Table 2.

Spatio-temporal distribution of cardiovascular ED visits and air pollutants

	Mean ± SD	Min.	1st Q.	Median	3rd Q.	Max.
ED visits
Daily counts per zip	0.09 ± 0.31	0.00	0.00	0.00	0.00	3.00
Total counts per zip	31.69 ± 32.39	0.00	7.75	22.50	45.75	153.00
Total counts per day	7.29 ± 2.75	0.00	5.00	7.00	9.00	16.00
Air pollutants
NO${}_2$ (ppmv)	6.26 ± 4.31	0.38	2.87	5.15	8.59	24.29
PM2.5 ($\mathrm{\mu }\text{g}/{\text{m}}^3$)	9.48 ± 4.76	1.13	5.88	8.60	12.00	29.22
Ozone (ppb)	39.63 ± 10.81	13.77	31.87	38.65	45.44	87.21