Table 3: Mean (SD) of concentration (mg/m3) of various metal fumes produced during various types of welding
Fumes	SMAW*	GMAW†	FCAW‡	TLV-TWA§	p value
Cr	1.11 (0.33)	3.75 (1.55)	0.42 (0.07)	0.5	0.02
Mn	2.37 (0.64)	2.93 (0.70)	1.17 (0.39)	0.2	0.41
Z	1.08 (0.45)	1.76 (0.59)	0.93 (0.32)	5.0	0.09
Cu	0.23 (0.05)	0.44 (0.16)	0.18 (0.06)	0.2	0.61
Fe	5.43 (1.10)	7.50 (2.85)	3.22 (1.66)	5.0	0.01
Al	4.29 (1.63)	5.52 (1.10)	2.47 (0.89)	5.0	0.16
Total fume	5.88 (2.11)	9.04 (3.20)	4.84 (1.50)	5.0	0.05
*Shielded metal arc welding; †Gas metal arc welding; ‡Flux cored arc welding; §Threshold limit value-time weighted average