1. The Health Effects of Automobile Fuel Economy Standard Through Improving Air Quality Qing Shi UNCG 2015

2. Background Automobile driving has externalities (eg. air population) Fuel economy standard - Corporate Average Fuel Economy (CAFE) plays the primary role in US to regular mobile source pollution Health effects of CAFE standard?

3. Research Questions Does fuel economy standard lead to better health outcomes? Is there evidence for air pollution as the mechanism (mediator) Welfare gain/lost of CAFE Policy advice More fuel efficient cars Less air pollutants Better Health Outcome Less Fuel consumption

4. Statistical Mediation Effects Baron and Kenny's (1986) steps 1.Y =  X (path C) 2.M ~  X (path A) 3.Y ~  M +  X (path A B)  <  Significant  Source(X) Outcome (Y) Mediator (M) A B C Empirical models

5. Data Vehicle and fuel sales data (US DOT Highway Statistics) State level vehicle miles, fuel consumption and derived MPG 2001 – 2011, state-year panel Air Quality System Data (US EPA AQS) County level annual  average to state level PM2.5, Carbon monoxide, Nitrogen dioxide 2001 – 2013, state-year panel Behavioral Risk Factor Surveillance Survey (BRFSS) Asthma incidence/status 2003 – 2011, state-year pooled cross section

6. Automobile Fuel Economy improvement Data source: US DOT NTSUS DOT NTS

10. PM2.5 Averaged Across States

11. Econometric models

12. Empirical Approach Run Stepwise logit model select significant Xs, every year Run logit regression of Asthma on MPG + X Run logit regression of asthma on pollutants and MPG + X Run OLS of Pollutants on MPG

13. Individual Characteristics Weight Body Mass Index – BMI BMI Categories – normal, overweight, obese Income Level - 50K Gender, Race Smoking status Age, Age category - =65 Has healthcare coverage

14. Summary Statistics of Model Variables 1. BRFSS (individual, 2001 ~2012) N = 3297711, after data cleaning Variablemeanstd. dev.minmedianmax Health Outcomes Has Asthma0.08790.2831001 Has COPD0.07970.2708001 Has Diabetes0.10740.3097001 Demographics Age53.5017.26185499 Age > 650.2840.451001 Current Smoker0.1840.387001 Caucasian0.8540.353011 Female0.6140.487011 Has Healthcare coverage0.8840.320011 Education status4.7921.080156 Income level3.5771.463145 Weight (lb)178.875.40170999 Body Mass Index30.1314.824.7826.6699.99

15. 2. State level Aggregate N = 490, after data cleaning From vehicles of surveyee Variablemeanstd. dev.minmedianmax Health Outcomes Has Asthma0.08670.01140.05270.08600.1243 Has Diabetes0.10200.02720.04430.09980.1812 Air Pollutants PM2.5 - the 98%27.736.76812.3727.27565.5 PM2.5 - Annual Mean10.632.4225.46210.54517.06 CO - the 2nd highest3.772.8190.23.31833.5 CO - the 2nd highest 8-hour average2.221.5210.32.0524.3 NO2 - the 98%44.83014.4141043.556182 Average fuel economy (MPG)*22.422.90315.4222.0640.97 Demographic, State average Age52.713.33144.33153.27759.509 Age > 650.2710.0580.1390.27710.424 Current Smoker0.1910.0360.0880.1900.311 Caucasian0.8530.0960.4310.8650.982 Female0.6120.0270.4960.6110.700 Has Healthcare coverage0.8830.0340.7700.8870.961 Education status4.7830.1734.1784.7915.336 Income level3.5680.2402.9693.5584.069 Weight (lb)180.912.49164.82175.9217.60 Body Mass Index30.131.3926.5730.4833.12

16. Model Estimates 1. Pollutants on MPG change (Fixed effects* model) PM2.5 - the 98% PM2.5 - Annual Mean CO - the 2nd highest 1-hour measure CO - the 2nd highest 8-hour averageNO2 - the 98% Intercept29.16 2.22 <.0001 11.06 0.8641 <.0001 0.508 1.003 0.6125 0.618 0.434 0.155 41.47 5.375 <.0001 MPG-0.35036 0.0975 0.0004 -0.1069 0.0379 0.005 0.104 0.0443 0.0185 0.0346 0.0191 0.0734 -0.632 0.2373 0.0008 GDP (per Capita) 0.000077 0.000017 <.0001 0.000021 6.73E-06 0.0017 -0.00001 7.82E-06 0.1063 2.24E-06 3.39E-06 0.5078 0.00294 0.000042 <.0001 * From 49 States and DC, 1995 - 2011

17. Model Estimates 2. Asthma on PM1, PM2, CO1, CO2, NO and MPG, Model estimates in 2003, control for demographic characteristics (all sig. at 0.0001)

