What You Are Made Of: Not Just Particles Of Matter, But Particulate Matter…

It’s mid-September a few years ago, 10 am. I’m cycling on a smooth road, a tough 8% grade climb in the Ardennes Forest right on the Luxembourg-Belgium border. It’s super quiet, cool in the early autumn air and the sun peppering through the pine forest canopy. I can hear my deep breaths echo, with the distant faint sound of birds in the forest. It smells sweet, fresh with a hint of woody damp. I tilt down my tinted cycling glasses to look at this beauty with my own eyes - and it is a beauty - a forest in all its splendour - carpeted with bright green moss. It just feels so good to have this moment to myself and enjoy a small pleasure in our world. Then I hear it. The low drone of an oncoming car. It gets louder and louder. I’m all over the road, zig-zagging, trying to get up this tough climb so I pull close to right to let them drive past. It was an SUV. I didn’t know the model exactly as it was moving fast, but it had four shiny exhausts. The driver very politely waited till the road was straighter, then accelerated around me. I couldn’t see any smoke or steam or exhaust of any kind when he drove past, but I did instantly get the smell. When you are pushing hard up an 8-10% climb for 10 minutes or so, your lungs have opened. Your heart rate is in the 90+ percentile and you can’t just simply hold your breath! It’s toxic. The smell and taste. It’s difficult to describe the smell of diesel fumes exactly, I think it’s somewhere between burning plastic, motor oil and cigarettes. The taste is metallic, iron mixed with burned toast.

I’m not an environmentalist and never campaigned about, or to be totally truthful, thought much about the environment, my air or the planet. I often used to repeat a joke I heard somewhere from a comedian – “What’s the environment ever done for me?” But that was then, that was my ignorance about what was going on around me, what my contribution to the planet is and how it affects me. So, the smell and taste of a diesel car in the beautiful forest while out for a spin on my bike bothered me. It ruined that lovely moment – boo-hoo. A bit of a first-world problem, isn’t it? But the smell lingered a bit in the windless woods. I could smell and taste that diesel extract long after the car had vanished down the road. With no wind, it just lingered and slowly dissipated. Finally, it was gone. No more smell or trace - great I can breathe again, but where did it go? This question and a desire to go deeper into the origin and content of that smell drove me to investigate further and further in the months that followed. The smell didn’t magically leave the planet, just because I couldn’t notice it after a while. It stays with us. Forever. It just thins out to a point where our olfactory sensors can’t detect it anymore.

It’s partly an aerosol. This means the particle diameter of the exhaust emissions are comprised of a small enough mass that they can become suspended in the air for hours. Just like Covid-19. Like the perfectly still dust motes you see suspended in mid-air when in a dark room with a slight gap in the curtains sending a sunbeam through. Some of the particles fall to the floor as they are bigger. This is known as Particulate Matter or PM. These PM particles have a certain mass and size which interacts with our planet, environment, and us in different ways. The infamous PM 2.5 or smaller is the diameter of diesel emissions that can cause cancers, respiratory infections, and death, especially for the vulnerable, like Covid-19 victims.

You put food and drinks in your mouth every day. You know what you like, what tastes good or doesn’t. You also have an instinctive survival trait to avoid contaminated foods. Foul-smelling food or unattractive dark colouring will normally subconsciously make you avoid it. It’s a basic survival instinct. You have a conscious choice - put it in your mouth or not. You don’t have the same choice when it comes to the air you breathe - so suck it up…but at least know what you are putting into your body, via your lungs, every day.

Our atmosphere is comprised of oxygen, 21%, nitrogen 78%. The remainder is gasses like carbon dioxide and methane. These gasses, representing less than a tenth of a percent, may seem insignificant, yet they have a disproportionate effect on our existence. This mix, which has changed little over recent millennia enables life in abundance. The change of oxygen content in the atmosphere over aeons, combined with the seasons, has created the incredible diversity of animals and plants that comprise our ecosystem. Continuous change in adapting to Earth’s atmospheric and temperature conditions created survival competition. Over millions of years, these changes allowed only the most adaptable animals to survive and thrive. 99.9% of all life that ever lived on Earth didn’t make it - they are extinct. The predators of the world had to become smarter and smarter to survive and stay fed. This slowly made intelligence one of the most important tools of any species. Eventually, there were apes using tools, making clothes to keep warm and building shelters. Amongst all the mighty predators the planet had seen over the millennia, one of the least likely animals rose and came to dominate the planet - us.

However, now, due to our intelligence and ingenuity, air pollution causes seven million premature deaths per year, more than double Covid-19’s toll as of mid-2021. The World Health Organisation (WHO) estimates direct exposure to diesel in its liquid form can cause serious kidney damage. According to the WHO, Diesel is a group 1 carcinogen. Nitrogen Oxides (NOx) and PMs from diesel fumes, are responsible for 36,000 premature deaths a year in the UK alone, surpassing deaths from tobacco or obesity.

According to the American Cancer Society experiments with diesel fume exposure in animals has been found to causes alteration to the DNA of cells and has a direct link to lung cancer. There have also been multiple links found between exposure to diesel fumes and increased cancers of the throat, larynx, and stomach. There are ongoing investigations to links between exhaust fumes and increased chances of leukaemia in children. There is no question that diesel and petrol fume exposure is a detriment to human and animal life. Dr. Jonathan Grigg, from Doctors Against Diesel states “If you’re going to design something that would effectively deliver a toxic substance into the lungs, you couldn’t do better than the diesel soot particle.”