PM2.5 refers to a mixture of particles with a diameter of fewer than 2.5 micrometers, which is about 30 times smaller than the width of a human hair.
We are particularly vulnerable to these nano-particles as they reach the alveoli in our lungs to enter the bloodstream. As it bypasses our body’s defense mechanisms, even a tiny amount of PM2.5 has a disproportionate effect on health than any ingested poisons.
Where does it come from?
PM2.5 particles are more complex than PM10. Natural, partial liquid, aerosols can come from dust, sea salt, and volcanic ash. Man-made sources include emissions from power plants, factories, and vehicles, coal combustion, and biomass burners.
Secondary PM2.5 particles are created when chemicals combine in the air and react with sunlight to form new compounds. There are so many variables it’s impossible to identify which are present at any one time.
What are its effects?
For many people, there is no safe limit of PM2.5. Children living around high levels of PM2.5 have slower lung development and it is a known contributor to cardiovascular and respiratory diseases, severe asthma attacks, and premature death.
In addition, long-term exposure to fine particulate matter was associated with an 8% increase in Covid-19 mortality rate on average.