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Our next topic in the series of indoor air parameters is Particulate Matter (PM), or airborne particles. Airborne particles are a form of air pollution. Simply put, a particle is a piece of solid or liquid matter that floats in the air around us:

  • Gaseous contaminants (volatile organic compounds – VOC)
  • Particulate matter (viruses, bacteria, mites, allergens, fungal spores, pollen, radon, smoke)

VOC:s are quite a wide area, so we will dedicate a separate blog post for that shortly.

Different particle categories

These fine dust particles, or droplets, in the air vary from 1000 microns down to 1 microns or even less in width. To put it in context, there are about 10,000 microns in a cm. So, these “guys” are small!

Airborne particulate matter are usually categorised according to their diameter. PM10 is a particle below 10 µm, PM2.5 is below 2.5 µm across and PM1 is – unsurprisingly – less than 1 µm.

The most common particulate matters in the air are:

PM1 – particles <1 μm in size. Examples: dust, combustion particles, bacteria and viruses.
PM2.5 – particles <2.5 μm in size. Examples: pollen, mold spores and other organic particles.
PM10 – particles <10 μm in size. Examples: coarser fine dust and organic particles.
Coarse – coarse particles often 10 μm or larger. Examples: visible coarse dust, sand, leaves, hair and other organic particles.

Where do particles come from?

Airborne particles are created through nature’s own processes (volcanic eruptions, sandstorms, forest fires, plants’ pollen, etc.), but they are also created by man (when burning fossil fuels in vehicles, fireworks, fires, heating in heat and coal power plants, etc.).

We also create a lot of particles indoors. Indoor particles come from tobacco smoke, cooking (e.g. frying, sautéing, and broiling), burning candles and oil lamps, fire places etc. Particles are found everywhere, especially on carpets, stuffed toys, upholstered furniture, pillows, blankets and other beddings.

Particulate matter and health effects

It is important to understand the difference between these particle categories because they affect our health to varying degrees. When inhaled, PM10, PM2.5 and PM1 affect the body in different ways. Their ability to get stuck in the body where they can form depots depends on their size and whether they can pass through the mucous membranes of the airways. With the help of our nose hairs, particles around 100 µm across are prevented from penetrating our bodies. However, smaller particles travel further in:

  • PM10 gets stuck in the throat
  • PM2.5 gets stuck in the lungs
  • PM1 enters the lungs, passes through the membrane system of the alveoli, enters the bloodstream and can damage the inner walls of the arteries, further into the tissue of the cardiovascular system, where it can spread to other organs.

There has been a lot of focus on PM2.5 until now. These particles are dealt with by the lungs, and from there can be absorbed into the bloodstream. But new research indicates the smallest particles could be the most dangerous and can cause serious health effects. People with breathing- and heart problems, children and the elderly could be particularly sensitive.

So what kind of health effects are we talking about?

Dust levels above 100 microns/m3 may cause some short-term health effects such as eye-, nose-, throat- and lung irritation, coughing, sneezing, runny nose and shortness of breath. If you have chronic respiratory conditions such as asthma, rhinitis or bronchiolitis and dust is one of the things you’re sensitive to, particles can affect your lung function and worsen your asthma.

What can be done about it?

If you are sensitive, make sure that your home is kept clean and dust free. Also vacuum your carpets, stuffed furniture, pillows, blankets and beddings. Remember to check your child’s stuffed toys for dander or dust mites. These could be the ones causing his/her respiratory conditions. You may also consider buying an air purifier with HEPA filters.

If you have a ventilation system a majority of the particles from outside can be removed. Make sure to have a good quality HEPA filter.

Wrapping up

I’d like to wrap it up with a small tip. Personally, I use a lot of candles in the autumn and winter time. And I’m not the only one – in Sweden we burn 46 000 tons of candles every year. That’s quite a lot…

I would recommend to always use candles made of 100% stearin. Paraffin candles are made of fossil material and they emit large amounts of carbon dioxide when they burn. Another problem with candles is that they emit particles. Above all, it is harmful soot particles to watch out for. In 2014, the Norwegian Public Health Institute issued a warning comparing the harmful effect of soot particles from heat lamps with passive smoking.

If you are really interested in knowing what is in your indoor air, there are many different types of sensors and monitors on the market. Just search for air quality sensors, or –monitors and the results will start popping up. Don’t hesitate to contact us for tips!

As always I would like to round up by reminding you to, drop us a line or give us a call if you want to give us input on other interesting topics to cover. Or discuss our passion – indoor air. You can find other interesting posts if you dif deeper into our blog.