Table 1.

Characteristics of studies using the Index of Microbial Air contamination (IMA) standard

Country Publication year (Ref)	Study setting	Sampling period	N. of monitored environments	Sampling time/ condition	Bacteria (IMA)		Fungi (IMA)		Microbial Total Count (IMA)
					Mean (SD)/mean range/median	Range	Mean (SD)/mean range/median	Range	Mean/mean range/median
Indoor environments
Cultural heritage
Italy 2011 (18)	Museum	January	7 rooms	before opening time	2.86*	1* - 7*	0.45*	0* - 2*
				during opening time	11.51*	3* - 21*	0.89*	0* - 3*
Italy 2012 (19)	Library	April	8 rooms			0* - 31*		0* - 3*
Italy 2014 (20)	Museum	May	3 rooms	during opening time				1 - 48○
		October						0 - 10○
Italy 2015 (21)	Library	July	1 room		8	3 - 35	1	0 - 3
		December			8	4 - 15	2	0 - 3
Italy 2015 (22)	Library	Spring	1 room				0 - 28*
Nigeria 2018 (23)	Library	Rainy season			7 (2) - 30 (3)		22 (3) - 73 (4)
		Dry season			5 (3) - 22 (4)		13 (2) - 27 (5)
Italy 2019 (24)	Library	February	1 room		3.33	0 - 7	0.5	0 - 2
		May			3.33	1 - 6	3.67	0 - 9
		September			3.33	0 - 5	4.33	1 - 9
		December			1.33	0 - 3	0.67	0 - 2
Educational Buildings
Italy 2009 (26)	University	April - June	14 rooms Buildings A, B, C Research laboratories	in the morning (m.) in the afternoon (a.)					A m. 1.1 - 41.8 a. 0.1 - 6
									B m. 0.5 - 3.8 a. 0.5 - 4.3
									C m. 1.1 - 20.3 a. 0.7- 29
		October - December							A m. 0 - 11 a. 0 - 45
									B m. 2.1 - 5.7 a. 0.5 - 4.2
									C m. 1.3 - 17 a.0.5 - 10.3
Malaysia 2017 (27)	University		5 environments	in the morning (m.) in the afternoon (a.)
			University Service Center		m. 12.08* a. 5.09*
			Top Management Office		m. 5.72* a. 3.81*
			Tissue Culture Laboratory		m. 6.99* a. 17.8*
			Cafè		m. 22.25* a. 15.26*
			Library		m. 27.98* a. 27.98*
Other environments
Turkey 2011 (28)	Morgue Department	Spring - Summer	1 autopsy room	before autopsy	Spring 9.1 (5.7)		Spring 2.7 (1.7)
					Summer 27.4 (22.1)		Summer 16.7 (26.3)
				during autopsy	Spring 51.1 (17.1)		Spring 117.8 (271.6)
					Summer 60.9 (65.7)		Summer 99.3 (175.6)
				after autopsy	Spring 21.6 (49.3)		Spring 13 (28.4)
					Summer 19.7 (21.6)		Summer 9.2 (10.5)
South Africa 2017 (29)	Fruit handling environments	Over three years period	11						27 - 900• 105•
Japan 2019 (30)	Animal housing system	November - January	1		0.3•		9.3•
Indoor and outdoor environments
Norway 2009 (34)	Dry-cured meat production facility	February, August, December	16 rooms indoor outdoor	operational			15
Iran 2014 (32)	School dormitory	One year period	1			indoor 10 - 112		indoor 11 - 36
	and retirement home		1			outdoor 15 - 96		outdoor 8 - 40
Thailand 2016 (33)	Fitness centre A (indoor)				2.09 (1.50)		0.97 (1.69)
	Fitness centre B (indoor)		3		8.44 (5.74)		5.07 (2.34)
	Fitness centre C (outdoor)				7.52 (3.73)		5.59 (3.57)
Italy 2017 (31)	Buffalo farms			at rest			10 - 76
			3 Feeding rooms (outdoor)	operational			39 - 76
				at rest			6 - 76
			3 Milking rooms (indoor)	operational			12 - 24
Egypt 2020 (25)	Museum	Two years period	6 Buildings	working hours				1 - 256**
Outdoor environments
Malaysia 2015 (35)	Residential areas: Case study:		2
	built on dumping site				48•		36•
	Control: at 20 km from				27•		36•
	case study
Israel 2016 (36)	Areas closeness to domestic GW-treatment systems (RVFCWs)	June - February	3	early in the morning
				0.3 m away from GW-t systems	0.22 - 616.7**
				1 m away from GW-t systems	0 - 15.2**
Vietnam 2019 (37)	Ho Chi Minh City	Three years period	4	four times a day
			road area		80.3**		4.37**
			zoo area		33.3**		52.48**
			residential area		42.26**		3.02**
			rural area		99.27**		14.17**
Legenda: *calculated from CFU/dm2/h; **calculated from CFU/m2/h; • IMA calculated for 1 h; ○only fungal count on Saburand Dextrose Agar medium was considered