Overview and risks of different dust sizes.
The focus is on dust sizes and health risks: particle size determines dispersion, filterability, and health hazards. The smaller the particles, the deeper they penetrate the respiratory tract and the more difficult they are to remove. In industry, medicine, and everyday life, particles range from coarse dust to ultrafine aerosols—each class poses its own risks. Metal processing and medical laser procedures in particular produce very different size fractions, which should be specifically identified and evaluated. The following overview shows typical size ranges, examples, and health relevance.
| Particle size range | Typical particle examples | Comparison from everyday life | Notes on frequency & health |
| 10–27 μm | Larger lumpy particles (rare, outliers) | Fine grain of sand (approx. 25 μm) | Rare, especially in extremely high-energy laser operation |
| 1–10 μm | Coarse fine dust particles (few larger splashes) | Human hair: 60–100 μm (1–10 μm = 1/10 to 1/6 as thick as a hair) | Can settle, especially in the upper respiratory tract |
| 0,3–1 μm | Main mass of smoke particles (material cut) | Red blood cell: ~7–8 μm; pollen: 10–100 μm | Visible smoke, penetrates deep into the lungs |
| 0,1–0,3 μm | Largest proportion (fine/ultrafine) | Bacteria: ~1 μm; these particles are 1/10 to 1/3 as large | Penetrates into the alveoli, high health risk |
| 10–100 nm (0,01–0,1 μm) | Ultrafine particles (most numerous) | Coronavirus: ~0.1 μm | Extremely respirable, difficult to filter with masks |
Important comparisons for scale
- Human hair: 60–80 μm thick. Even the largest particles in laser smoke are usually only 1/10 to 1/1000 as wide.
- Pollen grain: 5–200 μm. The largest laser smoke particles just reach the lower end of this size range.
- Red blood cell: ~7–8 μm. Most laser smoke particles are significantly smaller.
- Typical bacteria: ~1 μm. The fine and ultrafine components of laser smoke are often even smaller.
- Viruses (e.g., coronavirus): ~0.1 μm. Many ultrafine smoke particles are comparably small.
- Coarse dust: greater than 10 µm
- Fine dust: less than 10 µm
- Ultrafine particles: less than 0.1 µm
Particle distribution in laser smoke
- Most common: Fine and ultrafine particles (0.1–1 μm) dominate in terms of number and mass, depending on the process.
- Smallest particles: Reach sizes around 10 nm (0.01 μm) – far below the filtration limit of normal masks.
- Largest particles: Approx. 27 μm, but very rare; more common in uncontrolled processes.
Note: The assessment of risks should always take into account the dust size health risks in order to select appropriate protective measures.
Sources:
Thin hair is stronger – wissenschaft.de
Erythrocyte – DocCheck Flexikon
Bacteria – Compact Encyclopedia of Biology + Bacteria | Federal Environment Agency
Viruses | Federal Environment Agency + Viruses at a glance – Infectious diseases – MSD Manual Professional Edition
