Table 12.

Ratios of Mean Downwind and Upwind Pollutant Concentrations by Terminal

Terminala	EC	OC	PM2.5	Butadiene	Benzene	Formaldehyde	Acetaldehyde
Oklahoma City (23)	0.29	0.57	0.37
Columbus (24)	0.42	0.64	1.35		0.86	0.66	2.33
Milwaukee (25)	1.09	1.02	0.78	0.88	1.00	0.93	1.26
Memphis (26)	1.14	1.22	1.23		0.85	0.71	1.84
Phoenix (27)	0.80	1.25	—		0.72	2.67	1.88
Portland (28)	—	0.98	1.17		0.76	1.05	1.90
Denver (29)	1.58	1.18	1.44		1.35	1.34	1.06
Miami (30)	0.94	1.07	0.52		1.13
Hagerstown (31)	0.93	1.40	1.58	0.71	0.82	0.65	0.58
Nashville (32)	0.72	0.82	0.64	1.11	0.84	0.98	0.94
Middletown (33)	0.93	0.84	1.53	0.56	1.11	1.16	1.36
Laredo (35)	1.20	0.92	1.10	0.89	1.01
Philadelphia (36)	1.12	1.17	1.03	1.39	1.76	1.25	0.93
Repeat-Visit Terminals
Philadelphia (37)	1.31	1.21	1.12	3.22	2.25	1.42	1.11
Columbus (38)	0.55	0.88	0.79	0.47	0.74	0.78	0.85
Milwaukee (39)	1.50	1.39	1.25
Phoenix (40)	1.08	0.88	1.18	0.91	0.82	0.84	0.80
Denver (42)	2.93	1.07	1.20	1.18	1.63	1.11	0.68
All Visitsb
Mean	1.03	1.03	1.02	1.13	1.10	1.11	1.25
SD	0.62	0.23	0.42	0.79	0.44	0.51	0.54
Median	1.01	1.04	1.14	0.90	0.93	1.01	1.08
Repeat Visitsc
Mean	1.47	1.09	1.11	1.45	1.36	1.04	0.86
SD	0.89	0.22	0.19	1.22	0.72	0.29	0.18
Median	1.31	1.07	1.18	1.04	1.22	0.98	0.82

^aNumber indicates the order in which the terminals were visited. Visits 1–21 were part of the NCI-funded study. No ratios are provided for Elizabeth (22), Houston (34), and Portland (41) because of sampler failures.

^bRatios for all visits to terminals for which there were data.

^cRatios for 6 repeat visits to terminals for which there were data. Portland visit (41) contributed no data for ratios because the downwind samples failed.