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Table 2 Frequency at which each Day-Type (n = 64) occurred by city, as well as the terminal node designation from the city-specific trees

From: Associations between ambient air pollutant mixtures and pediatric asthma emergency department visits in three cities: a classification and regression tree approach

Day- Typea

Atlanta

Dallas

St. Louis

N

%

Terminal Nodeb

N

%

Terminal Nodec

N

%

Terminal Noded

1/1/1

606

(15.1 %)

Referent

121

(9.1 %)

Referent

115

(4.9 %)

Referent

1/1/2

137

(3.4 %)

1A

29

(2.2 %)

1D

30

(1.3 %)

6S

1/1/3

98

(2.4 %)

1A

30

(2.2 %)

1D

25

(1.1 %)

6S

1/1/4

24

(0.6 %)

1A

6

(0.4 %)

1D

11

(0.5 %)

1S

1/2/1

137

(3.4 %)

5A

46

(3.4 %)

1D

152

(6.5 %)

3S

1/2/2

56

(1.4 %)

5A

9

(0.7 %)

1D

46

(2 %)

7S

1/2/3

70

(1.7 %)

5A

4

(0.3 %)

1D

63

(2.7 %)

7S

1/2/4

21

(0.5 %)

5A

1

(0.1 %)

1D

26

(1.1 %)

1S

1/3/1

61

(1.5 %)

5A

70

(5.2 %)

1D

171

(7.3 %)

2S

1/3/2

46

(1.1 %)

5A

9

(0.7 %)

1D

47

(2 %)

2S

1/3/3

70

(1.7 %)

5A

5

(0.4 %)

1D

86

(3.7 %)

2S

1/3/4

33

(0.8 %)

5A

0

(0 %)

1D

43

(1.8 %)

2S

1/4/1

11

(0.3 %)

4A

114

(8.5 %)

1D

84

(3.6 %)

2S

1/4/2

23

(0.6 %)

4A

18

(1.3 %)

1D

63

(2.7 %)

2S

1/4/3

41

(1 %)

4A

0

(0 %)

1D

99

(4.2 %)

2S

1/4/4

28

(0.7 %)

4A

0

(0 %)

1D

101

(4.3 %)

2S

2/1/1

221

(5.5 %)

1A

116

(8.7 %)

1D

30

(1.3 %)

3S

2/1/2

92

(2.3 %)

1A

34

(2.5 %)

1D

13

(0.6 %)

6S

2/1/3

104

(2.6 %)

1A

41

(3.1 %)

1D

19

(0.8 %)

6S

2/1/4

25

(0.6 %)

1A

19

(1.4 %)

1D

14

(0.6 %)

1S

2/2/1

80

(2 %)

6A

16

(1.2 %)

1D

47

(2 %)

3S

2/2/2

32

(0.8 %)

6A

10

(0.7 %)

1D

12

(0.5 %)

7S

2/2/3

31

(0.8 %)

6A

5

(0.4 %)

1D

17

(0.7 %)

7S

2/2/4

10

(0.2 %)

6A

1

(0.1 %)

1D

4

(0.2 %)

1S

2/3/1

42

(1 %)

7A

28

(2.1 %)

1D

69

(2.9 %)

2S

2/3/2

21

(0.5 %)

7A

7

(0.5 %)

1D

18

(0.8 %)

2S

2/3/3

31

(0.8 %)

7A

2

(0.1 %)

1D

19

(0.8 %)

2S

2/3/4

16

(0.4 %)

7A

0

(0 %)

1D

3

(0.1 %)

2S

2/4/1

7

(0.2 %)

4A

54

(4 %)

1D

58

(2.5 %)

2S

2/4/2

11

(0.3 %)

4A

6

(0.4 %)

1D

31

(1.3 %)

2S

2/4/3

26

(0.6 %)

4A

0

(0 %)

1D

33

(1.4 %)

2S

2/4/4

26

(0.6 %)

4A

1

(0.1 %)

