1

Supplemental Material: Seasonal and Regional Short-term Effects of Fine Particles 

on Hospital Admissions in 202 US Counties, 1999-2005 

American Journal of Epidemiology (Bell et al.) 

Figure S1. Boxplots of cause-specific hospital admissions rates, by region and season 

(average admissions/day/100,000 persons) 
2

Figure S2. Boxplots of PM2.5, temperature, and dew point temperature by region and 

season (μg/m3, oF) 
Figure S3. Percent increase in total cardiovascular admissions per 10 μg/m3 in same day (lag 0) PM2.5 by region 

harmonic model (in black) and seasonal interaction model (in red) 

Note: The vertical lines mark the divisions among seasons as defined by the seasonal interaction model. Solid lines represent the centra

lines represent the 95% posterior interval. The number in parentheses (n) represents the number of counties included in each region. No

axis is identical across regions. The 95% intervals for some regions are too large to fit on this scale (e.g., Northwest region for harmonifor a version of these figures with a different y-axis scale. 
Figure S4. Percent increase in total respiratory admissions per 10 μg/m3 in same day (lag 0) PM2.5 by region for rharmonic model (in black) and seasonal interaction model (in red) Note: The vertical lines mark the divisions among seasons as defined by the seasonal interaction model. Solid lines represent the centra

lines represent the 95% posterior interval. The number in parentheses (n) represents the number of counties included in each region. No

axis is identical across regions. The 95% intervals for some regions are too large to fit on this scale (e.g., Northwest region for harmonifor a version of these figures with a different y-axis scale. 
Figure S5. Percent increase in total cardiovascular admissions per 10 μg/m3 in same day PM2.5 by region for resumodel (in black) and seasonal interaction model (in red) Note: The vertical lines mark the divisions among seasons as defined by the seasonal interaction model. Solid lines represent the centra

lines represent the 95% posterior interval. The number in parentheses (n) represents the number of counties included in each region. No

axis differs across regions. 

0 100 200 300

-10 -5 0 5 10

g( )

Day of year

percent

Winter Spring Summer Autumn Winter

0 100 200 300

-10 -5 0 5 10

Harmonic Curve Southwest US for CVD Lag 0 (n= 25 )

Day of year

percent

Winter Spring Summer Autumn Winter

0 100 200 300

-2 -1 0 1 2

Day of year

percent

Winter Spring Summer Autumn 

0 100 200 300

-2 -1 0 1 2

Harmonic Curve Southeast US for CVD Lag 0 (n= 58 )

Day of year

percent

Winter Spring Summer Autumn Wint

Northwest (n=9) Northeast (n=108)

Southwest (n=25) Southeast (n=58)

0 100 200 300

-10 -5 0 5 10

g( )

Day of year

percent

Winter Spring Summer Autumn Winter

0 100 200 300

-10 -5 0 5 10

Harmonic Curve Southwest US for CVD Lag 0 (n= 25 )

Day of year

percent

Winter Spring Summer Autumn Winter

0 100 200 300

-2 -1 0 1 2

Day of year

percent

Winter Spring Summer Autumn 

0 100 200 300

-2 -1 0 1 2

Harmonic Curve Southeast US for CVD Lag 0 (n= 58 )

Day of year

percent

Winter Spring Summer Autumn Wint

Northwest (n=9) Northeast (n=108)

Southwest (n=25) Southeast (n=58)
Figure S6. Percent increase in total respiratory admissions per 10 μg/m3 in lag 0 PM2.5 by region for results from 

(in black) and seasonal interaction model (in red) 

Note: The vertical lines mark the divisions among seasons as defined by the seasonal interaction model. Solid lines represent the centra

lines represent the 95% posterior interval. The number in parentheses (n) represents the number of counties included in each region. No

axis differs across regions.

0 100 200 300

-20 -15 -10 -5 0 5 10 15

g( )

Day of year

percent

Winter Spring Summer Autumn Winter

0 100 200 300

-20 -15 -10 -5 0 5 10 15

Harmonic Curve Southwest US for RESP Lag 0 (n= 25 )

Day of year

percent

Winter Spring Summer Autumn Winter

0 100 200 300

-2 0 2 4

Day of year

percent

Winter Spring Summer Autumn 

0 100 200 300

-2 0 2 4

Harmonic Curve Southeast US for RESP Lag 0 (n= 58 )

Day of year

percent

Winter Spring Summer Autumn 

Northwest (n=9) Northeast (n=108)

Southwest (n=25) Southeast (n=58)

0 100 200 300

-20 -15 -10 -5 0 5 10 15

g( )

Day of year

percent

Winter Spring Summer Autumn Winter

0 100 200 300

-20 -15 -10 -5 0 5 10 15

Harmonic Curve Southwest US for RESP Lag 0 (n= 25 )

Day of year

percent

Winter Spring Summer Autumn Winter

0 100 200 300

-2 0 2 4

Day of year

percent

Winter Spring Summer Autumn 

0 100 200 300

-2 0 2 4

Harmonic Curve Southeast US for RESP Lag 0 (n= 58 )

Day of year

percent

Winter Spring Summer Autumn 

Northwest (n=9) Northeast (n=108)

Southwest (n=25) Southeast (n=58)