Table 1.

Descriptive statistics for toxicant and dust loadings before and after cleaning

	Pre-cleaning		After HEPA–HEPA cleaning		After HEPA–steam– HEPA cleaning
Carpet contaminantsa	Nb	GMc	Nb	GMc	Nb	GMc
Naphthalene	44	0.024	42	0.012	41	0.012
Acenaphthylene	29	0.003	12	0.001	12	0.001
Acenaphthene	32	0.010	28	0.005	24	0.005
Fluorene	36	0.014	35	0.006	36	0.006
Phenanthrene	47	0.250	47	0.116	43	0.086
Anthracene	42	0.030	30	0.024	31	0.016
Fluoranthene	47	0.409	48	0.194	43	0.156
Pyrene	47	0.333	48	0.173	44	0.126
Benzo[a]anthracene	47	0.106	44	0.050	37	0.042
Chrysene	47	0.123	45	0.058	38	0.054
Benzo[b]fluoranthene	45	0.099	39	0.042	33	0.053
Benzo[k]fluoranthene	45	0.084	37	0.038	31	0.048
Benzo[a]pyrene	42	0.077	31	0.045	30	0.036
Indeno[1,2,3-cd]pyrene	34	0.054	27	0.027	22	0.034
Benzo[g,h,l]perylene	28	0.021	19	0.021	16	0.016
Dibenz[a,h]anthracene	40	0.050	27	0.029	25	0.032
Total PAHsd	49	1.57	50	0.66	48	0.45
HDM allergens	15	2.41	15	0.46	15	0.35
Dust	50	1.00	50	0.44	50	0.35

^aThe unit of loading is µg ft⁻² for PAHs and HDM allergens and g ft⁻² for dust.

^bN=the number of samples.

^cGM = geometric mean.

^dThe sum of all sixteen PAHs analysed in the study.

See Methods for a description of the HEPA–HEPA and HEPA–steam–HEPA cleaning protocols.