What is PM2.5 and why does it matter?

PM comes from both natural and human sources

Particulate matter (PM) is a type of particle made up of solid or liquid droplets found in the air. These particles are also sometimes referred to as aerosols. They come from both natural and human sources, like fields, fires, dirt roads, and construction sites. Many particles form in the air as a result of complex reactions caused by chemicals in the atmosphere from sources like power plants, factories, and vehicles.


PM2.5 has the diameter of 2.5 microns or less

Some PM particles are big enough or dark enough to be seen by the human eye, but others are much smaller and can only be seen with a microscope. There are two types of PM that are usually measured: PM10, which are particles with a diameter of 10 microns or less, and PM2.5, which have a diameter of 2.5 microns or less.

PM2.5 particles are even smaller than the diameter of a strand of human hair (50-70 microns) or a grain of fine beach sand (90 microns). This is partly why these particles are so dangerous: they are easily inhalable and extremely hard to filter out of the air we breathe. Our noses cannot filter PM2.5, and even most face masks have difficulty doing so because the particles are so small.


PM2.5 can penetrate our lungs and bloodstream, causing serious health problems  

PM2.5 particles can cause serious health problems. They can get deep into our lungs and be absorbed in our bloodstreams. This is dangerous because PM2.5 is made up of toxins like nitrates, sulphates, heavy metals, and other chemicals.

Health problems can occur after both short-term and long-term exposure to PM2.5. Numerous scientific studies have shown links between exposure to PM2.5 and increased hospital admissions as well as death from heart and lung diseases.

The amount of PM2.5 in the air is an important measure of air pollution. The less PM2.5 there is, the healthier the air. Unfortunately, there is currently no evidence of a threshold below which exposure to PM does not cause any health effects, which is why it is crucial to get PM2.5 levels as low as possible.

PM2.5 is very bad for our health, so it is important we understand the impacts it can have.