Look around you and out of the windows, you can’t see what’s in the air, but it contains dangers to the whole world and to us personally. Carbon dioxide (CO₂)in the air traps the sun’s heat. Too much of it is warming the global climate to harmful levels, if not contained within safe limits this warming will harm our health, our agriculture and the natural world. Other pollutants like nitrogen oxides and ozone have a more localised effect, shortening the lives of more than 7 million people around the world each year. The good news is we can all do things to improve the quality of our air.

In order to combat this damage to our health and our planet, we need to understand how our air quality is impacting our health, how our planet will respond to these increases in greenhouse gases, and create innovative solutions to help reducing the amount of greenhouse gases and pollutants being produced.

This exhibition explores these questions through the lens of research being conducted at the University of Birmingham to help improve the quality of the air we breathe in the West Midlands, and across the world.

The History Of Air Pollution in the West Midlands

The West Midlands was at the heart of the industrial revolution in the 18^th and 19^th centuries. Birmingham was known as the first manufacturing town in the world and the Black Country was a mining and iron working centre.

This period saw population growth, more people living in cities and more industry – the result was an historic increase in air pollution. Thick black soot and smoke poured from the chimneys of the houses and factories and people could see this pollution with their own eyes. Though some saw it as dangerous, many thought it was just the price of living in the modern society and not a major problem.

Global CO₂ concentrations have increased by 50% since the industrial era and today our air pollution is less visible, but we understand the science better.

What Are The Common Pollutants Today?

You may have heard of CO₂ as a pollutant, but there are other pollutants produced as a by-product of transport, industry and energy generation using fossil fuels that find a way into our air.

This might help you to think about what’s in the air all around which are normally invisible. Here are three different particles in the air which are harmful to our health, but invisible to us.

Nitrogen Oxides

The orange particles, which look like three spheres joined together in a chain, represent nitrogen oxides. Power stations release nitrogen oxides when they generate electricity. Nine out of ten homes in England still use fossil fuels for heating, cooking and hot water. But the situation is improving. Over the last thirty years the UK has reduced the proportion of electricity that comes from coal from 70% to less than 3%. Wind is now the UK’s biggest renewable electricity source. On one April day in 2021 windy weather and low demand meant that 80% of our electricity came from low-carbon sources.

We also produce nitrogen oxides when we drive vehicles. The biggest and oldest diesel vehicles are worst. Modern petrol vehicles are cleaner. Electric vehicles can help, as they release no nitrogen oxides or CO₂ but they do still pollute the air with tiny particles from their tyres. Redesigning our cities so we need to drive less is an even better solution.

Ozone

The blue particles, which look like to separate spheres next to each other, represent ozone. Ozone high up in the atmosphere protects our world from the Sun’s UV rays. But it’s harmful if we breathe it in down here. Ozone forms at ground level when nitrogen oxides combine in sunlight with other chemicals in the air.

Particulate Matter

The green particles, which look like a single small sphere with spikes represent particulate matter. These can be up to eighty times smaller than the thickness of a human hair. They get into our lungs and even our bloodstream. Particulate matter can come from vehicle tyres, woodsmoke and farming, such as the use of fertilisers.

To understand how much particulate matter is produced from different activities, Below is a picture of four boxes that show the amount of particulate matter released in to the air from tyres of different vehicles over different time periods.

Visualising Particulate Matter

From left to right:

• The smallest box on the far right contains the amount of rubber released into the air from the tyres of a standard car in one month. It measures 4.4cm³ in size.
• The next box shows what an electric car releases in one year, it measures 16.8cm³ in size. Even though electric vehicles don’t release exhaust fumes, they generally produce more particles from tyre and road wear than petrol and diesel cars, because they’re heavier.
• The third box shows the tyre emissions from the number 11 bus in Birmingham in a two month period. It measures28.7cm³ in size.
• The final and biggest box contains the rubber released from the tyres of the number 11 bus over two years, it measures 65.8cm³ in size.

