Table 2.

Model-estimated frequencies of pollutant concentrations exceeding acute health-based pollutant standards in homes that use natural gas cooking burners at least once per week (n = 6,634).

Pollutant in homes	Summer		Winter
	No hood	With hood	No hood	With hood
NO2 (k = 1.05/hr)
Exceedances of 1-hr NAAQS standard
Homes with exceedance (%)	41	10	55 ± 2a	18
Homes with exceedance due to indoor emissions only (%)	38	9	51 ± 1	15
Mean exceedances per home exceeding (n/week)b	3.0	2.5	3.4 ± 0.1	2.4
NO2 (k = 0.5/hr)
Exceedances of 1-hr NAAQS standard
Homes with exceedance (%)	51	17	70	30
Homes with exceedance due to indoor emissions only (%)	47	15	64	24
Mean exceedances per home exceeding (n/week)	3.3	2.6	3.6	2.7
CO
Exceedances 1-hr CAAQS standard
Homes with exceedance (%)	4	0.4	7 ± 1	2
Homes with exceedance due to indoor emissions only (%)	4	0.4	6 ± 1	1
Mean exceedances per home exceeding (n/week)	2.4	1.2	2.6 ± 0.5	2.4
Exceedances of 8-hr NAAQS standard
Homes with exceedance (%)	2	0.2	8 ± 1	2
Mean exceedances per home exceeding (n/week)	2.6	2.1	2.5 ± 0.3	1.9
HCHO
Exceedances of 1-hr OEHHA guideline
Homes with exceedance (%)	15	4	24 ± 2	11
Mean exceedances per home exceeding (n/week)	3.2	2.6	3.1 ± 0.3	2.6
Exceedances of 8-hr OEHHA guideline
Homes with exceedance (%)	27	12	52 ± 2	30
Mean exceedances per home exceeding (n/week)	3.3	2.6	3.5 ± 0.1	3.2
The two sets of NO2 data reflect the two first-order loss rates (ki) used to simulate NO2 dynamics. aSummary statistics for scenario 1 (only for ki = 1.05/hr for NO2) are presented as a mean ± range to indicate the variation across the 15 replicate runs that resulted from reassigning parameter values. The range is the difference between the mean value and the run with the largest difference, higher or lower, than the mean value. b"Mean exceedences per home exceeding" indicates the mean number of times a home that exceeded the specified standard at least once exceeded that standard during the simulated week.