1D

17

(0.7 %)

2S

3/1/1

123

(3.1 %)

2A

59

(4.4 %)

5D

11

(0.5 %)

3S

3/1/2

88

(2.2 %)

2A

34

(2.5 %)

2D

10

(0.4 %)

6S

3/1/3

154

(3.8 %)

2A

30

(2.2 %)

2D

17

(0.7 %)

6S

3/1/4

80

(2 %)

2A

12

(0.9 %)

2D

12

(0.5 %)

1S

3/2/1

33

(0.8 %)

2A

17

(1.3 %)

5D

24

(1 %)

3S

3/2/2

23

(0.6 %)

2A

11

(0.8 %)

2D

12

(0.5 %)

7S

3/2/3

45

(1.1 %)

2A

16

(1.2 %)

2D

24

(1 %)

7S

3/2/4

39

(1 %)

2A

4

(0.3 %)

2D

14

(0.6 %)

1S

3/3/1

21

(0.5 %)

2A

28

(2.1 %)

6D

31

(1.3 %)

2S

3/3/2

26

(0.6 %)

2A

11

(0.8 %)

2D

18

(0.8 %)

2S

3/3/3

37

(0.9 %)

2A

7

(0.5 %)

2D

23

(1 %)

2S

3/3/4

26

(0.6 %)

2A

1

(0.1 %)

2D

14

(0.6 %)

2S

3/4/1

4

(0.1 %)

2A

35

(2.6 %)

6D

44

(1.9 %)

2S

3/4/2

9

(0.2 %)

2A

7

(0.5 %)

2D

43

(1.8 %)

2S

3/4/3

23

(0.6 %)

2A

6

(0.4 %)

2D

45

(1.9 %)

2S

3/4/4

42

(1 %)

2A

4

(0.3 %)

2D

14

(0.6 %)

2S

4/1/1

22

(0.5 %)

3A

15

(1.1 %)

3D

0

(0 %)

3S

4/1/2

38

(0.9 %)

3A

17

(1.3 %)

3D

7

(0.3 %)

6S

4/1/3

111

(2.8 %)

3A

25

(1.9 %)

3D

7

(0.3 %)

6S

4/1/4

216

(5.4 %)

3A

11

(0.8 %)

3D

19

(0.8 %)

1S

4/2/1

11

(0.3 %)

3A

14

(1 %)

4D

8

(0.3 %)

3S

4/2/2

17

(0.4 %)

3A

10

(0.7 %)

4D

5

(0.2 %)

7S

4/2/3

60

(1.5 %)

3A

26

(1.9 %)

4D

10

(0.4 %)

7S

4/2/4

164

(4.1 %)

3A

5

(0.4 %)

4D

27

(1.1 %)

1S

4/3/1

7

(0.2 %)

3A

15

(1.1 %)

4D

6

(0.3 %)

4S

4/3/2

19

(0.5 %)

3A

15

(1.1 %)

4D

11

(0.5 %)

4S

4/3/3

43

(1.1 %)

3A

24

(1.8 %)

4D

38

(1.6 %)

4S

4/3/4

138

(3.4 %)

3A

18

(1.3 %)

4D

58

(2.5 %)

4S

4/4/1

1

(0 %)

3A

17

(1.3 %)

4D

8

(0.3 %)

5S

4/4/2

1

(0 %)

3A

8

(0.6 %)

4D

28

(1.2 %)

5S

4/4/3

38

(0.9 %)

3A

13

(1 %)

4D

68

(2.9 %)

5S

4/4/4

116

(2.9 %)

3A

20

(1.5 %)

4D

132

(5.6 %)

5S

  1. aDay-Types are represented by the level of O3, NO2 and PM2.5 respectively
  2. bThe seven terminal nodes from the Atlanta tree are designated as 1A – 7A
  3. cThe six terminal nodes from the Dallas tree are designated as 1D – 6D
  4. dThe seven terminal nodes from the St. Louis tree are designated as 1S – 7S