Alarm over air pol­lu­tion

Over 90% of the world’s pop­u­la­tion live in lo­ca­tions with dan­ger­ous lev­els of toxic air­borne par­ti­cles

The Guardian Weekly - - Contents - By Damian Car­ring­ton EN­VI­RON­MENT ED­I­TOR

Why is air pol­lu­tion such a fast-grow­ing con­cern?

Noth­ing is more vi­tal to life than breath­ing: in a life­time, about 250m litres of air passes through your lungs. Yet walk along a busy city street and you will in­hale some­thing like 20m 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 7 mil­lion 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: $225bn in lost labour in­come in 2013, or $5.11tn per year, if wel­fare losses are added in, ac­cord­ing to a 2016 World Bank re­port.

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, with 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 whole of Africa. But air pol­lu­tion af­fects rich na­tions too.

“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 are uniquely vul­ner­a­ble and 300 mil­lion live in places where toxic fumes are six times higher than in­ter­na­tional guide­lines.

Are there dif­fer­ent types of air pol­lu­tion?

Yes. The most dam­ag­ing but best un­der­stood are tiny par­ti­cles, 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, kid­ney and testes in lab an­i­mals. The par­ti­cles are made of black car­bon, ni­trates, sul­phates, am­mo­nia or min­eral dust. Most are pro­duced by burn­ing fos­sil fu­els or wood.

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 ma­nure and fer­tilis­ers blow­ing into cities and form­ing par­ti­cles.

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. Ground-level ozone, which forms on sunny days, harms not only peo­ple but also 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 4.2m early deaths, says the WHO.

What about in­doors?

This is also a huge killer, caus­ing 3.8m early deaths. Half the world’s

pop­u­la­tion cook on open fires with dirty fu­els such as wood, dung and char­coal. Kerosene in wick lamps also pro­duces dan­ger­ous smoke.

More peo­ple are get­ting ac­cess to bet­ter stoves and cleaner fu­els. Among farm­ers in Xuan­wei, China, lung can­cer cases fell by 40% when they switched to stoves with chim­neys.

What harm does air pol­lu­tion do?

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

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.

As chil­dren grow, asthma and stunted lung growth have a se­ri­ous im­pact, but also af­fect the abil­ity to learn in school.

The es­ti­mated an­nual death toll of 7m 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 9m 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 pro­tect­pro­tect­my­self? my­self?

Masks are now com­monly ad­ver­tised, but ex­perts say they are of lim­ited use un­less they have an air­tight seal on the face, which is rare.

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 in the UK. Pol­lu­tion-mon­i­tor­ing apps and walk­ing routes keep pedes­tri­ans away from the filth­i­est roads. Trees can help, un­less they block the breezes that blow pol­lu­tion away.

Peo­ple in cars are of­ten ex­posed to more pol­lu­tion than those out­side. Clos­ing the air cir­cu­la­tion in your car be­fore hit­ting the city is a good idea.

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 King’s 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.”

What next?

“There are two big tran­si­tions we need to have,” says Neira. “One is a healthy en­ergy tran­si­tion and the other is the healthy ur­ban plan­ning tran­si­tion. We need to stop the use of coal, to stop the mas­sive use of pri­vate cars in cities and make our build­ings more ef­fi­cient.”

Coal burn­ing is de­clin­ing glob­ally and China has shown how in­dus­trial pol­lu­tion can be curbed. Par­ti­cle pol­lu­tion is down by a third, just four years af­ter a “war on pol­lu­tion” was de­clared, and eight af­ter Bei­jing’s air was la­belled “crazy bad” when pol­lu­tion leapt off the charts. But cities around the world are ex­pand­ing rapidly, with 4.2bn ur­ban dwellers set to swell to 6.7bn by 2050.

How those grow­ing cities are con­structed is vi­tal, say ex­perts. Mo­bil­ity should fo­cus on walk­ing, cy­cling and pub­lic trans­port - even elec­tric ve­hi­cles throw up par­ti­cle pol­lu­tion from road abra­sion and brake dust. The re­main­ing cars and lor­ries need to be set – and stick to – much stricter pol­lu­tion con­trols.

Build­ings ought to be heated and cooled us­ing re­new­able en­ergy and waste should not be burned with­out strin­gent con­trols.

Progress is be­ing made. Some Dutch and Dan­ish towns have turned their back on cars and Seoul in South Korea has de­mol­ished 15 ex­press­ways in favour of bus lanes and a new river. But some mo­tor­ing lob­bies and car man­u­fac­tur­ers re­main ob­sta­cles.

Neira, a for­mer health min­is­ter in Spain, says politi­cians should play the health card: “If you re­duce cases of asthma, ev­ery­body will love it.” Other rea­sons for ac­tion are the cli­mate change ben­e­fits of cut­ting coal, oil and gas burn­ing and the re­duc­tion in obe­sity that fol­lows more ac­tive travel, such as cy­cling.

What must be done to end the air pol­lu­tion emer­gency is not the is­sue, says Neira, it is the lack of se­ri­ous po­lit­i­cal will: “There are plenty of ideas and so­lu­tions. It takes lead­er­ship.”

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