### 1 Appendix A. Supplementa ry Data

Table S 1 . Selected national and regional air pollution control programs implemented since 2000

Scope Program or

Regulation Description Year phased in References

National National Tier 2

Vehicle and

Gasoline Sulfur

Program The tailpipe standards were set at an

average standard of 0.07 grams per mile

for nitrogen oxides for vehicles weighing

less than 6000 pounds. Refiners will meet

a 30 ppm average sulfur level with a

maximum cap of 80 ppm. 2004

- 2007 http://www.epa

.gov/tier2/

National Low

Emission Vehicle

Program and

Ozone Transport

Commission

(OTC) LEV NO

x will be reduced by 538 tons per day

nationwide in 2005 and 1,699 tons per

day in 2015. Non

- methane organic gases

(NMOG) will be reduced by 350 tons per

day nationwide in 2005 and 1,030 tons

per day in 2015. Since 2000 http://www.epa

.gov/oms/lev

nlev.htm#imple

mentation

Heavy

- Duty

Highway Diesel

Program 2.6 million tons of smog

- causing nitrogen

oxide emissions will be reduced each

year. Soot or PM will be reduced by

110,000 tons a year. 2007

- 2010 http://www.epa

.gov/oms/highw

ay

- diesel/

Acid Rain

Program Phase II The final 2010 SO 2 cap that may be

emitted by electric generating units

(EGUs) in the contiguous United States

was set at 8.95 million tons, a level of

about one

- half of the emissions from the

power sector in 1980. NO

x rule will

achieve an additional reduction of

890,000 to ns of NO

x annually, increasing

the overall annual reductions to 2.1

million tons. Since 2000 http://www.epa

.gov/airmarkets

/programs/arp/

Regional:

under the

Texas State

Implementation

Plan (SIP) Nitrogen

Oxides(NO

x )

Mass Emissions

Cap and Trade

(MECT) Overall 80% NO

x reduction from existing

industrial sources and utility power

plants, implemented through a cap and

trade program. 2003

- 2007

http://www.tce

q.state.tx.us/air

quality/sip/hgb/

sip

- hgb Texas Low

Emission Diesel

(TxLED) Requires all diesels for both on

- road and

non

- road use to have a lower aromatic

content and a higher cetane number. Since 2005

Texas Emissions

Reduction Plan Provides grant funds for on

- road and

non

- road heavy

- duty diesel engine

replacement/retrofit. Since 2002

### 2 Table S 2 . Descriptive statistics for PM 2.5 

### and its components in Greater Houston, Texas

, during 2000

- 2011.

