Table 1.

Summary statistics of ozone monitors and concentrations, Medicare enrollees, and cause-specific deaths among Medicare enrollees

Characteristics	ICD−9 code	25th Median 75th%a	Total number	Total %
Monitoring stations			1151
O3b(ppb)		50 55 60
Medicare enrollees		385811,697 28,311	22,159,190
All-cause deaths		724 2,471 6458	5,766,091
Non-accidental	A−R	704 2,412 6293	5,637,693	97.8
Accidental	V−Y	21 62 155	128,372	2.2
All cardiovascular	I00−I99	279 956 2537	2,333,681	40.5
IHD	I20−I25	136 461 1226	1,245,401	21.6
CBV	I60−I69	55 183 477	410,187	7.1
CHF	I50	21 73 183	158,649	2.8
All respiratory	J00−J99	85 281 725	633,216	11.0
COPD	J40−J44	73 155 380	328,957	5.7
Pneumonia	J12−J18	20 67 177	174,932	3.0
All cancer	C−D	156 534 1437	1,277,716	22.2
Lung cancer	C34	46 155 403	350,357	6.1

Time period: 2000–2008, USA

ICD-9 the 9th revision of the International Classification of Disease, O₃ ozone, IHD ischemic heart disease, CBV cerebrovascular disease, CHF congestive heart failure, COPD chronic obstructive pulmonary disease

Medicare enrollees ages 65–120

^aValues are medians among locations and months, with 25th and 75th percentile given in subscripts

^bWarm-season average of daily 1-h maximum ozone concentrations