Quantification of online removal of refractory black carbon using laser-induced incandescence in the single particle soot photometer

Figures & data

Figure 1. Experimental configuration.

Figure 2. Mass-weighted size distributions of Aquadag before (solid black) and after (dashed) undergoing LII. Initial size distributions for DMA-selected mobility diameters of (a) 100 nm, (b) 150 nm, (c) 300 nm, (d) 350 nm, (e) 500 nm, and (f) polydisperse samples as detected by incandescence in the SP2. Plotted diameter is d_m with residuals (ρ_eff = 1, d_me = d_m for spherical particles). Gaussian fits (gray [blue]) are used to determine the reported Sigma (σ) values.

Table 1. Removal rates for Aquadag exposed to LII by mass concentration, number concentration, percent scattering, and absorption. Both the mobility-selected particle d_m range as determined by ±2σ from the Gaussian fits to the original size distributions and the total particles measured by the SP2 are reported for the mass and number concentrations. Reported averages are from the mobility-selected samples, and uncertainties are the standard deviations.

Incandescent	Gaussian-fit		Total		Scattering (%)		Absorption (%)
dm (nm)	Mass (%)	Number (%)	Mass (%)	Number fraction	405 nm	532 nm	405 nm	532 nm	781 nm
100 nm	56.3 ± 5.08	49.0 ± 8.35	84.5 ± 0.81	0.55 ± 0.04	88.6	—	—	90.5	55.6
150 nm	90.0 ± 0.97	88.7 ± 1.82	91.6 ± 0.31	0.80 ± 0.04	97.6	—	76.1	91.3	85.5
300 nm	99.5 ± 0.07	99.4 ± 0.10	91.8 ± 0.38	1.48 ± 0.09	97.6	99.2	25.4	49.3	74.5
350 nm	98.8 ± 0.03	99.9 ± 0.03	89.9 ± 0.57	1.86 ± 0.12	74.3	—	8.1	38.8	55.7
500 nm	99.9 ± 0.02	99.6 ± 0.07	92.1 ± 0.53	3.30 ± 0.23	96.9	99.3	9.2	39.2	65.3
Average	88.9 ± 18.6	87.3 ± 21.9	90.5 ± 3.15	1.45 ± 1.03	91 ± 10	99 ± 0.01	30 ± 32	62 ± 27	67 ± 13
Polydisperse	N/A	N/A	93.3 ± 0.20	0.76 ± 0.03	93.5	97.0	91.7	91.5	94.6

Figure 4. (a) Mass and (b) number size distributions of the incandescent particles remaining after LII normalized by the original Aquadag mass and number concentrations, respectively.

Figure 3. Number size distributions of Aquadag before (solid black) and after (dashed) undergoing LII. Initial size distributions for DMA-selected mobility diameters of (a) 100 nm, (b) 150 nm, (c) 300 nm, (d) 350 nm, (e) 500 nm, and (f) polydisperse samples as detected by incandescence in the SP2. Plotted diameter is d_m with residuals (ρ = 1, d_me = d_m for spherical particles). Gaussian fits (gray [blue]) are used to determine the reported Sigma (σ) values.

Figure 5. (a) Mass weighted mean d_me and (b) individual particle mass remaining after LII versus the original Aquadag mean d_m selected with the DMA, and (c) mass mean d_me after LII versus the total mass concentration of the original sample.