I was sat in one of Beijing's growing number of Starbucks when I was first told of girl X.
The air outside was thick with smoke from the city's coal fired power stations and I had taken shelter. A journalist friend handed me his phone. On it an article from the People's Daily about China's youngest lung cancer victim - a girl who could not be named - from Jiangsu province. She was eight years old.
The pollution outside, an eerie yellow cloud, veiled the city, enveloping skyscrapers obscuring anything beyond the fifth floor. Girl X's doctor had, without equivocation, gone on record at great risk to his freedom to declare that very pollution as accountable for her condition.
As our political leaders meet in Paris this week to reach an agreement on tackling climate change we are asked to imagine a dystopian world where the catastrophic effects of failing to decarbonise our economies takes hold. We don't have to. Girl X is the face of that future if we fail to act, and cities like Beijing offers us a dubiously voyeuristic opportunity to peer into its abyss.
Last week, again, Beijing faced down down severe pollution. For those of us who have lived there, this is nothing new. An annual tragedy which engulfs its 21m inhabitants between the months of December and February when the weather becomes cold, the blinding inescapable smog, or 'fog' as the Government would call it, has even the youngest and fittest hacking up black soot from the back of their mouths. And in my case, blood.
Expats friends still living in Beijing joke that they have taken up smoking to guard themselves against the effects of poor air quality, the cigarette's filter protecting their lungs from the pollution.
The pollution - effluence from China's rapid, rampant industrialisation - peppers the air with tiny particles (PM 2.5) some 28 times smaller than the breadth of a hair which lodge deep into the lungs and can enter the blood stream.
The World Health Organisation recommends the level of these PM 2.5 particles in the air should no higher than 25 micrograms per cubic metre. Beijing's reading last week in one part of the city was 2,242.
To put this into perspective, today in Paris the air quality index (AQI) - a calculation used by Governments including the Chinese to communicate pollution levels to the public - stands at 70. A score below 50 is considered good (about 30 micrograms per cubic metre). In London the AQI currently stands at 83. In Beijing, at the time of writing, it currently reads 274.
I remember the count on the day of first hearing of girl X. It was 876. The AQI scale is only supposed to reach 500.
The business I then ran, which sold anti-pollution masks and indoor air purifiers, had to install three new phone lines as hundreds of worried Chinese and expat families rang through orders, each of thousands of pounds in value, to protect themselves and their children against the impending 'airpocalypse'.
It's no surprise that in order to get the AQI figure I and many others had to use a virtual private network, which routed my internet connection back through the UK, to access a website giving live information on the particulate matter reader atop the US Embassy building in Beijing. The Chinese government continues to block access to the website.
Girl X, for me, represents the tragedy that faces us if we don't act. It also represents the shame of the Chinese government in feigning ignorance of the problem, and indifference to its solution.
Inner-city air pollution is a blight which affects us all. The framework agreed in Paris gives us the opportunity to tackle the catastrophic effects of climate change from pollution in the long-term. But we must take action in the short term too.
London isn't Beijing. There, schools are closed and building sites shut down to guard against the effects of suffocating pollution. Yet air quality in UK and other European cities is creeping towards the future we all don't want to imagine.
Carbon-sink building materials, bike helmets which ionise particulate matter, monitoring PM2.5 levels at building sites and major traffic junctions. All seeming technologies of the future but all offering potential solutions to London's worsening air problem. It's time we have that conversation, before it's too late.