Table 1.

Total number concentrations of five PM fractions (nano to 10 µm) per cm³ measured by on-line monitoring (SMPS and APS) during the shift related to the individual working processes including backgrounds.

	Total Number Concentrations of PM Fractions per cm3
Processes	1.	2.	3.	4.	5.	Total
Backgrounds	<25 nm	25–100 nm	100 nm–1 µm	1−2.5 µm	2.5−10 µm	<10 µm
MAG welding	1680	3840	3790	1.1	0.215	9311
Grinding and Milling	9700	16400	3040	16	2.53	29159
Background, basement	574	6260	2370	0.42	0.078	9204
Background, ground floor	92.5	3550	1680	0.232	0.006	5323

Abbreviations: SMPS, scanning mobility particle sizer; APS; aerodynamic particle sizer; MAG, metal active gas.