Ev­ery­thing you should know about air pol­lu­tion

It isn’t just cars that fill our ur­ban cen­tres with par­ti­cles. Damian Car­ring­ton ex­plains why air pol­lu­tion is on the rise – and what we can do about it

The Guardian - Journal - - Front Page -

Why is air pol­lu­tion such a fast-grow­ing con­cern?

Noth­ing is more vi­tal to life than breath­ing: in an av­er­age life­time, about 250m litres of air passes through your lungs. Yet walk along a busy city street and you will in­hale some­thing like 20m harm­ful par­ti­cles in a sin­gle lung­ful.

Toxic air is now the big­gest en­vi­ron­men­tal risk of early death, re­spon­si­ble for one in nine of all fa­tal­i­ties. It kills 7m peo­ple a year, far more than HIV, tu­ber­cu­lo­sis and malaria com­bined. Dr Maria Neira, the World Health Or­gan­i­sa­tion di­rec­tor with re­spon­si­bil­ity for air pol­lu­tion, is blunt: “It is a global pub­lic health emer­gency.”

How much does it cost us?

The lost lives and ill health caused are also a colos­sal eco­nomic bur­den: £173bn ($225bn) in lost labour in­come in 2013, or $5.11 tn per year (about $1m a minute), if wel­fare losses are added in, ac­cord­ing to a 2016 World Bank re­port, which called the fig­ure “a sober­ing wake-up call”. Air pol­lu­tion is get­ting worse in the de­vel­op­ing world and, while it is get­ting bet­ter in some de­vel­oped na­tions, our knowl­edge of how com­pre­hen­sively it dam­ages our bod­ies and minds is grow­ing even faster.

Dirty air has been with us for cen­turies – pre­vi­ously, we sim­ply lived with it – and no one has yet had air pol­lu­tion as a cause of death on their death cer­tifi­cate. It is only in re­cent decades that the dam­age to health has be­come clear, and in the last few years that the cri­sis has re­ceived wide­spread at­ten­tion, thanks to re­search rev­e­la­tions, gov­ern­ment le­gal de­feats and the Volk­swa­gen diesel scan­dal.

But there is a sil­ver lin­ing to air pol­lu­tion’s cloud of smog: ac­tion to cut it not only brings im­me­di­ate ben­e­fits but also helps fight cli­mate change in the longer term.

Who does it af­fect?

Over 90% of the world’s pop­u­la­tion lives in places where air pol­lu­tion is above WHO guide­lines. It is worst in south and east Asia, where most of hu­man­ity lives, thanks to traf­fic, dirty in­dus­try and the open burn­ing of waste. In­dia has al­most half of the top 50 most pol­luted cities in the world, China has eight and Iran has three. Africa is highly pol­luted but lit­tle mea­sured: in 2015, Paris had three times more mon­i­tor­ing sta­tions than the en­tire con­ti­nent. But air pol­lu­tion af­fects rich na­tions.

“The trends are pos­i­tive if we look at the last 50 years, but it de­pends how many deaths are you ready to ac­cept,” says Neira. “We still have 500,000 deaths in Europe [per year] and this is to­tally un­ac­cept­able.” Chil­dren’s de­vel­op­ing bod­ies are uniquely vul­ner­a­ble, but 300 mil­lion live in places where toxic fumes are six times higher than in­ter­na­tional guide­lines rec­om­mend.

Are there dif­fer­ent types of air pol­lu­tion?

Yes. The most dam­ag­ing but best un­der­stood are tiny par­ti­cles (PM2.5s), which harm the lungs and en­ter the blood­stream. They are in­creas­ingly thought to en­ter vi­tal or­gans, in­clud­ing the brain, and have been shown to reach the liver, spleen, kid­neys and testes in lab an­i­mals. The par­ti­cles can be made of black car­bon, ni­trates, sul­phates, am­mo­nia or min­eral dust. Most are pro­duced by burn­ing fos­sil fu­els or wood, for trans­port, heat­ing, power plants and in­dus­try.

