Table 2. Repeated measurements in 13 school buildings (all location types).

		Winter 2009		Spring 2009		Winter 2010		Correlationbetween winterand spring 2009		Correlationbetween winter2009 and 2010
	N	Geom.mean	Geom.SD	Geom.mean	Geom.SD	Geom.mean	Geom.SD
		(ng/m2/week)		(ng/m2/week)		(ng/m2/week)		r	p	r	p
HDM	117	177.7	2.249	140.8*	2.588	92.1*	2.404	0.503	<0.001	0.508	<0.001
β-glucans	126	1313	1.950	1281	1.923	1075*	1.862	0.568	<0.001	0.607	<0.001
Fel d 1	99	49.7	1.866	50.2	2.080	67.8*	1.950	0.637	<0.001	0.268	0.007
Can f 1	89	31.8	2.004	17.4*	2.046	48.9*	1.945	0.586	<0.001	0.450	<0.001
Mus m 1	130	Not done		0.76	4.699	1.20*	3.784	0.686†	<0.001

* Significantly different (p≤0.002) from winter 2009 or (for Mus m 1) from previous measurement.

^†Correlation between the 2 measurements (spring 2009 and winter 2010).