Table 1.

Environmental strategy categories of the trials studied by Gøtzsche and Johansen37

Trial	Author	Year	Strategy	Barriers	Remark
1	Antoniceli	1991	Air purification	NA
2	Bahir	1997	Concurrent bedroom	1
3	Burr	1980A	Concurrent bedroom	1
4	Burr	1980B	Concurrent bedroom	1
5	Carswell	1996	Concurrent bedroom	3
6	Chang	1996	Concurrent bedroom	1
7	Chen	1996	Concurrent bedroom	1
8	Cinti	1996	Concurrent bedroom	1	Strategy extracted from description by Gøtzsche and Johansen
9	Cloosterman	1999	Concurrent bedroom	2
10	De_Vries	2007	Concurrent bedroom	1
11	Dharmage	2006	Concurrent bedroom	1
12	Dieteman	1993	Concurrent bedroom	1
13	Dorward	1988	Concurrent bedroom	1
14	Ehnert	1992	Concurrent bedroom	2
15	Fang	2001	Concurrent bedroom	1
16	Geller‐Bernst	1995	Concurrent bedroom	1
17	Halken	2003	Concurrent bedroom	1
18	Htut	2001	Concurrent bedroom	1
19	Huss	1992	Concurrent bedroom	1
20	Kroidl	1998	Concurrent bedroom	1
21	Maesen	1977	Air purification	NA
22	Marks	1994	Concurrent bedroom	2
23	Reiser	1990	Concurrent bedroom	1
24	Rijssenbeek	2002	Concurrent bedroom	3
25	Sette	1994	Concurrent bedroom	1
26	Shapiro	1999	Concurrent bedroom	2
27	Sheikh	2002	Concurrent bedroom	1
28	Thiam	1999	Concurrent bedroom	2
29	Van_der_Heide	1997A	Concurrent bedroom	1
30	Verrall	1988	Air purification	NA
31	Walshaw	1986	Concurrent bedroom	1
32	Warburton	1994	Air purification	NA
33	Warner	1993	Air purification	NA
34	Woodcock	2003	Concurrent bedroom	1
35	Wright	2009	Concurrent bedroom	1
36	Zwemer	1973	Air purification	NA