Table 1.

Ozone 12-hour treatment means^z, SUM0^y, SUM06^x, and the number of hours above 120 ppb.

	Treatment
	Subambient (CF)	Ambient (NF)	2.0X ambient (2.0X)
12-hour mean (ppb)	26.9 ± 7	41.7 ± 6	92.5 ± 15
SUM0 (ppm-h)	4.0 ± 2	5.6 ± 2	10.4 ± 3
SUM06 (ppm-h)	0	1.1 ± 1	8.1 ± 5
No. hr > 120 ppb	0	0	28.7+ 12

↵^z 12-hour (9:00 A.M. to 9:00 P.M.) ozone treatment means.
↵^y SUM0 24-hour sum of all hourly ozone concentrations.
↵^x SUM06 24-hour sum of all hourly ozone concentrations ⊕ 60 ppb.