Table 2.

Cross-correlation values between the daily incidence of infection and the PM2.5 concentration obtained varying the lag between the two series.

Lag (Days)	8	9	10	11	12	13	14
Bergamo	−0.13	0.20	0.45	0.26	0.20	−0.14	−0.40
Brescia	−0.02	0.07	0.28	0.34	0.26	−0.15	−0.43
Como	−0.24	0.25	0.60	0.11	0.01	−0.13	−0.35
Cremona	−0.09	0.08	0.28	0.29	0.28	−0.12	−0.40
Lecco	−0.25	0.21	0.56	0.25	0.03	−0.14	−0.38
Lodi	−0.09	0.12	0.28	0.17	0.20	−0.13	−0.40
Mantova	0.00	0.03	0.31	0.39	0.30	−0.15	−0.38
Milano	−0.17	0.20	0.49	0.15	−0.04	−0.22	−0.41
Monza	−0.20	0.23	0.59	0.24	−0.04	−0.19	−0.37
Pavia	−0.07	0.27	0.27	0.03	−0.03	−0.21	−0.31
Sondrio	−0.31	−0.05	0.27	0.09	0.28	0.02	−0.21
Varese	−0.30	0.20	0.57	0.13	0.08	−0.15	−0.37