Mesenchymal Stem Cells as Therapeutics Agents: Quality and Environmental Regulatory Aspects

Table 3

Airborne particulate classification for these grades, according to the PIC/S GMP and EU-GMP.

Grade	Maximum number of particles permitted/m^3
	At rest		In operation
	≥0.5 µm	≥5.0 µm	≥0.5 µm	≥5.0 µm
A	3,520	20	3,520	20
B	3,520	29	352,000	2,900
C	352,000	2,900	3,520,000	29,000
D	3,520,000	29,000	Not defined	Not defined

All areas must be free particles of size greater than 5 μm. Limits are set to 1 particle/m³ because it is impossible to ensure the absence of particles with any statistical significance. The periodic classification of facilities (cleanroom) must show that all areas meet the defined limits.