Tom Grylls

And air pollution as a whole is the number one environmental health risk globally.

It contributes to 8 million premature deaths per year, billions of dollars of economic costs through reduced productivity, healthcare costs, shorter lives.

And that number really doesn't tell the real human story of the impacts these are having, where in practice, it goes way beyond that 8 million premature deaths to affecting people's day-to-day lives in so many different ways, particularly those who are at risk, such as older people and people with asthma.

it's not just that stat, but also the respiratory issues, the hospital visits that create this burden that we're in almost everywhere in the world, we're exposed to

air that exceeds the World Health Organization's guideline limits on air pollution.

So pretty much wherever you are in the world, it's likely that one of these pollutants is above the safe level as deemed by the World Health Organization.

So this is a pervasive health problem.

And as we've been touching upon is something that we should and could be talking about more in the context of climate change and tackling these two problems together.

Black carbon, for me, is probably the pollutant that sits most at the heart of that Venn diagram.

So it's a component of fine particulate matter pollution, which is the main form of pollution that is harming our health and that governments are tackling worldwide.

And then it's also basically soot.

So it's the kind of dark sooty material.

Unlike most pollutants, you can literally see it.

There's been campaigns done where people have put sheets alongside busy roads.

And over the course of a day, you see the change of the color of the white sheet to a darker color.

And that stuff is black carbon.

And what that means is it's also on the climate side.

of the Venn diagram, because in being a darker color, it has these light-absorbing properties.

So black carbon in the atmosphere, like if you're wearing a black T-shirt or a white T-shirt, it's changing your retention of heat.

So in the same way, these black carbon particles are absorbing heat and warming the surrounding air, so contributing both to global warming and also locally to extreme heat.