Pollution is a fact of life on Earth, with even “natural” sources like plants, pets and fungi, emitting harmful matter into the air we breathe. So, what are the worst pollutants we encounter and how can we mitigate their effects?
One of the worst culprits for affecting our health is particulate matter (PM). It comes in three sizes: coarse (PM10); fine (PM2.5) and ultrafine (UFPs). PM10 particles range between 2.5 and 10 microns. A micron is a thousandth of a millimetre and we can generally see anything above 25 microns with the naked eye. In terms of PM10 particles, think dust or smoke or airborne liquid droplets. These irritate not only our eyes and skin but our nasal passages, throats and breathing.
PM2.5 pollution is too small to see, but it’s there nonetheless: microscopic bits of pet fluff and shed skin, mites, and airborne construction debris. The problem with PM2.5 is that its tiny size means it can get into your lungs, causing asthma and respiratory infections and diseases. Over time these can reduce life expectancy.
UFPs are the ultimate bad guys and unfortunately, they account for 90% of all air pollution. At 0.1 of a micron, they are the ninjas of pollution: invisible but able to be absorbed from your lungs into bloodstream and taken to your organs where they wreak havoc like heart attacks and strokes.
Anyone who suffers from seasonal hayfever will know all about the evils of pollen. The planet of course needs trees and plants to release their tiny grains to fertilise each other, but in a seeming failure of human evolution, our bodies sometimes overreact to the proteins in these tiny airborne male gametophytes, identifying them as foreign bodies worth attacking. We experience this defence as irritation in our eyes, nose and throat.
Pollen counts (measured by the amount of pollen in a cubic metre of air) can tell us when it’s best to stay indoors, but a “high pollen count” can be misleading because really it depends on the type of plant emitting the pollen. Generally though, symptoms appear when the count exceeds 50.
3. Mould (mold)
Instead of airborne grains, mould or fungi emit spores. These come in three varieties: allergenic, pathogenic, and toxigenic, causing allergies, infections and toxic responses respectively. Black mould is the one you hear a lot about in the media, as it has been to blame for recent deaths in poor housing conditions.
People may imagine black mould growing inside their lungs, but it is the mycotoxins released by the mould that cause catastrophic health problems, suppressing our immune responses. Wet floors, walls, and carpets, especially after flooding and in poorly ventilated homes, are susceptible to mould.
The advent of unleaded petrol helped to reduce airborne lead and it’s true that levels dropped by 94% in the USA in the 27 years after 1980. But lead-acid battery production has taken over as a source of lead in the air we breathe, causing severe damage to nearly all our bodily functions from our blood, to our nerves, our reproductive systems, our kidneys and our brains.
5. Volatile Organic Compounds (VOCs)
Right, I’ll just stay inside, you might think, but wait! Your walls, wallpaper and paints, furniture, and even your dry-cleaned clothing are all emitting gases that create indoor air pollution. Fine, you say, I’ll strip the wallpaper and paint, and tidy everything up.
Not so fast. Paintstrippers, cleaning fluids, disinfectants, pesticides, air fresheners and sprays – these all release VOCs too. They cause headaches, fatigue and allergies, irritation, damage to our bodily systems, and even cancer, in the case of formaldehyde.
6. Carbon Monoxide (CO)
This is one most of us are aware of. Every year, it seems, we hear not only about suicides by unvented car fumes, but also about tragedies where people have been rendered unconscious and killed in their own homes and holiday villas by CO poisoning from poorly maintained kerosene and gas heaters, furnaces, chimneys, and fireplaces.
This invisible, odourless threat is easily addressed with good maintenance and by installing (and regularly checking the batteries in) carbon monoxide detectors.
7. Ozone (O3)
We used to hear a lot about damage to Earth’s ozone layer and holes in it through which cancer-causing UV rays from the sun came, back in the 1980s. But it’s not just maintaining ozone in the upper atmosphere we need to worry about. Avoiding the creation of ozone at ground level is really important since exposure to it causes respiratory difficulties and infections, strokes and premature death. Cars, power plants, and refineries all emit chemicals that react with sunlight to become ozone, which we can even see as “smog”.
8. Nitrogen Dioxide (NO2)
You might smell smog and car pollution too and if you do, it’s probably NO2 you’re detecting – a sour-smelling gas caused by burning petrol and fossil fuels. It irritates the lungs and lowers our infection-resistance.
What’s more, NO2 molecules split in the sun and the resulting oxygen can form into ozone. NO2 is also the villain behind some particulates, as well as acid rain. Say no to NO2.
9. Sulphur (Sulfur) Dioxide (SO2)
Like NO2, SO2 is produced by fossil fuel burning, as well as aluminium smelting. It’s colourless but smells suffocatingly strong and can cause irritation, permanent lung changes and breathing difficulties, and death – even after short-term exposure.
The weirdly good news is that it is “almost exclusively manmade” processes, according to an Iqair explainer, that are responsible for SO2 emissions, so it is within our power as a species to do something about them.
10. What can I do?
It can seem overwhelming to realise the extent to which we are surrounded by natural and man-made pollutants, but you can do things as an individual. As well as driving, flying and consuming less, you can lobby your representatives, monitor air quality reports, install monitors and purifiers in your own home and car, and check the ingredients in the products you buy.