Table 23.

Summary Statistics for VOC and PM Measurements in Yard Upwind Locations

Location / Compound	First Visit			Second Visit			Significant Differencea and Direction
	Observations (n)	GM (µg/m3)	GSD (µg/m3)	Observations (n)	GM (µg/m3)	GSD (µg/m3)
Philadelphia
EC	24	0.5	1.9	38	0.8	2.1
PM2.5	24	10.7	1.5	38	13.9	1.8	+a
Benzene	26	1.3	1.5	36	0.9	1.5	−a
Toluene	26	2.0	1.6	36	2.2	2.3
Ethylbenzene	26	0.3	1.6	36	0.2	2.1
m&p-Xylenes	26	1.1	1.6	36	0.8	2.2	−a
o-Xylene	26	0.4	1.6	36	0.3	2.1
Formaldehyde	29	2.0	5.0	34	3.3	1.6
Columbus
EC	20	0.6	1.7	24	1.1	2.3	+a
PM2.5	22	9.1	2.2	23	12.5	1.6
Benzene	13	0.9	3.5	22	1.0	2.3
Toluene	13	2.6	6.0	22	2.4	4.3
Ethylbenzene	13	0.5	5.9	22	0.4	3.9
m&p-Xylenes	13	1.5	6.4	22	1.1	4.3
o-Xylene	13	0.6	6.6	22	0.4	4.3
Formaldehyde	12	0.9	11.3	20	3.1	1.5
Milwaukee
EC	29	0.1	3.4	31	0.2	5.6	+a
PM2.5	27	3.0	2.5	32	8.5	1.7	+a
Benzene	28	0.6	1.9	28	0.6	1.5
Toluene	28	0.8	3.0	28	1.5	1.9	+a
Ethylbenzene	28	0.1	5.6	28	0.2	1.9	+a
m&p-Xylenes	28	0.4	4.8	28	0.7	2.0
o-Xylene	28	0.1	5.1	28	0.2	1.9
Formaldehyde	20	3.0	1.9	21	1.9	4.0
Phoenix
EC	6	0.8	2.1	36	1.2	1.7
PM2.5	3	15.3	1.4	36	16.5	1.4
Benzene	6	0.9	1.5	30	0.9	1.7
Toluene	6	3.7	1.5	30	4.0	1.7
Ethylbenzene	6	0.6	1.5	30	0.6	2.0
m&p-Xylenes	6	2.3	1.5	30	1.8	2.1
o-Xylene	6	0.3	13.7	30	0.7	2.0
Formaldehyde	6	7.9	1.4	32	3.1	2.8	−a
Portland
EC	18	0.4	1.4	36	0.4	2.3
PM2.5	17	4.2	1.4	35	5.8	1.6	+a
Benzene	17	1.0	2.0	30	0.6	1.8	−a
Toluene	17	2.4	1.7	30	1.8	2.1
Ethylbenzene	17	0.4	1.7	30	0.3	2.0
m&p-Xylenes	17	1.2	1.6	30	0.9	2.2
o-Xylene	17	0.3	4.3	30	0.3	2.1
Formaldehyde	15	2.5	3.5	25	3.7	1.8
Denver
EC	32	0.6	1.8	32	0.7	2.0
PM2.5	32	7.1	1.5	29	7.4	2.2
Benzene	30	1.6	1.5	28	1.5	1.4
Toluene	30	3.7	1.7	28	4.0	1.4
Ethylbenzene	30	0.7	1.8	28	0.5	1.7	−a
m&p-Xylenes	30	1.9	1.8	28	1.5	1.8
o-Xylene	30	0.6	1.9	28	0.5	1.7
Formaldehyde	32	3.4	1.3	30	2.9	1.3	−a

^aSignificant differences (P < 0.05) in median values using Wilcoxon rank sum non-parametric comparison test. + indicates increase in GM; − indicates decrease in GM.