13:04

We’ve reached the Pacific Ocean, where air pollution blissfully drops away to near zero.

Thanks for joining us for a snapshot of air pollution on this otherwise unremarkable Monday in February 2017. The results have been worrying.

Air pollution is one of the leading preventable causes of death in the world, killing nearly 7 million people a year – mostly in urban areas. Indoor air pollution is responsible for roughly half those deaths. And exercising outdoors in several cities is actually worse for your health than doing nothing at all.

We started the day in Beijing’s evening, where we learned that some Chinese have started referring to smog as “the weather” and saw this disturbing video:

Chas Pope (@china_chas) Bank of AQI400+ smog rolling into Beijing just now - within 20 minutes https://t.co/jbk3byT37C #beijing #airpocalypse #smog pic.twitter.com/Sf5Zom6F9M

In Delhi, Michael Safi showed us his cigarette-packet-warning-esque air filter ...

michael safi (@safimichael) Air filter, new and after five months in Delhi 😷 #GuardianCities pic.twitter.com/Jxn6OMUWCA

... and we strapped an air pollution monitor to a rickshaw:

We visited Almaty, Kazakhstan ...

Holy shit #thatview #smog #almaty #kazakhstan #koktobe #incredible #sun #air #bluesky #cityscape A photo posted by KIRILL BUKKA - DJ - PRODUCER (@kirillbukka) on Feb 7, 2017 at 10:53pm PST

... Lagos ...

Oghenefejiro (@HadassahEgbedi) The rapid pace of industrialisation in this city is both a blessing and a curse; residents choke on their commute daily. #GuardianCities pic.twitter.com/OtA0qEhmgr

... and Stockholm:

What time is it? Smooth breathing time ... handout for the air mask company Airinium

And finished up by passing through Manchester, London, Rio ...

... the South Bronx’s infamous “Asthma Alley”, Mexico City and our last stop: the Los Angeles house that is literally next door to an oil refinery.

Nate Berg (@nate_berg) Outdoor air quality, Wilmington: 10 micrograms of PM2.5 per cubic meter; 507 ppm of CO2; 44% humidity; moderate AQI of 42 pic.twitter.com/XfTIeRsDh7

Stay with us tomorrow as our air pollution series The Air We Breathe continues with an interactive on how air pollution increases your chance of death, an exclusive investigation of a steel scandal in Bosnia and a look at the “Trump effect” in Bakersfield, California, the worst city in the US for air pollution.

And due to popular demand we’ll get to the bottom of whether you’re going to have to get used to the fact that air masks are going to become trendy. Which, given today’s results on our portable air pollution monitors, you almost certainly are.

Thanks for joining us.

