Modeling Critical Air Exchange Rates (CAERs) for aerosol number concentrations from nano-particle sources using an “effective coagulation coefficient” approach

Figures & data

Figure 1. Total number concentration vs. ventilation rate for (a) high and (b) medium source emission rates—comparison of models.

Figure 2. Effect of Hamaker–van der Waals and viscous forces on the steady-state number concentration—numerical model results.

Figure 3. Effective coagulation coefficient vs. for an initial particle diameter (d_u0 = 10 nm) at the source.

Table 1. Parameters to estimate K_eff (Equation (17[17] )) for various D_f.

Df	A1	A2	B	C
2	18.638	226.242	8.026	0.555
2.5	18.914	70.389	2.228	0.616
3	19.255	36.540	1.719	0.657

Figure 4. Steady-state number concentration ratio (N₀(λ)/N₀(λ = 0)) vs. ventilation rate for different fractal dimensions (D_f) and source strengths (S). N₀(λ = 0) is different for each of the emission scenario.

Figure 5. Steady-state number concentration vs. ventilation rate for fractal dimensions (2, 2.5, 3); S = 10¹² m⁻³ s⁻¹.

Table 2. CAER values for different S and D_f.

	CAER (h^−1)
	Df – 2	Df – 2.5	Df – 3
Low S (10^8 m^−3 s^−1)	—	—	—
Medium S (10^10 m^−3 s^−1)	3.5	2.4	1.6
High S (10^12 m^−3 s^−1)	39	30	24