. Author manuscript; available in PMC: 2013 Mar 11.

Published in final edited form as: Atmos Environ (1994). 2009 Jun 12;44(7):987–998. doi: 10.1016/j.atmosenv.2009.06.006

Table 1.

Species with statistically significant weekday/weekend mean differences.

Species	Weekday mean^a	Weekend mean^a	Percent change^b	Lower 95% CI^c	Upper 95% CI^c	P-value^c
EC	0.61	0.41	−33	−38	−27	<0.0001
22s-ab-30-Homohopane	0.10	0.07	−28	−40	−17	<0.0001
Benzo[ghi]fluoranthene	0.10	0.08	−28	−43	−12	0.0006
ba-30-Norhopane	0.38	0.28	−27	−38	−16	<0.0001
ab-Hopane	0.24	0.17	−27	−39	−16	<0.0001
22r-ab-30-Bishomohopane	0.05	0.04	−26	−38	−15	<0.0001
20r-abb & 20s-aaa-Cholestane	0.15	0.12	−25	−34	−16	<0.0001
a-22,29,30-Trisnorhopane	0.09	0.07	−25	−34	−16	<0.0001
22s-ab-30-Bishomohopane	0.06	0.05	−25	−37	−12	0.0002
Pyrene	0.17	0.13	−25	−42	−7	0.0054
20r & s-abb-Ethylcholestane	0.12	0.09	−24	−34	−14	<0.0001
Methyl-202-pah sum	0.66	0.50	−24	−42	−7	0.0068
20r & s-abb-Methylcholestane	0.11	0.08	−23	−35	−11	0.0003
22r-ab-30-Homohopane	0.07	0.06	−23	−37	−9	0.0013
Benz[a]anthracene	0.06	0.05	−23	−44	−3	0.0244
Chrysene/triphenylene	0.18	0.14	−21	−35	−6	0.0053
Coronene	0.11	0.08	−21	−37	−4	0.0146
1,8-Naphthalic anhydride	0.33	0.26	−20	−30	−11	<0.0001
Benzo[ghi]perylene	0.22	0.18	−19	−37	−1	0.0396
Fluoranthene	0.20	0.17	−18	−34	−3	0.0175
Methyl-228-pah sum	0.12	0.10	−17	−33	−2	0.0263
TC	3.69	3.44	−7	−11	−2	0.0026
Hexadecanoic acid	16.95	20.91	23	6	41	0.0102
Nonatriacontane	0.14	0.18	29	3	56	0.0300
Octadecanoic acid	10.43	13.41	29	7	50	0.0091
Heptadecanoic acid	0.56	0.77	36	13	58	0.0019
Acetovanillone	0.52	0.72	39	6	72	0.0219
Coniferaldehyde	1.07	1.56	46	4	87	0.0305
Syringaldehyde	1.05	1.59	52	9	95	0.0189

EC and TC are in μg m⁻³; all other species are in ng m⁻³.

Percent change from the weekday mean to the weekend mean (negative values indicate a weekend decrease; positive values indicate a weekend increase.

Results froma two-sided t-test comparing weekday mean toweekend mean allowing for unequal variances (only species showing a significant difference at the 95% confidence level are included and are sorted by the percent change). The upper and lower 95% confidence intervals (CI) are displayed as a percent change from the weekday mean.