In some coun­tries, im­prove­ments have been made to coal-fired power sta­tions and cars, but other sources of pol­lu­tion lag be­hind. Farm­ing is one source, with am­mo­nia from live­stock ma­nure and fer­tilis­ers blow­ing into cities and form­ing par­ti­cles, par­tic­u­larly in the spring. Ni­tro­gen diox­ide, pro­duced by diesel ve­hi­cles, not only forms par­ti­cles but is now known to cause harm when breathed as a gas. It is still il­le­gally high in much of ur­ban Bri­tain, where it re­sults in about 23,500 early deaths.

Other pol­lu­tants in­clude sul­phur diox­ide, which is still very high in ship and avi­a­tion fu­els. Groundlevel ozone, which forms on sunny days, harms peo­ple as well as crops: 7-12% of the global wheat crop is es­ti­mated to be lost in this way; in In­dia, crop yields are re­duced by 28%.

There are some nat­u­ral sources, such as dust storms and smoke from for­est fires, but hu­man-caused pol­lu­tion far ex­ceeds these. Out­door air pol­lu­tion causes 4.2 mil­lion early deaths, says the WHO.

What about in­doors?

This is also a huge killer, caus­ing 3.8 mil­lion early deaths. Half the world’s pop­u­la­tion cook on open fires with “dirty” fu­els such as wood, dung and

A burn­ing is­sue

The im­pact of wood-burn­ers on western city air has sur­prised re­searchers. “It has crept un­der the radar,” says Prof Gary Fuller, at King’s Col­lege Lon­don.

As many as 1.5m stoves have been sold in the UK, and 40% of par­ti­cles in Bri­tish cities are from wood burn­ing, more than dou­ble than the emis­sions from ve­hi­cles. The same rise has been seen in France, Ger­many and Bel­gium, while Aus­tralia and parts of the US and Canada have had sim­i­lar is­sues. In New Zealand, wood burn­ers spew out up to 90% of par­ti­cle pol­lu­tion.

In many Euro­pean cities peo­ple burn waste wood, of­ten cov­ered in lead paint, putting toxic metal into the air. But gov­ern­ment ac­tion is bit­ing. Mon­treal has banned all but the most mod­ern and least pol­lut­ing stoves and old, smoky burn­ers are be­ing scrapped in Crested Butte, Colorado. char­coal. Kerosene in wick lamps also pro­duces dan­ger­ous smoke. How­ever, more peo­ple are get­ting ac­cess to bet­ter fu­els and stoves. Among farm­ers in Xuan­wei in China, lung can­cer cases fell by 40% when they switched to us­ing stoves with chim­neys in their homes. But with the global pop­u­la­tion ris­ing, the num­ber of peo­ple ex­posed to in­door pol­lu­tion is not fall­ing.

What harm does air pol­lu­tion do?

It is eas­ier to ask what harm does air pol­lu­tion not do. Re­search links toxic air not only to al­most ev­ery part of the body, but also the mind.

The land­mark re­search link­ing air pol­lu­tion to lung dis­eases, heart at­tacks and strokes – the Har­vard six cities study – was first pub­lished in 1993. Since then dirty air has been linked to many con­di­tions, such as di­a­betes. Air pol­lu­tion con­trib­uted to 3.2m new cases of this ill­ness in 2016, ac­cord­ing to one study. Kid­ney dis­ease ap­pears to be in­flu­enced by air pol­lu­tion, as does Alzheimer’s. Skin ages more rapidly in dirty air.

The re­search on ba­bies and chil­dren is par­tic­u­larly wor­ry­ing. A large re­cent study found toxic air sig­nif­i­cantly in­creases the risk of low birth weight, lead­ing to life­long dam­age to health.

Mil­lions of pre­ma­ture births may be linked to air pol­lu­tion; an­other study makes the con­nec­tion to birth de­fects and an­other to cot deaths. The first di­rect ev­i­dence of pol­lu­tion par­ti­cles in moth­ers’ pla­cen­tas has also been re­vealed.

“It is a wor­ry­ing prob­lem – there is a mas­sive as­so­ci­a­tion be­tween air pol­lu­tion a mother breathes in and the ef­fect it has on the foe­tus,” said the lead re­searcher.

