Table 1.

Size of the main particles likely to be inhaled.

Particles	Mean diameter	References
When calm expiration	0–500 μm	Xie 2009 [14], Tang 2013 [15]
When coughing	0–1500 μm
Grasses (Timothy grass)	30–40 μm	Crouzy 2016 [16]
House dust mite	22 ± 6 μm	Zhang 2019 [17]
Pollution		Lapuerta 2003 [18] Ezz 2015 [19]
PM10	< 10 μm
Fines	< 2,5 μm
Ultrafines	< 100 nm
Virus		CSG 2020 [3]
Rhinovirus	28–30 nm
Coronavirus	80–200 nm
Influenza A & B	80–120 nm
Syncytial Virus	150–400 nm