| Pollutant | IQR† | One-pollutant model‡ | Multi-pollutant models | |
| Four size modes | PM10+a212 | |||
| CVD hospital admissions (age ⩾65 years)§ | ||||
| n = 676 | n = 564 | |||
| PM10 | 13 | 1.03 (1.01 to 1.05)** | 1.05 (1.01 to 1.09)** | |
| NC100 | 3259 | 1.00 (0.98 to 1.02) | ||
| NC¶a12 | 342 | 0.99 (0.97 to 1.01) | 0.99 (0.97 to 1.02) | |
| NCa23 | 1786 | 0.99 (0.96 to 1.01) | 0.99 (0.96 to 1.02) | |
| NCa57 | 3026 | 1.01 (0.98 to 1.02) | 0.99 (0.97 to 1.02) | |
| NCa212 | 495 | 1.02 (1.00 to 1.04)** | 1.02 (1.00 to 1.05)** | 0.98 (0.95 to 1.01) |
| RD hospital admissions (age ⩾65 years)†† | ||||
| n = 701 | n = 564 | |||
| PM10 | 13 | 1.05 (1.02 to 1.09)** | 1.04 (0.98 to 1.11) | |
| NC100 | 3259 | 1.03 (0.99 to 1.07) | ||
| NCa12 | 342 | 1.01 (0.98 to 1.05) | 1.01 (0.97 to 1.05) | |
| NCa23 | 1786 | 0.99 (0.94 to 1.03) | 0.98 (0.94 to 1.03) | |
| NCa57 | 3026 | 1.04 (1.00 to 1.08)** | 1.02 (0.97 to 1.06) | |
| NCa212 | 495 | 1.04 (1.01 to 1.08)** | 1.03 (0.99 to 1.07) | 1.01 (0.96 to 1.07) |
| Asthma hospital admissions (age 5–18 years)‡‡ | ||||
| n = 722 | n = 559 | |||
| PM10 | 13 | 1.02 (0.93 to 1.12) | 0.94 (0.81 to 1.09) | |
| NC100 | 3259 | 1.06 (0.97 to 1.16) | ||
| NCa12 | 342 | 1.08 (0.99 to 1.18) | 1.07 (0.97 to 1.19) | |
| NCa23 | 1786 | 1.09 (0.98 to 1.21) | 1.08 (0.97 to 1.21) | |
| NCa57 | 3026 | 1.02 (0.94 to 1.12) | 0.93 (0.83 to 1.04) | |
| NCa212 | 495 | 1.08 (1.00 to 1.17)** | 1.12 (1.02 to 1.23)** | 1.10 (0.96 to 1.13) |
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*Relative risks (RR) and 95% confidence intervals per IQR adjusted for temperature, dew point, season, day of the week, influenza, public holidays for all three outcomes, and grass pollen and school holidays for asthma.
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†IQR, interquartile range, difference between 75th and 25th percentile.
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‡Sample size (n) for pollutants in the one-pollutant model is limited to days when NCtot is available.
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§RR for 4-day average, mean (lag 0–3).
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¶NC, number concentration of particles; a12, size mode with median diameter of 12 nm; a23, size mode with median diameter of 23 nm; a57, size mode with median diameter of 57 nm; a212, size mode with median diameter of 212 nm.
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**p<0.05.
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††RR for 5-day average, mean (lag 0–4).
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‡‡RR for 6-day average, mean (lag 0–5).
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CVD, cardiovascular disease; RD, respiratory disease.
