Table 3. Median ACH, range and number of measurements that are above the WHO recommendation for each room, comparing window only and turbine and grate only.

	Room 1	Room 2	Room 3	Room 4	Total(all rooms)
WHO recommended ACH	10.0	6.7	7.4	6.5
Window only (scenario 2)
Number of experiments	51	5	26	24	106
Median ACH	8.1	3.7	7.3	11.4	8.5
IQR	6.2–10.1	2.7–4.8	3.5–11.2	7.2–15.7	5.5–11.5
Range	2.1–29.6	2.0–4.6	1.3–16.4	2.4–24.8	1.3–29.6
No. above WHO recommendation	15 (29%)	0 (0%)	13 (50%)	20 (83%)	48 (45%)
Turbine and grate only (scenario 3)
Number of experiments	43	7	23	22	95
median ACH	8.9	13.5	16.7	13.4	11.3
IQR	5.8–12.0	10.6–16.4	9.4–24.1	8.0–18.9	7.2–15.4
Range	3.2–21.6	9.2–17.2	8.4–30.0	6.3–37.7	3.2–37.7
No. above WHO recommendation	20 (47%)	7 (100%)	23 (100%)	21 (95%)	71 (75%)
Comparison between scenarios 2 and 3
P value (comparison of medians)	0.28	0.004	<0.000	0.07	<0.000
P value (comparison of proportion above WHO recommendation)	0.09	0.004	<0.000	0.40	<0.000
% Contribution of roof turbine to ACH* (95% CI)	71 (64–78)	61 (48–75)	49 (43–55)	40 (36–43)	58 (53–62)

*Calculated by using the measurement of actual flow through the turbine, at the same time as overall ACH measurement.