Table 4.

Changes in estimated variance components from the random-effects modela to the mixed-effects models.

PAH	Model 1: random effects, no covariates			Model 3: mixed effects, neighborhood covariates		Model 4: mixed effects, residential covariates		Model 5: mixed effects, temporal covariates		Model 6: mixed effects, all covariates
	σ2BR	σ2BH	σ2WH	σ2BR	%BR	σ2BH	%BH	σ2WH	%WH	σ2BR	%BR	σ2BH	%BH	σ2WH	%WH
Phenanthrene	0.01	0.13	0.26	0	100	0.13	5	0.26	–1	0	100	0.13	5	0.27	–3
Anthracene	0.01	0.14	0.32	0.005	68	0.13	5	0.31	3	0.002	86	0.14	3	0.31	2
Fluoranthene	0.03	0.26	0.27	0.02	14	0.20	22	0.27	0	0.01	59	0.20	23	0.27	–3
Pyrene	0.02	0.15	0.26	0.01	63	0.12	17	0.26	2	0.005	75	0.12	16	0.26	0
Benzo[a]anthracene	0.04	0.33	0.47	0.02	52	0.24	25	0.47	–1	0	100	0.24	28	0.48	–4
Chrysene	0.03	0.23	0.31	0.02	33	0.17	27	0.31	–1	0.002	90	0.17	27	0.31	–3
Benzo[b]fluoranthene	0.04	0.34	0.34	0.02	56	0.27	20	0.33	2	0	100	0.26	22	0.34	0
Benzo[k]fluoranthene	0.04	0.37	0.36	0.03	18	0.30	19	0.34	5	0.004	89	0.30	19	0.35	3
Benzo[a]pyrene	0.06	0.37	0.43	0.02	65	0.31	18	0.42	3	0	100	0.29	22	0.43	1
Indeno[1,2,3-c,d]pyrene	0.06	0.35	0.40	0.01	77	0.30	16	0.37	9	0	100	0.29	19	0.37	8
Dibenzo[a,h]anthracene	0.05	0.27	0.42	0.01	86	0.23	16	0.36	15	0	100	0.24	13	0.36	14
Benzo[g,h,i]perylene	0.06	0.24	0.29	0.001	98	0.21	12	0.27	6	0	100	0.19	22	0.27	6
Abbreviations: σ2BR, between-region variance; σ2BH, intraregional between-household variance; σ2WH, within-household variance over time; %BR, percent of between-region variance from the random-effects model (model 1) explained by the neighborhood covariates (i.e., ambient PAH from area and mobile sources) included in the mixed-effects model (model 3 or 6); %BH, percent of intraregional between-household variance from the random-effects model (model 1) explained by the residential covariates (i.e., reported smoking, residence construction date, apartment is residence, shoe removal, carpet coverage, residential square footage, and combustion-based heating) included in the mixed-effects model (model 4 or 6); %WH, percent of within-household variance over time from the random-effects model (model 1) explained by the temporal covariates (i.e., interview and laboratory analysis dates) included in the mixed-effects model (model 5 or 6). PAHs are ordered by molecular weight from lightest to heaviest. aModel 1 and models 3–6 were fit for 451 observations including 405 samples collected from 204 homes during repeat sampling rounds and 46 duplicate samples, and excluding 139 observations without covariate data (40 interbatch quality control replicates and 89 samples with 10 duplicates from homes that were sampled during round 1 only).