Pollutant a Sampling period N Mean SD b IQR c Min P25 Median P75 Max

PM 2.5 1/01/2000

- 12/30/2005 2086 13.547 5.801 6.760 1.900 9.600 12.600 16.360 57.500

1/02/2006

- 12/30/2011 2072 13.448 5.443 6.775 2.100 9.600 12.600 16.375 44.200

1/01/2000

- 12/30/2011 4158 13.498 5.625 6.760 1.900 9.600 12.600 16.360 57.500

Al 2/15/2000

- 12/30/2005 630 0.071 0.192 0.037 0.001 0.005 0.010 0.041 1.866

1/02/2006

- 12/29/2011 688 0.100 0.212 0.058 0.003 0.013 0.031 0.071 1.720

2/15/2000

- 12/29/2011 1318 0.086 0.203 0.052 0.001 0.006 0.023 0.058 1.866

Br 2/15/2000

- 12/30/2005 630 0.003 0.002 0.003 0.000 0.002 0.003 0.004 0.023

1/02/2006

- 12/29/2011 688 0.003 0.004 0.003 0.000 0.002 0.003 0.004 0.076

2/15/2000

- 12/29/2011 1318 0.003 0.003 0.003 0.000 0.002 0.003 0.004 0.076

Cr 2/15/2000

- 12/30/2005 630 0.001 0.001 0.001 0.000 0.000 0.001 0.001 0.012

1/02/2006

- 12/29/2011 688 0.001 0.010 0.001 0.000 0.000 0.001 0.001 0.255

2/15/2000

- 12/29/2011 1318 0.001 0.007 0.001 0.000 0.000 0.001 0.001 0.255

Cu 2/15/2000

- 12/30/2005 630 0.003 0.005 0.003 0.000 0.001 0.002 0.004 0.095

1/02/2006

- 12/29/2011 688 0.012 0.022 0.010 0.000 0.001 0.002 0.011 0.197

2/15/2000

- 12/29/2011 1318 0.008 0.017 0.005 0.000 0.001 0.002 0.006 0.197

EC d 2/15/2000

- 12/30/2005 626 0.347 0.205 0.218 0.045 0.210 0.300 0.428 2.025

1/02/2006

- 4/13/2009 385 0.411 0.252 0.269 0.049 0.245 0.350 0.513 2.200

2/15/2000

- 4/13/2009 1011 0.372 0.226 0.235 0.045 0.220 0.315 0.455 2.200

Fe 2/15/2000

- 12/30/2005 630 0.079 0.112 0.048 0.002 0.027 0.042 0.075 0.979

1/02/2006

- 12/29/2011 688 0.092 0.134 0.056 0.001 0.032 0.052 0.088 1.120

2/15/2000

- 12/29/2011 1318 0.086 0.124 0.054 0.001 0.030 0.048 0.084 1.120

K 2/15/2000

- 12/30/2005 630 0.076 0.061 0.057 0.001 0.036 0.057 0.093 0.637

1/02/2006

- 12/29/2011 688 0.079 0.077 0.051 0.001 0.040 0.057 0.091 1.004

2/15/2000

- 12/29/2011 1318 0.077 0.070 0.054 0.001 0.038 0.057 0.092 1.004

Mn 2/15/2000

- 12/30/2005 630 0.002 0.002 0.001 0.000 0.001 0.001 0.002 0.014

1/02/2006

- 12/29/2011 688 0.002 0.002 0.002 0.000 0.001 0.002 0.003 0.022

2/15/2000

- 12/29/2011 1318 0.002 0.002 0.002 0.000 0.001 0.001 0.002 0.022

Na + 2/15/2000

- 12/30/2005 587 0.222 0.259 0.199 0.006 0.065 0.128 0.264 2.160

1/02/2006

- 12/29/2011 692 0.268 0.274 0.291 0.006 0.071 0.175 0.362 2.115

2/15/2000

- 12/29/2011 1279 0.247 0.268 0.253 0.006 0.068 0.157 0.321 2.160

NH 4 + 2/15/2000

- 12/30/2005 617 1.247 0.928 1.000 0.001 0.630 0.970 1.630 8.760

1/02/2006

- 12/29/2011 692 0.986 0.753 0.779 0.003 0.486 0.782 1.265 7.040

2/15/2000

- 12/29/2011 1309 1.109 0.850 0.881 0.001 0.550 0.875 1.430 8.760

Ni 2/15/2000

- 12/30/2005 630 0.002 0.002 0.001 0.000 0.001 0.001 0.002 0.035

1/02/2006

- 12/29/2011 688 0.002 0.003 0.001 0.000 0.001 0.001 0.002 0.066

2/15/2000

- 12/29/2011 1318 0.002 0.003 0.001 0.000 0.001 0.001 0.002 0.066

NO 3 - 2/15/2000

- 12/30/2005 623 0.784 0.752 0.531 0.036 0.371 0.542 0.902 5.840

1/02/2006

- 12/29/2011 692 0.755 0.602 0.464 0.022 0.404 0.586 0.868 4.800

2/15/2000

- 12/29/2011 1315 0.769 0.677 0.487 0.022 0.388 0.565 0.875 5.840

### 3 Table S 2 . Descriptive statistics for PM 2.5 

### and its components in Greater Houston, Texas

, during 2000

- 2011.

