Table 2.
Ambient environmental exposure levels in analyzed geographical areas (n = 28).
| Variable | March 13–17 | March 18–22 | March 23–27 | March 28–April 1 | April 2–6 |
|---|---|---|---|---|---|
| Mean temperature (°C) | 8.1 (6.8–8.8) | 13.6 (12.6–14.6) | 11.6 (10.6–12.5) | 10.3 (9.5–12.0) | 12.0 (11.4–13.0) |
| Mean daily minimum temperature (°C) | 3.4 (1.9–4.5) | 7.6 (5.7–9.3) | 6.8 (4.6–8.2) | 6.3 (5.6–9.2) | 7.0 (5.8–8.2) |
| Mean daily maximum temperature (°C) | 13.1 (11.8–13.9) | 19.3 (17.9–20.3) | 16.4 (15.6–17.6) | 13.9 (13.0–15.7) | 17.3 (16.1–18.1) |
| Precipitation (mm) | 3.4 (2.2–5.2) | 0.2 (0.0–1.0) | 2.0 (0.0–4.3) | 11.0 (9.0–16.2) | 0.0 (0.0–0.4) |
| Sunshine hours (h) | 6.4 (5.8–7.1) | 8.3 (7.6–9.4) | 7.5 (7.0–7.9) | 1.0 (0.4–2.3) | 9.2 (7.2–9.6) |
| Mean wind speed (m/s) | 3.0 (2.2–3.6) | 3.0 (2.3–3.9) | 3.0 (2.1–3.5) | 2.8 (2.1–3.7) | 3.4 (2.5–3.9) |
| Mean relative humidity (%) | 62.2 (58.3–64.2) | 55.4 (51.6–60.2) | 54.7 (50.7–60.5) | 79.2 (75.3–83.4) | 54.0 (50.8–57.9) |
| Mean daily minimum relative humidity (%) | 38.0 (35.2–42.7) | 33.1 (28.9–39.4) | 33.0 (28.8–38.4) | 65.9 (59.5–69.0) | 31.3 (29.2–35.0) |
| Mean absolute humidity (g/kg, DA) | 4.1 (3.9–4.3) | 5.3 (5.0–5.5) | 4.7 (4.3–5.3) | 6.4 (6.1–6.8) | 4.6 (4.3–4.9) |
| NO (ppb) | 2.1 (1.4–2.6) | 2.0 (1.1–3.0) | 2.8 (1.9–3.5) | 1.3 (1.0–1.7) | 1.3 (0.8–1.7) |
| NO2 (ppb) | 12.9 (8.7–14.3) | 14.3 (9.1–18.6) | 14.4 (12.9–17.4) | 10.2 (8.0–12.8) | 9.7 (7.2–11.0) |
| Ox (ppb) | 32.5 (30.1–34.6) | 36.9 (34.2–40.0) | 34.1 (32.8–35.5) | 30.7 (25.9–33.0) | 40.7 (38.5–42.2) |
| SPM (μg/m3) | 9.6 (8.9–10.7) | 15.2 (13.6–16.8) | 12.5 (11.2–15.6) | 10.1 (7.2–12.4) | 11.1 (9.7–12.5) |
| PM2.5 (μg/m3) | 7.8 (6.5–9.6) | 11.7 (10.5–13.9) | 10.6 (8.2–12.9) | 6.9 (6.0–7.9) | 9.8 (8.3–11.2) |
Values are expressed as median (interquartile rage). Abbreviations: DA, dry air; Ox, photochemical oxidant; NO, nitrogen monoxide; NO2, nitrogen dioxide; PM2.5, fine particulate matter; SPM, suspended particulate matter.