Table 4.

Summary of the intervention conditions used in the mass balance model.

Parameter	Units	Values	Description
λ V	1/h	0.71*	Estimated annual infiltration rate. Calculated from blower door ACH50 value
λ D	1/h	0.39 [18]	Rate of particle removal by deposition on surfaces
P	-	0.82 [50]	Particle penetration factor
Q/V	1/h	4.96**	Recirculation air flow rate of the HVAC normalized by volume
D	-	0.28 average *	Duty cycle. Experiment time series calculation discussed in Section 4.1
ε H	-	0.30	HVAC filter efficiency for PM2.5. Determined from MERV rating using published methods [48,49]
λ PAC	1/h	0.87**	PAC filter efficiency for PM2.5 multiplied by the air flow rate of the portable air cleaner normalized by volume. Determined from manufacturer CADR specifications for portable air cleaner
V	m3	456*	Volume of the house
Co	μg/m3	Experiment time series measurement as shown in Section 4.1.	Outside particle concentration

^*Measured from test home;

^**manufacture- reported equipment; specifications.