Table 7.

Risk of bias of on-site sampling studies of polymer NMP air pollution.

Study	Ethics	Funding	ROB Score (see below*)
Akhtar et al. [41]	Not applicable	Self-funded	2/3
Tang et al. [40]	None declared	Public: Shanghai 3-year Public Health Action Plan (GWV-10.1-XK11)	2/3
Rafiee et al. [39]	Approved by the University of Alberta ethics committee (Pro00103510)	Public: American Academy of Orthodontics Fund (AAOF BRA)	2/3
Lahdentausta et al. [38]	Approved by the local ethical committees of Helsinki University Hospital and the Helsinki City (HUS/1701/2020, HUS/1450/2020, HEL 2020–007596T130201)	Public: Suomen Naishammaslaakarit + Helsinki and Uusimaa Hospital District + Finska Lakaresallskapet + Rauha Ahokas Fund + Academy of Finland	2/3
Field et al. [37]	Approved by the Faculty of Science and Engineering Ethics Committee, reference number FEC_2020_106.	Public: Health Education England	3/3
Polednik [36]	None declared	Public: Polish National Science Centre under Grant NCN 7498/B/T02/2011/40)	3/3
Sotiriou et al. [35]	None declared	University funding	3/3
Henriks-Eckerman et al. [34]	None declared	None declared	3/3

	2022 Akhar	2022 Tang	2022 Rafiee	2022 Lahdentausta	2022 Field	2014 Polednik	2008 Sotiriou	2001 Henriks-Eckerman
Are the details of the sampling method described adequately?	Y	Y	Y	Y	Y	Y	Y	Y
Are the details of the analytical methodology described adequately?	Y	Y	Y	Y	Y	Y	Y	Y
Are the details of the calibration process for the analytic equipment adequately described?	N	N	N	N	Y	Y	Y	Y
	2	2	2	2	3	3	3	3

^{* ROB criteria.}