Things I didn’t know about air pollution

Before coming to the UK, I never paid that much attention to air pollution. I can’t even claim complete ignorance – I learnt about air quality in the same subject as climate change at university. But you can probably tell from the content of the blog which issue captured my imagination more!

However, since coming to the UK I have learnt quite a bit about air pollution and the detrimental impacts it has on human health (probably more than anything this is because I spend many days sitting next to an air quality specialist!).

It isn’t just me that is waking up to this issue. The theme of this year’s World Environment Day (5 June) was Beat Air Pollution. And this week in the UK it is Clean Air Day (20 June). To jump on the theme bandwagon, this post is a round up of not so fun facts about air pollution and what we can do to address it.

What are the causes of air pollution?

According to the United Nations Environment Programme (UN Environment), there are five main causes of air pollution globally:

  • Household – Fossil fuels and biomass (wood and other plant-based fuels) are burned by about 3 billion people worldwide for cooking, heating and lighting. This results in poor indoor air quality.
  • Industry – Power generation using fossil fuels not only contributes to the climate crisis, but also causes local air quality issues.
  • Transport – As for industry, burning fossil fuels in transport also contributes to both the climate crisis and air pollution.
  • Agriculture – Methane emissions from agriculture are not only a potent global warming gas, but also contribute to the formation of ground-level ozone.
  • Waste – Landfills and incineration both result in emissions of air pollutants.

Of all these sources, vehicles burning fossil fuels are the biggest air pollution concern for people living in cities in countries like the UK and Australia.

I kind of assumed that air quality would be worse close to a coal-fired power station than in a city. But actually, according to the World Health Organization’s global ambient air pollution map, air quality is worse in Melbourne than in the Latrobe Valley (where there are a bunch of brown coal mines and power stations that burn it).

What are the impacts of air pollution?

Air pollution certainly has impacts on the environment, however more than perhaps any other environmental issue there are direct detrimental impacts to people.

The World Health Organization (WHO) has set air pollutant levels which define the safe limit for people. However these are exceeded in many places. In fact, 92% of the world’s population lives in places where air quality levels exceed WHO’s Ambient Air quality guidelines for annual mean of particulate matter with a diameter of less than 2.5 micrometres (PM2.5), according to a 2016 assessment. If you want to find out how the place where you live stacks up, this interactive map shows global ambient air pollution levels.

(Note that particulate matter is not the only pollutant of concern, there is a whole alphabet of harmful compounds in the air we breathe (NOx, SOx, VOCs, ozone…the list goes on). Public Health England has a very helpful summary of them here.)

For those of us living in areas with excessive air pollution (probably most people reading this!), there are a multitude of health impacts. Air pollution causes 7 million premature deaths each year, 4.2 million as a result of ambient air pollution and the remainder as a result of household air pollution. That’s not to mention the increased instances of physical and mental illness. Here is a terrifying (but very interesting) summary of how air pollution can damage every organ and cell in the body.

And much like the climate crisis, air pollution is a social justice issue. Those that are most affected tend to be those that are most vulnerable, both on a global and local scale.

What can be done about it?

The climate crisis and air pollution have many of the same causes (i.e. burning fossil fuels!), so many of the solutions are also the same. For example, renewable energy will take over from coal-fired power stations, bikes and electric vehicles will take over from petrol and diesel cars.

In some ways, air pollution is an easier challenge to address than climate change. The impacts of poor air quality are felt more locally to the source, and more immediately in terms of the health impacts described above. Every day more data is collected about the air quality in different locations, and maps like the one below make this information widely available, if you are looking out for it. Soon it will be possible to track the emissions from every power plant in the world in real time (the project involves satellite imagery and artificial intelligence, very cool!). As the saying goes, knowledge is power, and data means that it is possible track where there is lots of air pollution.

A global map of air quality. The live version is mesmerising, check it out at

Legislation and regulations provide mechanisms for forcing governments and businesses to address air pollution. I was intrigued to find out that the UK Government has been sued by ClientEarth (an environmental law charity) three times for a failure to address illegal levels of nitrogen dioxide.

One of the ways that this issue is being addressed in the UK is through the introduction of Clean Air Zones (CAZ, yet another thing I had never heard of before arriving in the UK). According to ClientEarth, “these are areas where vehicles are restricted from entering if they do not meet minimum standards for emissions of air pollutants. Non-compliant vehicles can either be charged to enter the CAZ or banned from entering with fines applied if they do enter the CAZ”. The most famous of these is probably the London Ultra-Low Emission Zone, which came into force earlier this year and seems to be working. According to the Mayor’s Office, the number of highly-polluting vehicles entering the city has dropped since it was introduced, but I was also interested to see that the overall number of vehicles in London has dropped as well in recent years.

As someone that doesn’t drive, this all sounds like a wonderful idea!

What practical actions can individuals take?

As for governments and businesses, fortunately actions that individuals are already taking to minimise greenhouse gas emissions will also improve air quality!

If you want to pick one thing to change, my top tip is to get on your bike.

Riding a bike has health benefits over driving even when exposure to air pollution is taken into account. In fact your exposure to air pollution is likely to be less when riding a bike than when stuck in a car in traffic. Environmental charity Hubbub recently ran an experiment in London, where they tracked air pollution exposure by 10 commuters using different transport modes. They found that those inside vehicles (particularly the truck drivers) were exposed to worse air quality than those that were outdoors (cycling and walking). It seems a bit counterintuitive, but this finding is backed up by numerous scientific studies.

Biking isn’t possible for everyone all the time, but I can personally vouch for the well-being benefits of a relaxing bike ride over being stuck in traffic. Plus it reduces your contribution to local air pollution and the climate crisis at the same time. Win win for everyone!

Also, for any Australian readers, there is currently a consultation open on proposed updates to the ambient air quality standards. If you want to help make sure that these align to what the WHO considers is safe, you can go along to an event or respond here.

Related reads and listens:

If you are looking for more inspiration, UN Environment has a list of suggested actions for World Environment Day. Hubbub have also put together an action list as part of their #AirWeShare campaign.

The most recent episode of Outrage and Optimism focuses on the devastating impacts of air pollution.

I recently raced through Choked by Beth Gardiner. It is a terrifying and epic read, highly recommended! If you can’t get your hands on it immediately, check out her published articles.

Choked by Beth Gardiner, a gripping read (perfect for a week of long train journeys)
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