The heavier bus produces more tyre emissions than a car – but – if you divide this amount by all the people travelling on the bus it works out as much less waste per person than from private vehicles. So, if we all use public transport more, we could reduce the total amount of tyre emissions into the air.

The Impact of Pollutants On Our Planet

It wasn’t until the 1950’s that it became evident that air pollution not only impacts our health but also our planet. Industry, transport and heating release greenhouses gases, which trap more of the sun’s heat in the atmosphere adding to what is called the ‘greenhouse effect’. The most important greenhouse gas is carbon dioxide (CO₂).The greenhouse effect is essential for life on earth because trapping some of the suns heat is what keeps the planet at a stable, habitable temperature. For example, Mars has hardly any greenhouse effect, so it can’t retain energy (in the form of heat) from the sun meaning it has extreme temperature differences between day and night.

However, human activities that produce these greenhouse gases are now increasing the greenhouse effect on our planet so that more heat is trapped, leading to higher temperatures, more extreme weather, rising sea levels and warming oceans.

The Impact of Pollutants On Us

Each year, poor air quality leads to seven million deaths around the world and 500 to 1,000 deaths in the West Midlands. The air in Birmingham does not meet national air quality standards. This issue has a direct impact on our local community.

Air pollution is one of biggest environmental risk to our health. It can reduce life expectancy by an average of up to six months and is particularly dangerous for the most vulnerable, the very young and very old. Over the long term, air pollutants can damage lungs, the heart, blood vessels and brain. Poor air quality can contribute to a baby’s low birth weight and reduce a child’s lung development.

Air pollution can impact nearly every part of the body. This picture below shows the different parts of the body that can be affected by air pollution.

Impact On The Body

• Eyes: Particles dry out and irritate the eyes
• Nose: Particles irritate the cells inside the nose
• Airways: Particles exacerbate symptoms of asthma
• Brain: Early research is demonstrating a link between dementia cognitive decline and pollution
• Heart: Pollution can damage the cardiovascular system
• Lungs: In the short term, coughing, wheezing and shortness of breath and in the long-term risk of lung cancer and respiratory conditions.
• Skin: Particles can irritate skin cells and can lead to rashes and skin disease.

What Is Being Done To Improve Air Quality?

Air quality is highly complex and there are many factors involved. The University of Birmingham - WM-Air Project is building up this type of scientific knowledge of air pollution. For example, this includes measuring the impact of moving from diesel to petrol or electric cars. It puts this knowledge into practice by connecting the University with local partners, including local government, private companies, industry bodies and charities. This work will help us to tackle the air pollution challenges we all face. The project has three broad themes 1) Awareness, tracking sources and levels of air pollution 2) Predictive Capability, building tools to predict air quality and its impacts 3) Application, directly applying the latest science with local partners.

How De Monitor Air Quality?

The photo below is of six air filters. Air pollution is normally invisible to us, but when we look at filters that have been left in the open, air pollution becomes visible. These filters start out white but become darker as they trap pollutants from the air. By leaving filters out for different amounts of time and in different places, we can see how air pollution varies.

These six filters have been exposed to air pollution in different places. The filters are in order of darkest to lightest.

Filters Explained

Imagine they are numbered from left to right:

• Number 1: Old Delhi, India for 12 hours during Diwali Festival. (This filter is black)
• Number 2: Old Delhi, India for 12 hours during the winter. (This filter is between black and dark grey)
• Number 3: Old Delhi, India for 12 hours during the summer. (This filter is dark grey)
• Number 4: Birmingham for 1 day during the winter. (This filter is grey)
• Number 5: Birmingham for 1 day during the summer. (This filter is light grey)
• Number 6: this filter has not been exposed to air pollution (This filter is white)

Other Devices That Measure Air Quality

There are also devices that measure other pollutants such as nitrogen oxide and particulate matter. You might have seen them before on lampposts or street signs around Birmingham. There is a picture of them below. The device that measures nitrogen oxide looks a bit like a test tube and has a disc inside the tube that reacts chemically with gases in the air to indicate how much nitrogen dioxide is present. The device above it is called an altasense sensor and it was created by the WM-Air team to measure particulate matter, such as tyre emissions.

