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Table 5 Adjusted odds ratios* for emergency department visits for asthma among patients 5 – 14 years of age, by season

From: Outdoor air pollution and emergency department visits for asthma among children and adults: A case-crossover study in northern Alberta, Canada

Pollutant

Mean

IQR

All seasons

Season

     

October to March

April to September

   

OR

95% C.I.

OR

95% C.I.

OR

95% C.I.

SO2

Same day

3.0

0.96

0.93–1.00

0.98

0.93–1.03

0.94

0.89–0.99

 

1-day lag

 

0.98

0.94–1.02

0.98

0.93–1.03

0.97

0.93–1.03

 

3-day average

 

0.94

0.90–1.00

0.96

0.89–1.03

0.92

0.85–1.00

 

5-day average

 

0.97

0.91–1.03

1.01

0.93–1.10

0.91

0.83–1.00

NO2

Same day

13.5

0.99

0.95–1.03

0.98

0.93–1.03

1.00

0.94–1.06

 

1-day lag

 

1.05

1.01–1.09

1.04

0.99–1.09

1.08

1.01–1.15

 

3-day average

 

1.05

1.00–1.10

1.03

0.97–1.10

1.08

0.99–1.17

 

5-day average

 

1.09

1.03–1.15

1.07

1.00–1.15

1.13

1.02–1.24

CO

Same day

0.5

0.98

0.96–1.01

0.97

0.94–1.00

1.02

0.95–1.08

 

1-day lag

 

1.03

1.00–1.05

1.02

0.99–1.05

1.06

1.00–1.14

 

3-day average

 

1.02

0.98–1.05

1.01

0.97–1.05

1.05

0.96–1.15

 

5-day average

 

1.05

1.01–1.09

1.04

1.00–1.09

1.09

0.98–1.22

O3 (Max)

Same day

18.0

1.02

0.97–1.07

1.00

0.92–1.07

1.05

0.98–1.12

 

1-day lag

 

1.05

1.00–1.10

0.99

0.92–1.06

1.09

1.03–1.16

 

3-day average

 

1.10

1.03–1.17

1.02

0.93–1.13

1.16

1.07–1.25

 

5-day average

 

1.10

1.03–1.17

1.04

0.93–1.16

1.14

1.05–1.24

PM2.5 ‡

Same day

6.3

1.04

1.00–1.07

1.02

0.96–1.08

1.04

1.00–1.09

 

1-day lag

 

1.02

0.98–1.06

1.00

0.94–1.06

1.03

0.98–1.07

 

3-day average

 

1.05

1.00–1.10

1.01

0.93–1.09

1.07

1.01–1.14

 

5-day average

 

1.06

1.00–1.12

0.99

0.91–1.09

1.10

1.02–1.17

PM10 ‡

Same day

16.0

1.06

1.02–1.10

1.04

0.98–1.11

1.07

1.02–1.13

 

1-day lag

 

1.04

1.00–1.08

1.02

0.96–1.09

1.04

1.00–1.09

 

3-day average

 

1.08

1.03–1.14

1.03

0.96–1.12

1.11

1.05–1.18

 

5-day average

 

1.09

1.03–1.15

1.02

0.93–1.11

1.14

1.06–1.22

  1. *Odds ratios were calculated in relation to an increase in the interquartile range (IQR) of selected air pollutants and were adjusted for relative humidity and temperature, and daily number of visits for influenza (all ages combined).
  2. ‡ Particulate data were only available between January 1, 1998 and December 31, 2002