Why high PM levels should be taken seriously
August 2023 • 2 min read
High Particulate Matter (PM) levels affect our health in many ways ... and the majority of big cities already suffer unhealthy PM levels. PM10 refers to coarse, larger particles with a diameter of less than 10 microns, but generally excludes fine particles. An example of PM10 is dust from roads, farms, dry riverbeds and contruction sites which, when inhaled, is generally limited to the upper airways. The bigger danger is PM2.5, or fine particles with a diameter of less than 2.5 microns. These can go deep into the lungs and even enter the bloodstream, from where they can enter tissues and organs around the body and remain there for months.
What are the main sources of PM 2.5 and PM10?
Main sources are natural (bushfires, dust, pollen etc.) and manmade (diesel, coal and biomass combustion as well as smoking), which is the most hazardous to health.
The biggest driver of indoor PM concentration is its outdoor air concentration, which tends to go up in cold months.
How do high PM levels affect our health?
Effects: When inhaled, PM10 is limited to the upper airways whilst PM2.5 can go deep into the lungs and enter the bloodstream. It then spreads around the body and enters tissues and organs, where the particles remain for months.
When PM is introduced inside the human body, our white blood cells recognise it’s a foreign object and attack it. The accumulation of white blood cells at any site where PM is present leads tointracellular swelling, which in turn leads to significantly reduced total lung capacity, thus affecting oxygen blood saturation. It is associated with multiple respiratory diseases including chronic obstructive pulmonary disease, pulmonary sclerosis, asthma and lung cancers.
High PM levels are associated with casrdiovascular problems
Similar effects are observed when PM deposits in the lining of blood vessels – the walls of small arteries swell up, vascular smooth muscle cells contract (causing the internal diameter of the blood vessel in question to narrow), all of which promotes the formation of clots and plaque inside. Over time, this can completely cut off oxygen supply to organs and tissues. PM2.5 exposure is linked to a higher risk of ischemic heart disease, stroke, atherosclerosis, hypertension, heart attack and heart failure.
