Air pollution

Choked: Air pollution is often invisible, and comes from many different sources.

Seven million people die from air pollution every year. It has been linked to an increased risk of dementia. What is it, how does it work, and what is being done to reduce it?

  • Is air pollution the same as climate crisis?

    No. When people talk about climate crisis, they are talking about the effects of rising temperatures on the Earth’s climate – its seasons, weather patterns, natural disasters, and so on. Air pollution is about the quality of air that we breathe.

  • What is causing it?

    This is where climate crisis and air pollution are closely related. The things that cause one often contribute to the other.

    For example, burning wood or fossil fuels does not just release greenhouses gases that lead to global warming – it also releases particulates into the air. These are tiny particles that get stuck in your lungs and damage your health.

    Many greenhouse gases are also toxic to breathe in large amounts. Take diesel cars: for a long time, they were thought to be cleaner than petrol, but recent studies have found that they release much higher amounts of nitrogen oxides. At high concentrations, these can inflame airways and cause breathing problems. They also react with the sunlight to form smog.

  • So, air pollution is pretty bad for us?

    That is putting it mildly. In 2018, a study in the British Medical Journal linked air pollution to dementia. Although it did not establish a direct cause, it found that people over the age of 50 in London were 40% more likely to get dementia if they lived in an area with high levels of nitrogen oxide.

    What’s more, in 2017, a global report on air pollution said that it kills 7.4 million people per year, costs trillions of dollars, and “threatens the continuing survival of human societies”.

    Deaths from all forms of pollution come to around nine million per year, easily outstripping those from tobacco smoking, AIDs, and malaria.

  • Yikes. Who is most at risk?

    Poor countries suffer the highest levels of air pollution – and the most deaths. This is not just a human tragedy, it also slows down the growth of those countries. And severe air pollution makes everyday life more difficult. Last year, in Delhi, the smog was so thick that five million children were told to stay home from school, flights were cancelled, and factories temporarily closed.

    But air pollution affects everyone, rich and poor. In London, one of the developed world’s wealthiest cities, around 40,000 deaths are linked to air pollution each year.

  • How does air pollution kill people?

    This is where it gets a bit complicated. No death certificate lists “air pollution” as the cause. Instead, it contributes to an overall decline in a population’s health. That figure does not mean that 40,000 Londoners are killed by dirty air, and everyone else is fine. The whole city is affected by it.

    The health problems of vulnerable people are made particularly worse, but other factors can also contribute to their deaths.

    So, while the damage caused by particulates in London is equivalent to 29,000 deaths, it is more accurate to say it led to “340,000 years of life lost”.

  • What is being done?

    Luckily, many of the policies being introduced to tackle climate crisis, such as converting to renewable energies, will also help to clean the air.

    Meanwhile, many countries are rolling out specific air pollution policies. In 2017, the government announced that it would be raising existing taxes on diesel cars and investing £220 million in a clean air fund. London, Bristol and Oxford are both hoping to ban polluting cars from certain areas in the next 10 years.

  • Is it enough?

    Only time will tell – although the head of policy at the Chartered Institute of Environmental Health called the clean air fund’s £220 million a “drop in the ocean”.

You Decide

  1. Is enough being done to combat air pollution?


  1. Look at the graphic at the top of this article, and write out the formulae for the chemical compounds that you see. List the full names of any compounds you know. Research any of which you are unsure, and explain how they contribute to air pollution.

Word Watch

Climate crisis
Some publications, including The Day, are now calling climate change a “climate crisis” to reflect the seriousness of the issue.
Greenhouses gases
Gases like methane, carbon dioxide, and nitrous oxide, which help to trap heat in the Earth’s atmosphere, contributing to global warming. Human activity in the last century has increased the amounts of greenhouse gases in the atmosphere.
A term for a wide range of conditions that affect the brain, causing problems with memory, thinking, behaviour, and emotion.
The Lancet Commission on Pollution and Health (published October 2017) looked at the “full health and economic costs of air, water, and soil pollution”.
7.4 million
Around 4.5 million deaths were linked to outdoor pollution caused by vehicles and industry; 2.9 million were linked to indoor pollution caused by wood and dung stoves.
40,000 deaths
According to a report by the Royal College of Physicians (published February 2016), there were 29,000 “deaths” from particulates and 23,500 from nitrogen dioxide. (They do not add up to 40,000 because there is some overlap between the two.)
Vehicle Excise Duty (VED) is calculated by a car’s age and the amount of emissions it releases.
Certain areas
Oxford city centre will ban petrol and diesel vehicles by 2020, and Central London by 2025. Bristol is set to become the first UK city to ban diesel cars. Under the plans, all privately owned diesel vehicles will be barred from entering a clean-air zone in the city centre, every day between 7am and 3pm, by March 2021.

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