Air. If you are reading this on planet earth, then you are surrounded by it. Air is synonymous with the words ‘invisible’ ‘nitrogen’ and ‘oxygen’, but that isn’t the whole picture. If you are outdoors, you can be sure there are tiny physical particles in the air you are breathing. They are many times smaller than the diameter of a human hair, and unseen by the naked eye. These particles are known as particulate matter, or PM.
Don’t believe it? It’s easy to understand when you think about visible PM; a cloud of dust, or smoke from a campfire for example. How come we can see those? These are examples of high concentrations of PM, and there are often some larger more visible particles mixed in. Now think about these particles rising up and dispersing in all different direction until they are invisible again. The larger these particles are, the quicker they drop to the earth; conversely, the smaller the particles are, the slower they fall. If the particles are small enough, they will actually float in the air for hours. Have you ever seen a cotton fiber floating around your house? A simple wave of your hand will send it shooting up higher and higher into the air. While outdoors, these particles can be blown for miles on gusts of wind.
So why does Particulate Matter matter? Unfortunately the smaller these floating particles are, the worse they are for human health. In fact, Particulate Matter affects more people than any other pollutant*. Particles that are smaller than 10 micrometers (PM10) in size can enter your nose and make it down your airway, into your lungs. These are also known as ‘inhalable particles’. Anything larger will get trapped trying to find its way down, or get caught by nasal hairs (a good reason to breathe through your nose rather than your mouth).
You may have heard of a type of air pollution called PM2.5. This is particulate matter that is 2.5 micrometers in size or smaller, nicknamed ‘respirable particles’. Why is there so much focus on it? Not only does PM2.5 have a much better chance of reaching the lungs, but it also on average consists of more harmful particles. Yes, the type of particle matters too, it could even be coated by toxins.
So what types of particles make up PM? The majority consists of sulfate, nitrates, ammonia, sodium chloride, black carbon, mineral dust and water. Black Carbon is an aspect of PM that is often talked about because of its affect on humans. It comes from the incomplete combustion of fossil fuels, biofuels and biomass. One important-to-note source of Black Carbon comes from Diesel Engines, commonly found in our vehicles. Wood-burning stoves, open-burning and campfires have become controversial topics over the last few years.
So what’s the big deal, how does this affect you, personally? In March 2014, The World Health Organization released some shocking statistics, which showed that they had grossly underestimated the amount of deaths and pre-mature deaths caused as a result of this Air Pollution. In 2012, it was estimated that 7 million people died from ischaemic heart disease, strokes, chronic obstructive pulmonary disease, acute lower respiratory infections, and lung cancer. Yes, even lung cancer.
“A 2013 assessment by WHO’s International Agency for Research on Cancer (IARC) concluded that outdoor air pollution is carcinogenic to humans, with the particulate matter component of air pollution most closely associated with increased cancer incidence, especially cancer of the lung.”
There are some 3 billion people who cook and heat their homes with biomass fuels and coal, are you one of them? Here is one more reason why Particulate Matter matters: reducing PM would also reduce short-lived climate pollutants such as black carbon particles, therefore reducing the effects of climate change. It’s time to think differently about the air we breathe.
World Health Organization