On a good morning, from my Beijing tower block, I could gaze across the city to the hills far to the west. On the worst days, when pollution levels soared off the scale, I could barely make out the buildings across the road. The air purifiers in each room were turned up to 11. The filters inside were supposed to last for six months – but after just a couple of months, the pristine white folds had usually turned charcoal grey.

Even with a mask, 20 minutes outside could leave you feeling nauseous. Friends complained of sore throats and coughs that never went away. It was a running, though unamusing, joke: Airmageddon. The airpocalypse. Beige-jing. But it got inside your head as well as your system. After a spate of especially bad days, my spirits lowered. I longed to see the sky.

And then one spring I returned home for a holiday, and turned the corner at the Peak District’s Surprise View, one of the loveliest I know. Below me lay the Hope Valley, and, to my horror, the smog lay thick in its bottom. It took me a moment to recognise my error. Pollution had become so normal to me that, even at a place I knew so well, and had seen shrouded so often, it had not occurred to me that it was just mist.

In primary school my teacher had described climbing up to the hills as a child, and being unable to see Sheffield thanks to the blanket of smog. So many years after the Clean Air Act, it had been unimaginable to us. Now I took toxic air as the norm, like so many in China. I rolled my eyes when headlines shouted about the UK’s air pollution crisis in April 2014. It was, by Beijing’s standards, a pretty clear day.

Now I live in London again and note each morning how good it feels to breathe clean air. But I’ve noticed, too, how unpleasant it can be to walk along Euston Road. And I’ve started to ask myself why I’ve regarded illegal levels of pollution as acceptable. It is hard to see how our own attitudes – what we notice, what we tolerate – shift and how dependent this is on the views of people around us. To begin with, I took Beijing’s bad days for granted. I lived there for five years before getting purifiers. No one liked the filthy air: but most residents regarded it as inevitable, like bad weather. Masks were seen as at best an eccentricity, at worst an indulgent affectation. The only Chinese people who wore them were warding off infections or trying not to spread them.

It’s hard to pinpoint exactly when things changed. The research was piling up – scary data on the long-term health impacts: early deaths, heart and lung problems, cancer, diabetes, birth defects. So was the anecdotal evidence: toddlers who developed terrible asthma; the previously healthy friend who found himself waking in the night, struggling to breathe. Soon we were checking an air pollution app each morning, and discussing air purifiers and masks as petrolheads might compare sports cars. Private schools acquired inflatable domes so pupils could exercise without going outside.

We could afford to do this. Whether in Birmingham, Beijing or Delhi, pollution disproportionately affects the poor. They are more likely to live in heavily polluted areas (near factories or main roads, say) and are by definition less able to afford even partial remedies. But no one can escape the problem entirely.

Politburo members also looked out on a wall of grey, and presumably their sisters and sons were complaining, and their grandchildren too were racked by coughs. In 2015, hundreds of millions of people watched the documentary Under the Dome, which laid out the impact of pollution on China in frightening detail. It was a turning point in public awareness – and strikingly, while it was eventually censored, it had received at least partial official backing. Some within the leadership had realised that it had to take action, even if there is still a very long way to go.

That British problems are less severe does not mean we can afford to ignore them. The impact of nitrogen dioxide levels on our health, and especially that of our children, whose developing lungs are so much more vulnerable, is undeniable. The high court has twice judged the government’s response to air pollution as being illegally poor.

Measures such as masks and purifiers may help individuals and even save lives. But they are not enough. The true significance of their adoption in China was that they showed people were recognising the problem. Their popularity helped to reinforce the sense that such concerns were sensible and pressing rather than peculiar or trivial. The real solutions are social – taken by city leaders, national governments and international bodies. But they will act only when the rest of us decide we have had enough.