As chil­dren grow, asthma and stunted lung growth has a se­ri­ous im­pact, but pol­lu­tion also af­fects the

Pol­lu­tion and the brain

A ma­jor study pub­lished in Au­gust Au 2018 found that air pol­lu­tion causes a “huge” re­duc­tion in in­tel­li­gence. For the worst af­fected cat­e­gory, older men, the dam­age is equiv­a­lent hav­ing spent fewer few years in ed­u­ca­tion, pos­si­bly due to in­flam­ma­tion of the brain. The av­er­age dam­age across men a and women of all ages was one lost year of learn­ing. Re­cent re­search also links air pol­lu­tion to men­tal ill­ness, par­tic­u­larly the risk of sui­cide. A study in Hong Kong found spikes in toxic air cor­re­lated with “ex­tremely high mor­tal­ity” in peo­ple with men­tal dis­or­ders. The same link was was found in Bel­gium, even when pol­lu­tion was be­low belo le­gal lim­its. . Sim­i­lar re­sults have ha been found in Salt Lake City, Utah, South Korea and, in peo­ple un­der 30, in Tokyo. Re­search in Lon­don found peop­ple peo­ple over 50 in ar­eas with the high­est ni­tro­gen diox­ide pol­lu­tion had a 40% greater risk of de­vel­op­ing de­men­tia. abil­ity to learn in school and even the risk of teenage delin­quency.

The es­ti­mated an­nual death toll of 7 mil­lion is an un­der­es­ti­ma­tion, as it only in­cludes par­ti­cle pol­lu­tion and the five most firmly linked causes of death, such as heart at­tacks. Early es­ti­mates us­ing im­proved mod­els sug­gest a to­tal fig­ure of 9 mil­lion from par­ti­cle pol­lu­tion. Even this is only “the tip of the ice­berg”, ac­cord­ing to re­searchers. Ex­po­sure to air pol­lu­tion is likely to dam­age the health of al­most ev­ery­one.

The WHO is clear: “The bur­den of dis­ease from [out­door] air pol­lu­tion is ex­pected to greatly in­crease.”

Can I pro­tect my­self?

Masks are com­monly ad­ver­tised, but ex­perts say they are of lim­ited use un­less they are air­tight.

Gi­ant tow­ers, street-side benches and liv­ing, green walls have all been pro­posed to fil­ter dirty air. A new bus aims to fil­ter air as it trav­els around Southamp­ton. Pol­lu­tion-mon­i­tor­ing apps and walk­ing routes that keep pedes­tri­ans away from the filth­i­est roads are use­ful. Trees can help, un­less they block the breezes that blow pol­lu­tion away.

Peo­ple in cars are of­ten ex­posed to more pol­lu­tion than those out­side, as fumes be­come trapped in the cabin. Clos­ing the air cir­cu­la­tion in your car be­fore hit­ting the city cen­tre is a good idea.

There is also some ev­i­dence that omega oils and vi­ta­min B may of­fer some pro­tec­tion against the dam­age caused by air pol­lu­tion.

Isn’t that treat­ing the symp­tom, not the cause?

Yes. The only prac­ti­cal way to tackle the global health emer­gency is to cut lev­els of pol­lu­tion at source. There is an eth­i­cal an­gle too, says Prof Gary Fuller, at Kings Col­lege Lon­don: “Morally it is not right to make the vic­tims change their be­hav­iour, in­stead of the cul­prits.”

Poorer peo­ple are also most ex­posed to air pol­lu­tion. “There are huge in­jus­tices at the heart of the air pol­lu­tion prob­lem,”’ says Fuller. “By us­ing our air to dis­pose of their waste, pol­luters are de­stroy­ing a shared re­source and avoid­ing the full cost of their ac­tions.”

In­dia has al­most half of the top 50 most pol­luted cities in the world, China has eight and Iran has three

Source: Na­tional At­mo­spher­ics Emis­sions In­ven­tory

UK PM2.5 pol­luters in kilo­tonnes, 2016

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