions.

So far, Britain has been slow to face up to this,

and right now the Supreme Court is considering a case

calling for EU targets to be enforced here.

But there are places where they are taking the problem of car emissions much more seriously.

This is Berlin,

a city that tops the league tables for improving air quality.

I haven't been here for ten years,

but walking around this city I've really noticed a difference.

There are fewer cars, the ones that are here are so much cleaner.

More people are walking, more people are using bikes,

public transport is so much better.

The whole place feels cleaner, and that's because it is.

The Berlin government has enforced a total revolution in city transport.

Here emission zones are far stricter than London's,

banning older diesels completely.

Parking is restricted, and bikes are everywhere.

But it hasn't been easy, and it's taken a man with single-minded

vision to make it happen.

Berlin has made some massive changes over the past few years.

One of the most important ones is environmental zones which

keeps highly polluting cars and trucks and buses out of the city.

25% of the cars and trucks produce 75% of the pollution,

so if you keep them out,

you reduce dramatically in a very short time the air pollution level.

You make it sound very easy, but I can't help but think that

some of those measures must have been very unpopular.

The question is, to whom belongs the city? To cars or to people?

In my opinion it's a clear answer - it should be the people.

I think you probably alerted people to the statistics, because

I think many people don't understand the effect of air pollution.

Of course it's important to tell people

60,000 people in Germany every year is killed by air pollution,

which is a dramatic number. We can save people's lives.

We have saved in the last four years 500 people's life per year.

This is an impressive number.

To Axel, pollution is something that just can't be ignored.

It's not a nuisance, it's killing people. It's a silent killing.

As a result of the cleanup, air pollution in Berlin

has fallen dramatically, and most importantly,

diesel soot has dropped by over 60% in four years.

Berlin offers a vision for how our most polluted cities could look

in the future if we make the right kind of changes.

In Britain we've begun to wake up to the problem,

but many of the measures we introduce are piecemeal,

whereas here they have gone for a far more comprehensive approach.

There's no doubt that many of the policies were

deeply unpopular in Berlin when they were first introduced,

but now you've got a city where everyone is benefiting.

I really had no idea how big this problem was,

and you know, if we want to be serious about tackling air pollution

and improve our health as a result, we've got to make some drastic

decisions, and that means fewer cars and cleaner cars.

And it's all too easy for things that we can't see to just

slip off our agenda, but it's time we all cleared the air.

And that's it, not only for tonight, but the whole series.

-So from all of us, good night.

-Bye.

Visit the website at bbc.co.uk/bang

for an exclusive film about pollution and sunsets.

And for more information on air monitoring,

follow the links to the Open University.

Subtitles by Red Bee Media Ltd