Seasonal Variation of Airborne Particle Deposition Efficiency in the Human Respiratory System

Figures & data

TABLE 1 Average concentration, MMAD, and GSD of measured species during the Fresno summer and winter sampling events. Note that trace element concentrations are shown in ng m⁻³ while OC, EC, and water-soluble ions are shown in μg m⁻³

	Fresno summer				Fresno winter
	Average concentration	Standard deviation	MMAD (μm)	GSD (μm)	Average concentration	Standard deviation	MMAD (μm)	GSD (μm)
Trace species (ng m^−3)
Na	76.7	54.6	0.84	6.34	57.2	58.9	0.59	3.29
Mg	12.3	7.96	1.52	2.49	3.49	2.41	0.80	3.12
Al	48.2	70.3	0.31	2.00	34.7	31.1	0.73	3.82
P	10.7	12.7	0.42	2.09	63.5	76.6	0.45	3.52
S	782	592	0.35	2.08	512	361	0.54	2.46
K	8.02	7.02	0.65	1.75	18.2	8.77	0.45	2.24
Ca	9.01	12.1	0.70	8.57	8.22	3.39	0.47	3.91
Ti	1.26	0.69	1.27	2.61	2.51	2.32	1.43	3.10
V	0.12	0.07	0.47	1.58	0.04	0.03	0.56	2.54
Mn	1.01	0.65	0.94	2.39	0.91	0.71	0.69	1.23
Fe	30.8	28.3	1.18	3.27	29.1	22.1	1.99	3.70
Ni	11.7	18.8	2.71	3.01	4.92	3.19	0.33	4.85
Cu	1.00	1.04	0.80	3.62	1.85	0.97	1.16	4.09
Zn	8.97	8.27	0.55	4.23	31.6	36.3	0.46	2.57
As	0.13	0.12	0.34	1.71	0.25	0.14	0.34	1.84
Se	0.19	0.19	0.85	1.80	0.10	0.01	0.54	1.19
Br	4.72	2.42	0.31	1.80	7.31	6.29	0.45	1.81
Sn	1.16	1.31	0.30	1.67	3.20	2.90	0.51	2.70
Sb	0.56	0.57	0.53	2.21	2.43	1.72	0.67	2.13
Ba	2.59	2.25	1.02	2.54	1.53	0.93	1.55	2.88
Pb	0.25	0.15	0.32	1.56	0.76	0.28	0.34	2.59
Major species (μg m^−3)
OC	3.86	1.95	0.31	1.70	4.66	0.97	0.30	1.97
EC	0.54	0.29	0.23	1.80	0.79	0.40	0.26	1.71
Cl^−	0.08	0.08	0.50	2.16	0.05	0.01	0.45	2.85
NO3	0.75	0.64	0.58	2.21	10.8	7.81	0.54	1.60
SO4	1.66	0.60	0.33	1.58	1.19	0.50	0.50	1.82
Na^+	0.11	0.08	0.76	2.93	0.06	0.03	0.64	3.06
NH4 ^+	0.68	0.25	0.33	1.78	3.19	2.01	0.51	1.56
K^+	0.03	0.05	0.46	2.46	0.05	0.04	0.40	1.59
Ca2 ^+	0.02	0.01	0.42	2.02	0.01	0.01	0.59	2.33

FIG. 1 Relative MOUDI size distributions of individual species. Concentrations are normalized to maximum observed PM_1.8 concentrations (values in the parenthesis). Dashed lines represent summer while solid lines represent winter.

FIG. 2 Average MOUDI nitrate size distribution and respiratory deposition fractions during the Fresno summer and winter sampling events.

FIG. 3 (a–c) Nitrate deposition versus PM_1.8 specific nitrate concentrations and (d–f) PM_1.8 total mass concentrations during the Fresno summer and winter sampling events. Plots a, b, and c show specific deposition efficiencies while plots d, e, and f show total deposition efficiencies.

FIG. 4 Average total deposition efficiency in all regions of the respiratory tract comparing component deposition and PM_1.8 total mass concentrations using least squares method. Units are μg of each component deposited per μg PM_1.8 total mass inhaled. Error bars represent 95% CI.

FIG. 5 Specific deposition efficiencies comparing component deposition and PM_1.8 component mass concentrations using least squares method. Units are represented as μg of each component deposited per μg PM_1.8 component mass inhaled. Error bars represent 95% CI.