18. Conclusion Statistically Significant effect of Fuel Economy on Asthma Statistically Significant effect of PM2.5 and CO on Asthma Statistically Significant effect of Fuel Economy on Air pollutants Empirical evidence of the link among More efficient cars Less air pollutants Better Health Outcome

19. Appendix Summary Statistics of Data

20. Summary Statistics 1. Vehicle Miles Traveled Data Yearmeanstd. dev.minmedianmax 199547,50549,2703,46538,489276,371 199648,67150,0663,31638,095278,043 199750,20351,7753,32638,840285,612 199851,53252,9553,30740,261290,630 199952,77154,3973,46241,205300,066 200053,91856,1013,49841,771306,649 200154,85056,9783,75043,244310,575 200255,99558,6443,54743,545320,942 200356,68459,4024,15044,156323,592 200458,08861,0473,74245,891328,917 200558,62461,5463,71347,019329,267 200659,10061,6813,62347,742327,478 200759,40862,0533,60947,572328,312 200858,30460,9663,61147,534327,286 200957,97660,2523,60846,230324,486 201058,18260,2793,59146,940322,849 201157,85159,8983,56846,606320,784 201258,22460,3973,57246,889326,272 201358,59561,2223,52746,996329,534 * 51 Observations (States, DC) per year Unit: Million Miles

21. Summary Statistics 2. Motor Fuel Consumption Data Yearmeanstd. dev.minmedianmax 19952,819,2942,814,409172,5792,242,01815,211,262 19962,891,1942,894,570160,3232,357,79715,511,709 19972,955,1412,945,592167,9052,316,54215,874,325 19983,047,1633,041,332166,0712,409,44616,213,447 19993,154,1833,154,373167,1372,480,22816,777,135 20003,181,8793,221,068167,1752,529,56817,080,595 20013,216,6553,293,103151,6322,748,23117,460,517 20023,319,3333,429,090151,4182,601,28618,297,028 20033,350,9313,401,700143,4472,722,40617,795,916 20043,433,3973,523,439147,1752,582,30518,647,180 20053,437,2783,563,084150,0292,629,39418,860,547 20063,465,7003,576,027126,8452,642,08718,711,279 20073,479,6113,605,670130,4852,703,81018,842,520 20083,360,8893,474,344110,4982,733,26317,829,713 20093,307,7743,399,097114,0242,560,72617,450,012 20103,348,5583,438,297108,0812,690,58117,464,647 20113,308,2663,415,52895,9122,601,60817,233,778 20123,318,0933,438,66795,5662,728,07017,118,279 20133,348,0233,490,11389,2102,725,96017,287,862 * 51 Observations (States, DC) per year Unit: Thousand Miles

22. Summary Statistics 3. Fuel Economy Data Yearmeanstd. dev.minmedianmax 199516.481.5512.7316.5320.08 199616.551.5513.0416.6220.68 199716.591.6113.0316.6121.40 199816.601.5812.6616.8020.39 199916.511.7611.4216.4120.85 200016.721.7412.8716.6621.49 200117.072.2212.2316.9324.73 200216.841.9613.4516.7323.54 200316.922.3013.0116.6628.93 200416.782.1311.0116.8825.43 200516.932.1610.8916.7324.75 200617.012.4210.6216.9928.56 200716.992.3711.1216.9627.66 200817.322.9310.7217.3932.68 200917.472.8610.0317.7431.64 201017.343.0010.5517.5433.23 201117.523.4210.1517.6137.20 201217.623.4512.1517.6537.38 201317.713.7012.0417.5439.54 * 51 Observations (States, DC) per year Unit: Miles Per Gallon

23. Summary Statistics 4. Air Pollutants (PM 2.5 ) Data * 49 Observations per Year (48 States and DC) Variable Yearmeanstd. dev.minmedianmax PM2.5 - the 98% of the daily 200132.397.82117.2530.9056.71 average 200230.908.04015.530.4556 200329.866.21918.8129.1843.5 200429.477.33815.528.5865.5 200531.996.531163343.13 200628.195.16116.6228.2539 200729.125.97214.7529.8849 200825.574.84915.1225.4533.07 200924.065.21212.3723.4437.25 201024.844.72615.4224.2937.25 201124.304.43215.3724.0834.4 201222.073.39616.521.5829.8 PM2.5 - the Weighted Annual Mean 200112.122.7476.512.4917.06 200211.402.6355.7611.4316.3 200311.322.4996.6611.5815.59 200411.042.3135.8511.18915.04 200511.942.7825.7611.8116.62 200610.932.2516.261115.37 200711.172.3376.1411.0415.68 200810.191.9035.8810.5113.37 20099.271.6065.469.3612.6 20109.701.9395.649.6113.54 20119.491.7445.469.4912.39 20129.081.4056.279.0811.73