Harmful aerosol particles from near and far

Right now we are horrified by the thought of aerosol particles from nuclear fallout. There are other harmful particles coming from afar, and you should protect yourself from all of them. The size of the aerosol particles affects how far they travel in the air. The size also affects how deep the particles end up in the respiratory system. In addition, the size determines how easy or difficult it is to filter the aerosol out of the air.

In general, you could say that the smaller the particle, the further and longer it flies in the air, whether we are looking at the atmosphere, our lungs or the particle filter. In reality, however, there is an aerosol size that is the most permeable and volatile. This size is about 0.1 micrometer (μm) or 100 nanometers or one ten-thousandth of a millimeter. As the size continues to decrease, the aerosol no longer stays in the air for as long.

However, small size does not make nanoparticles any less harmful. This ultrafine (ultrasmall) size class can even reach our brain to cause Alzheimer's. The smallest particles are always formed in combustion processes and their number is greatest near the fire site.

Why are the particles from nuclear fallout or, for example, forest fires in Russia worrying? In addition to its composition, of course. They are exactly the size category that travels in the atmosphere for days, even weeks, gets deep into the respiratory system and requires a proper filter to filter them.



Previously, after the Chernobyl accident and most recently the Fukushima accident, scientists worked hard to find out what size particles were transported to different parts of the globe and in which size classes radioactive isotopes were observed. The findings were very similar in both.

One scientific publication reports on Fukushima fallout studies from France, Austria, the Czech Republic, Poland, Germany, and Greece. According to the study, most of the particles were in the size range 0.1-1 μm and the median size class Cesium (137) was 0.25 - 0.71 μm, Cesium (134) was 0.17 - 0.69 μm and Iodine (131) was 0.3 - 0.53 μm.

In addition to aerosol particles, nuclear fallout also contains radioactive gases. Iodine gas can be filtered with ordinary activated carbon (elemental iodine) or impregnated activated carbon (compounds of iodine).

A well-fitting FFP3 respirator filters more than 97% of all these size categories (The protector is classified for 0.6 μm particles, for which the filtering efficiency is 99%).

An air purifier equipped with a HEPA filter significantly reduces the number of harmful aerosols in the indoor air. HEPA filters are tested with the most permeable particle size. There are several HEPA classes, but even the lowest of them filters the most permeable particle size by more than 95%. Several Lifa air purifiers also have an active carbon filter.


Every year, people worldwide suffer from long-distance travel caused by forest fires. We also have forest and other extensive fires in Finland every year. The particles from forest fires don't sound as scary as the particles from nuclear fallout, but the probability of inhaling them is much higher. All combustion-derived particles are harmful and most of them are very small. It is also good to protect yourself against particles from forest fires with FFP3 respirators and air purifiers.

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Air purifiers

Size Distributions of Airborne Radionuclides from the Fukushima Nuclear Accident at Several Places in Europe. Masson et al. Environmental Science & Technology 2013, DOI: 10.1021/es401973c

Particle size distribution of radioactive aerosols after the Fukushima and the Chernobyl accidents. Mala et al. Journal of Environmental Radioactivity, 2013, https://doi.org/10.1016/j.jenvrad.2013.07.016