Exposure of laboratory animals to small air ions: a systematic review of biological and behavioral studies

Table 1 Summary of quality ratings of studies reviewed

Topic	Number of studies^a	Number of studies in compliance with quality indicators^b
Topic	Number of studies^a	Shamcontrol	Confounding^bc	Blinding	Randomized	Individual exposure
Behavior	13	12	6	4	4	6
Learning and memory	9	4	2	1	5	3
Serotonin and other neurotransmitters	13	6	2	4	6	4
Tracheal function	7	6	2	0	0	3
Respiratory infection	5	4	1	0	2	0
Cardiovascular measures	5	4	0	0	0	5
Reproduction and growth	11	8	3	0	3	1
Carcinogenesis	2	1	0	0	1	1
Other endpoints	4	2	1	0	1	1
Totals (%)	69	47 (68%)	22(35%) (32%)	9 (13%)	22 (32%)	24 (35%)

^aSome of the 62 studies reported results in more than 1 topic area
^bSome studies that did not generate air ions by corona discharge were not susceptible to major confounding factors
^cMinimal compliance was indicated if any confounding factor, electric field, ozone, noise, or light was addressed

ISSN: 1475-925X