Pedestrian Exposure to Size-Resolved Particles in Milan

Figures & data

Table 1. Size-resolved conversion factors ρ _i (g cm^{− 3}) used in eq. 1.

Size Bin (μm)	ρ i (g cm^−3)
0.3–0.5	2.37
0.5–0.7	2.75
0.7–1.0	3.22
1.0–2.0	3.17
2.0–3.0	2.58
3.0–5.0	2.40
5.0–10	2.16

Figure 1. Route map (MS: air quality monitoring stations; M: meteorological station; the arrow indicates the route start and finish point).

Table 2. Pedestrian route sector descriptions

Sector ID	Sector Features	Sector Description
UC	University campus area	2 lanes, single-carriageway road + streetcar tracks bordering the university campus
S1	High-traffic road	2 lanes, double-carriageway road + 2 lanes reserved for public transportation vehicles
S2	High-traffic road	2 lanes, double-carriageway road with traffic lights causing queued idling vehicles
G1	Green area	Park, unpaved walkways
S3	Low-emission zone	2 lanes, double-carriageway road narrowing into a 2-lane, single carriageway road
P1	Pedestrian zone	Narrow street in commercial area
S4	Low-emission zone	2 lanes, single-carriageway stone-paved road with streetcar tracks
PG	Pedestrian gallery	Covered passage connecting city center squares
P2	Pedestrian zone	Main city center square
S5	Low-emission zone	2 lanes, single-carriageway road
G2	Green area	Main city center park, unpaved walkways
S6	Low-emission zone	2 lanes, single-carriageway road
SW	Subway	Public transportation underground railway
S7	Side street	2 lanes, single-carriageway road with low-intensity traffic

Table 3. Air quality and meteorological conditions on measurement days

Date	Time of the Day	PM2.5* (μg m^−3)	PM10* (μg m^−3)	Wind Speed (m s^−1)	Wind Direction	Rainfall** (mm)
30 April	M	19	38	0.76	SW	0 (0)
	A			0.83	SW
03 May	M	6	12	0.50	N	27.6 (8.4)
	A			0.60	N
05 May	M	9	15	0.27	NNE	25.7 (3.1)
	A			0.73	E
07 May	M	10	18	0.40	NE	0.3 (0.2)
	A			0.50	ESE
09 May	M	10	16	0.5	SSE	3.1 (2.2)
	A			1.1	SE
12 May	M	10	18	0.97	N	4.3 (1.4)
	A			1.05	N
14 May	M	13	18	0.85	NW	5.3 (1.2)
	A			0.93	NW
19 May	M	16	36	0.90	SE	0 (0)
	A			1.50	SSE
24 May	M	15	28	0.53	ESE	0 (0)
	A			1.18	ENE
26 May	M	13	28	1.30	SW	0 (0)
	A			1.13	SSE
28 May	M	21	35	0.47	ENE	0 (0)
	A			0.50	NE
Note: Data from the regional air quality and meteorological monitoring networks for Milan urban area. M = morning; A = afternoon.
*Daily average concentration from the three urban monitoring sites: MS1, MS2, MS3.
**Cumulative daily rainfall and maximum hourly precipitation rate (in parentheses).

Figure 2. Time pattern of PM₁₀ (solid line), PM_2.5 (dashed line), and PM₁ (thick line) concentration (μg m⁻³) measured during the afternoon route on May 19, 2010.

Figure 3. Sector-resolved box-plots for the distributions of 1-min PM₁₀ concentrations (μg m⁻³) measured during the morning and afternoon routes.

Figure 4. Sector-resolved box-plots for the distributions of 1-min PM_2.5 concentrations (μg m⁻³) measured during the morning and afternoon routes.

Figure 5. Sector-resolved box-plots for the distributions of 1-min PM₁ concentrations (μg m⁻³) measured during the morning and afternoon routes.

Figure 6. Sector averaged mass distribution (thin lines, white symbols: morning route; thick lines, black symbols: afternoon route) for sectors G2, S2, and SW.

Figure 7. Size-resolved box-plots for the distributions of the route-averaged exposures (μg m⁻³) measured during the morning and afternoon routes. (Diamonds: the Sunday's afternoon route.)

Figure 8. Representation of the sectors on the factorial plane in the morning (upper panel) and in the afternoon (lower panel). Variable considered: particle number size distribution. (Circled data points represent SW sector; grey symbols represent the rainy days.)

Figure 9. Comparison between the estimated and measured average exposures for the morning (black symbols) and afternoon (white symbols) routes.