It’s through sensors such as these that the WM-Air can visualise the different levels of pollution, to help inform decisions on what we can do to help reduce it. For example, the map below was produced by WM-Air and it shows the changing levels of one pollutant, nitrogen dioxide, across the West Midlands during an average 24 hours. A major source of nitrogen dioxide is from car exhausts which is why levels increase when there is a lot of traffic, but drop during the quieter hours. The pictures show the highest pollution levels at 4pm – 8pm in the evening and 6am – 8am in the morning with the roads on the map turning dark red and yellow to show these higher concentrations.

The Relationship Between Trees and Our Climate

Trees can teach us a lot about climate - the climate we experience today, the climate of our past, and the climate we can expect in the future. We can learn about climate in the past through studying tree rings, which form each year of a tree’s life. We can use these rings like a time machine to look at what the climate was like in the previous years of the tree’s life, with the rings being wider in warmer wetter years and thinner in colder dryer years. Because trees are so connected to climate, it’s really important that we understand how trees will change in the future with rising CO₂ levels.

Forests absorb up to a third of the extra CO₂ we produce. They absorb atmospheric carbon through the holes in their leaves, which are called stomas, and use it for a chemical process called photosynthesis. In this process, CO₂ from the air and water drawn from the plants roots is converted in to sugars and oxygen using the power of sunlight. Plants use these sugars for energy to grow and release the oxygen into our atmosphere.

A common approach for offsetting CO₂ is to plant more trees. More trees, means more photosynthesis and more photosynthesis means more atmospheric CO₂ being stored.

Visualising The Carbon Storage Of Trees

The photo below shows four piles of dry wood, to help us visualise how much carbon trees are able to store. From left to right:

• Pile 1: Contains 12g of dry wood. This contains the same amount of carbon as the air in the average UK bedroom
• Pile 2: Contains 5kg of dry wood. This contain the same amount of carbon as emitted by a 50 mile (80km) journey in a new car.
• Pile 3: Contains 22ky of dry wood. This contains the same amount of carbon as emitted by the average rail journey from Birmingham to Aberdeen.
• Pile 4: Contains 145kg of dry wood. This contains as much CO₂ as released making the energy to supply the average UK household for a month.

But what will happen when the CO₂ levels in the atmosphere increase beyond what we have today? Will plants take up more or less CO₂? How will this impact plant growth and Will plants still be effective at carbon offsetting?

Introducing BIFoR FACE - The Forest Of The Future

Birmingham Institute of Forest Research (BIFoR) Free Air Carbon Enrichment (FACE) is an experiment being conducted by the University of Birmingham its global partners which aims to help answer these important questions.

The experiment explores how forests will react as CO₂ levels keep rising. The metal masts support pipes, which pump extra CO₂ into the air around the trees – as much as we expect there to be in 2050. Then we measure how well the forest absorbs it.

There are six rings of metal masts like this one which are 30 metres high. In three rings, the masts pump out fresh air into the treetops, but in the other three they pump out extra CO₂. By comparing measurements from the rings, we can learn how forests will respond to rising CO₂. There are only three experiments like this in the world and together they make the world’s biggest climate change experiment, helping us understand how forests will react in the future to the increased levels of CO₂. Below is an image of a model of the experiment in the south foyer of The Exchange.

The Building of BIFoR FACE

BIFoR FACE was installed using the construction equivalent of keyhole surgery. In total 98 masts had to be placed in the centre of the forest. during an incredibly delicate process, each mast was slotted into place with a special helicopter that holds steady when hovering and creates very little downdraft. This reduced the damage done to the trees by wind from the helicopter, which could have impacted the experiment in the future.

