Table 4.

Association between PM and hospitalizations for different model specifications, per increases of 10, 6.3, and 14.4 μg/m³ for PM_2.5, PM_2.5–10, and PM₁₀, respectively.

Pollutant/model	Cardiovascular admissions (lag 0–1)			Respiratory admissions (lag 0–5)
	Percent increase (95% CI)	χ2 p-value	I2	Percent increase (95% CI)	χ2 p-value	I2
aEstimated degrees of freedom per year were 3 (Milan, Turin, Emilia-Romagna, Bologna, Barcelona), 4(Rome), and 5(Marseille, Madrid) for cardiovascular hospitalization; and 3 (Turin, Bologna), 4(Marseille, Madrid), 5 (Rome), 6 (Milan, Emilia-Romagna), and 9 (Barcelona) for respiratory hospitalizations.
PM2.5
Base model	0.51 (0.12, 0.90)	0.20	29	1.36 (0.23, 2.49)	0.01	65
Trend, 8 df/year	0.28 (–0.12, 0.68)	0.11	41	0.87 (0.03, 1.72)	0.08	46
Trend, minimum PACFa	0.47 (0.14, 0.80)	0.23	25	1.64 (0.63, 2.65)	0.00	66
Temperature, lag 0–6 for warm period	0.52 (0.13, 0.91)	0.17	32	1.48 (0.29, 2.69)	0.00	69
PM2.5–10
Base model	0.46 (0.10, 0.82)	0.33	13	1.24 (–0.32, 2.82)	0.00	74
Trend, 8 df/year	0.34 (0.05, 0.63)	0.91	0	1.10 (0.01, 2.20)	0.05	55
Trend, minimum PACFa	0.53 (0.25, 0.81)	1.00	0	1.69 (0.26, 3.13)	0.00	72
Temperature, lag 0–6 for warm period	0.57 (0.26, 0.89)	0.50	0	1.40 (–0.27, 3.10)	0.00	76
PM10
Base model	0.53 (0.06, 1.00)	0.06	48	1.15 (0.21, 2.11)	0.04	52
Trend, 8 df/year	0.31 (–0.05, 0.67)	0.18	31	0.96 (0.31, 1.61)	0.26	22
Trend, minimum PACFa	0.56 (0.28, 0.84)	0.40	4	1.72 (0.85, 2.59)	0.03	55
Temperature, lag 0–6 for warm period	0.57 (0.12, 1.02)	0.07	47	1.29 (0.28, 2.32)	0.02	58