OC d 2/15/2000

- 12/30/2005 595 3.429 2.136 2.572 0.555 1.825 2.851 4.397 17.544

1/02/2006

- 4/13/2009 316 2.894 1.868 2.436 0.422 1.463 2.323 3.899 10.758

2/15/2000

- 4/13/2009 911 3.243 2.062 2.516 0.422 1.714 2.710 4.230 17.544

Si 2/15/2000

- 12/30/2005 630 0.229 0.402 0.136 0.002 0.062 0.104 0.197 4.067

1/02/2006

- 12/29/2011 688 0.255 0.466 0.164 0.002 0.050 0.095 0.214 3.920

2/15/2000

- 12/29/2011 1318 0.242 0.436 0.146 0.002 0.055 0.100 0.202 4.067

SO 4 2

- 2/15/2000

- 12/30/2005 623 3.707 2.419 2.510 0.003 2.100 3.194 4.610 26.000

1/02/2006

- 12/29/2011 692 2.950 1.637 2.065 0.002 1.735 2.613 3.800 10.400

2/15/2000

- 12/29/2011 1315 3.309 2.079 2.245 0.002 1.910 2.896 4.155 26.000

V 2/15/2000

- 12/30/2005 630 0.004 0.003 0.003 0.000 0.002 0.003 0.005 0.022

1/02/2006

- 12/29/2011 688 0.005 0.004 0.005 0.001 0.002 0.004 0.007 0.023

2/15/2000

- 12/29/2011 1318 0.004 0.004 0.004 0.000 0.002 0.004 0.006 0.023

Zn 2/15/2000

- 12/30/2005 630 0.008 0.010 0.008 0.000 0.003 0.005 0.011 0.122

1/02/2006

- 12/29/2011 688 0.008 0.008 0.007 0.000 0.003 0.005 0.010 0.099

2/15/2000

- 12/29/2011 1318 0.008 0.009 0.008 0.000 0.003 0.005 0.010 0.122

a 

### The unit for all pollutants is μg/m 3



### . b 

### Standard deviation. c 

### Interquartile range. d 

### We included a shorter sampling

period for EC and OC due to sampling method change in the year 2009 ( see Methods for details )

.

### 4 Table S 3 . Pearson correlation coefficients a 

### of PM 2.5 

### and its component s.

PM 2.5 Al NH 4 + Br Cr Cu Fe Mn Ni NO 3 - K Si SO 4 2

- V Zn Na + b EC b OC

PM 2.5 1.00

Al 0.28 1.00

NH 4 + 0.67

- 0.14 1.00

Br 0.34

- 0.15 0.30 1.00

Cr 0.00 0.03

- 0.02 0.02 1.00

Cu 0.06 0.00

- 0.01 0.01 0.23 1.00

Fe 0.33 0.92

- 0.11

- 0.12 0.20 0.07 1.00

Mn 0.34 0.69 0.02

- 0.01 0.29 0.17 0.79 1.00

Ni 0.13

- 0.05 0.19 0.14 0.70 0.17 0.08 0.24 1.00

NO 3 - 0.26

- 0.07 0.35 0.28 0.00 0.04

- 0.02 0.09 0.19 1.00

K 0.47 0.54 0.08 0.29 0.00 0.02 0.57 0.44

- 0.02 0.10 1.00

Si 0.31 0.93

- 0.12

- 0.15 0.01 0.01 0.95 0.67

- 0.07

- 0.05 0.57 1.00

SO 4 2

- 0.71

- 0.04 0.92 0.32

- 0.02

- 0.05

- 0.02 0.04 0.14 0.14 0.19

- 0.02 1.00

V 0.29 0.09 0.26 0.16 0.00 0.02 0.13 0.20 0.29 0.31 0.16 0.09 0.21 1.00

Zn 0.26

- 0.08 0.27 0.18 0.04 0.16 0.01 0.19 0.11 0.30 0.07

- 0.07 0.17 0.13 1.00

Na + 0.09 0.16

- 0.16 0.30

- 0.02

- 0.17 0.13 0.00

- 0.07

- 0.08 0.32 0.16 0.03 0.00

- 0.28 1.00

EC 0.31

- 0.10 0.22 0.19 0.25 0.22 0.02 0.25 0.18 0.34 0.06

- 0.10 0.11 0.30 0.60

- 0.32 1.00

OC 0.55

- 0.17 0.51 0.29 0.14 0.16

- 0.08 0.13 0.21 0.33 0.15

- 0.13 0.43 0.15 0.54

- 0.33 0.66 1.00

a 

### Data used to calculate these correlations include the entire sampling period from 2000 to 2011 ; b 

### EC and OC measurements

during 2001

- 2009 were used

.

### 5 Fig. S1. Federal Reference Method (FRM) PM 2.5 

### monitoring sites in Greater Houston , Texas

. ( Speciation

samples (red h exagon ) were collected at the Houston Deer Park site . Mass samples were collected from

16 sites within Greater Houston. Among them, 3 sites (blue triangles) have been operating actively

throughout the entire study period from 2000 to 2011. Other sites (red triangles) only operated for a

certain period of time during the study period).