BIFoR is one of the most high-tech forests in the world, with an incredible array of devices scattered around the forest to record and monitor lots of different thing to see how they’re impacted by the change in CO₂ levels. For example, Fisheye camera lenses are used to monitor the area of leaves per square meter on the ground, wind flow and windspeed between the trees are assessed using computer simulations, and lasers are used to record 3D digital models of BIFoR FACE and other forests for comparison purposes.

How Can We Make Travel Greener?

As we’ve seen, one of the major pollutants is transport. Different forms of transport have different impacts on the amount and types of pollutants produced. Diesel and petrol cars are a major source of pollution. Another main method of transport in the UK is by train, with over 20,000 miles of track in the UK. Trains are the greenest form of transport, and offer a great alternative to cars, however we can work to make them even more environmentally friendly. Current diesel trains still produce pollutants, and over 1/3 of the UK rail fleet is made up of diesel trains. Electrification of the lines is one way of removing diesel trains and around 40% of the UK rail network now runs on electricity. But electrification is expensive – it can cost up to £1 million to electrify a single kilometre of track. This isn’t cost effective particularly for rural lines with less traffic. The government aims to phase out diesel trains by 2040, so what’s the alternative?

Introducing HydroFLEX, The Hydrogen Powered Train

One option is hydrogen powered trains, which have the potential to be both a clean and cost-effective alternative to diesel. HydroFLEX is the UK’s first hydrogen powered train, engineered by adding a hydrogen power unit to an existing class 319 train.

HydroFLEX is the result of a partnership between The University of Birmingham’s Centre for Railway Research and Education and Porterbrook – one of the country’s top suppliers of train engines and carriages, to combine cutting edge research with commercial application.

It works by combining hydrogen, which is stored in high pressure fuel tanks on the train, with oxygen from the air to create electricity through a chemical process which produces water as a by-product. This electricity is then stored in batteries onboard the train and used power the existing motor on the train.

How Do We Extract Hydrogen?

Hydrogen is the most common element in the universe. On Earth it is normally bound up with other elements, such as carbon or most commonly oxygen in the form of H₂O (the chemical name for water). To use it as fuel, we have to find ways to extract it. Some processes are better for the environment than others.

Scientists talk about ‘grey’, ‘blue’ and ‘green’ hydrogen. Grey hydrogen is produced using fossil fuels - CO₂ is release during its production, so it produces pollutants and contributes to climate change. Blue hydrogen is also produced from fossil fuels but uses technology that captures CO₂ produced. Green hydrogen uses a completely different process called electrolysis to extract hydrogen from water.

Electrolysis Explained

Electrolysis uses the electrical charge to separate the hydrogen and oxygen atoms that form water. An electrical current is run between two electrical conductors called electrodes, one is a positively charged electrode called an anode, and the other is and a negatively charged electrode called a cathode. Hydrogen atoms are produced around the negatively charged cathode and oxygen atoms are produced around the positively charged anode, due to the electrical charges of these atoms when they’re combined to form water compared to the charges of these conductors.

If the electricity used for this process comes from a sustainable energy source, then CO₂ is not released at any point in this process. The challenge is to make green hydrogen in large amounts using electricity from clean energy sources like wind or solar. Then hydrogen trains will be both a clean and affordable alternative to diesel or electric power.

What Can We Do To Help?

As we’ve seen, the causes and impacts of pollution are complex. Research is being done to help understand how it’s affecting our lives, our future, and how we can help change it., We can all do our bit to help improve the quality of the air we breathe by thinking about how we travel, the things we buy, and what we advocate for. We can all help make the change. Below are different pledges visitors can make to help improve the air we breathe, do any of them resonate with you?

• Support a Tree Planting Project
• Become a Tree Warden
• Consider How To Lessen Or Avoid Use Of Diesel Vehicles
• Support Policies That Reduce The Amount Of Road Traffic

Thanks for Exploring the Air We Breathe

Thank you for exploring the exhibition today. We hope you enjoyed it and please follow this link of you have any feedback or comments.