Table 3.

The variable importance of pollutants on hospital visits using the random forest (RF) model.

		PM10	PM2.5	O3	NO2	CO	SO2
Outpatient Hospital Visits	4-day lag	1.939	1.839	3.820	6.478	4.454	2.594
	3-day lag	1.647	2.195	2.767	5.616	6.230	2.014
	2-day lag	1.981	2.302	2.333	7.339	4.518	2.250
	1-day lag	1.711	2.041	2.361	3.682	2.531	2.229
	0-day lag	2.251	2.180	3.151	7.160	3.412	4.284
Hospital Admissions	4-day lag	2.274	2.249	2.467	2.279	5.252	1.967
	3-day lag	1.940	2.085	1.984	2.083	3.883	1.915
	2-day lag	2.003	2.931	2.002	2.010	3.082	1.742
	1-day lag	1.719	2.176	2.214	2.705	2.023	2.035
	0-day lag	2.386	2.944	1.952	2.365	2.408	2.217
Emergency Department Visits	4-day lag	2.199	1.461	2.017	2.188	3.164	1.710
	3-day lag	1.925	1.552	1.745	2.088	4.410	1.624
	2-day lag	2.192	1.466	1.742	2.144	3.607	1.714
	1-day lag	1.577	1.319	1.786	1.753	1.972	1.928
	0-day lag	2.275	1.441	1.710	2.577	2.526	2.555