### 6 Fig. S 2 . Boxplots of daily mean concentrations of PM 2.5 

### ma ss and major components by year ( EC and OC measurements during 2001

- 2009 were

used )

. PM2.5 NH4(+) NO3(-)

SO4(2-) EC OC 0 20 40 60

0.0 2.5 5.0 7.5

0 2 4 6

0 10 20

0.0 0.5 1.0 1.5 2.0

0 5 10 15 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011μg/m3

### 7 Fig. S 3 . Box

- plots of daily mean temperature and mean dew point temperature by season. Daily Mean Temperature Daily Mean Dew Point Temperature

0 10 20 30

-10 0 10 20

SP SU F W SP SU F Wcelsius (°C)

### 8 Fig. S 4

. Percent increase in mortality (95% CI) associated with an IQR increase in the PM 2.5 

### components on the previous day by sampling period.

All, period from 2000 to 2011; 1, period from 2 000 to 2005; 2, period from 2006 to 2011 (IQRs were calculated based on all

- year data ; Otherwise

as Fig. S 2 )

. PM2.5 Al Br Cr Cu EC

Fe K Mn Na(+) NH4(+) Ni

NO3(-) OC Si SO4(2-) V Zn -2 0 2

-2 0 2

-2 0 2

All 1 2 All 1 2 All 1 2 All 1 2 All 1 2 All 1 2Percent increase in mortality for IQR incre

### 9 Fig. S 5

. Percent increase in mortality (95% CI) associated with an IQR increase in the PM 2.5 

### components at lag time day 0, 1, 2, and 3 (Otherwise

as Fig. S 4 )

. PM2.5 Al Br Cr Cu EC

Fe K Mn Na(+) NH4(+) Ni

NO3(-) OC Si SO4(2-) V Zn -1 0 1

-1 0 1

-1 0 1

0 1 2 3 0 1 2 3 0 1 2 3 0 1 2 3 0 1 2 3 0 1 2 3Percent increase in mortality for IQR incre

### 10 Fig. S 6

. Percent increase in mortality (95% CI) associated with an IQR increase in the PM 2.5 

### components by age groups. Age groups: All, all ages

included; >=65, persons with the mortality age ≥ 65 ( Otherwise as Fig. S 4 )

. PM2.5 Al Br Cr Cu EC

Fe K Mn Na(+) NH4(+) Ni

NO3(-) OC Si SO4(2-) V Zn -2 -1 0 1 2

-2 -1 0 1 2

-2 -1 0 1 2

All >=65 All >=65 All >=65 All >=65 All >=65 All >=65Percent increase in mortality for IQR incre

### 11 Fig. S 7

. Percent increase in mortality (95% CI) associated with an IQR increase in the PM 2.5 

### components on the previous day by season in Greater

Housto n, Texas, during 2000

- 2011. Warm , (April

- September ); Cool, ( October

- M arch ) (Otherwise as Fig. S4)

. PM2.5 Al Br Cr Cu EC

Fe K Mn Na(+) NH4(+) Ni

NO3(-) OC Si SO4(2-) V Zn -1 0 1 2

-1 0 1 2

-1 0 1 2

Warm Cool Warm Cool Warm Cool Warm Cool Warm Cool Warm CoolPercent increase in mortality for IQR incre

### 12 Fig. S 8. Box

- plots of daily mean PM 2.5 

### mass and the major PM 2.5 

### components by season (Otherwise as Fig. S4)

. PM2.5 NH4(+) NO3(-)

SO4(2-) EC OC 0 20 40 60

0.0 2.5 5.0 7.5

0 2 4 6

0 10 20

0.0 0.5 1.0 1.5 2.0

0 5 10 15 SP SU F W SP SU F W SP SU F W

SP SU F W SP SU F W SP SU F Wμg/m3

### 13 Fig. S9. Wind roses based on measurements at the weather station located in at the George Bush

Intercontinental Airport , Houston, during 2000

- 2011. Spring Summer

Fall Winter W

S N

E 5% 10% 15% 20% 25% 30%

0 - 2 2 - 4 4 - 6 6 - 25

(m/s) W

S N

E 5% 10% 15% 20% 25%

0 - 2 2 - 4 4 - 6 6 - 25

(m/s)

W

S N

E

2% 4% 6% 8% 10% 12% 14

0 - 2 2 - 4 4 - 6 6 - 25

(m/s) W

S N

E

2% 4% 6% 8% 10% 12% 14%

0 - 2 2 - 4 4 - 6 6 - 25

(m/s)