Chemical Mass Closure and Chemical Characteristics of Ambient Ultrafine Particles and other PM Fractions

Figures & data

FIG. 1 Schematic diagram of the (a) Syuefu road and (b) Syueshan highway tunnel.

FIG. 2 Schematic diagram of the configurations of the samplers.

TABLE 1 Comparison of PM concentration (μg/m³) between MOUDI (M) and Dichot (D) at the roadside and in the tunnel

	PM10		PM2.5
					PM0.1
Site	M1	D1	M1	D1	M1
Roadside	54.3 ± 23.6	62.1 ± 27.9	27.5 ± 12.5	30.4 ± 14.7	2.2 ± 0.6
T* daytime**	87.9 ± 9.9	92.8 ± 11.4	78.0 ± 11.2	73.3 ± 10.0	33.2 ± 6.5
T midnight***	54.3 ± 3.8	55.2 ± 4.4	45.7 ± 3.1	47.2 ± 4.5	9.1 ± 1.7
T rush hour****	158 ± 20	177 ± 18	132 ± 16	148 ± 20	46.5 ± 5.2
*: tunnel; **: during 9 AM–9 PM (mean of ten 3-h measurements); ***: 0–6 AM (mean of three 6-h measurements); ****: holiday 8 AM–11 AM (mean of three 3-h measurements).

FIG. 3 Comparison of particle mass distributions at the roadside and tunnel. Error bars represent one standard deviation.

FIG. 4 Average chemical compositions (%) of PMs at Syuefu roadside and in the Syueshan highway tunnel. One standard deviation of each data point ranges from 1.6 to 9.7% depending on the PM fractions and chemical compositions.

FIG. 5 Comparison of water-soluble ion concentrations (μg/m³) in all PM fractions between the tunnel and roadside.

FIG. 6 Concentrations of elements in all PM fractions at the roadside (a) and in the tunnel (b). Error bars represent one standard deviation.

FIG. 7 Ratio of the concentration of the elements in the tunnel to that at the roadside (T/R).