Figure 1. Map Showing City Limits, Pico y Placa Restricted Zone, and Monitoring Station Locations. CO not measured at Los Chillos (G) and Tumbaco (H). 36 Table 1. Summary Statistics for Hourly CO Concentrations (mg/m³). Observations Mean Median Std. Dev. Min. Max. Belisario† 42215 0.88 0.77 0.49 0 4.62 Centro† 42172 0.86 0.75 0.49 0 8.38 42384 41917 42406 0.81 0.58 0.60 0.71 0.50 0.54 0.50 0.36 0.30 0 0 0 5.53 6.51 6.43 Camal† El Carapungo Guamani †Indicates stations inside restricted zone. Table 2. Correlation Coefficients for Hourly CO Concentrations across Stations. Belisario† Belisario† Centro† Camal† El Carapungo Guamani †Indicates Centro† El Camal† Carapungo Guamani 1 0.53 0.48 1 0.23 1 1 0.71 1 0.56 0.38 0.39 0.77 0.51 0.49 stations inside restricted zone. 37 correlation coefficient .8 .6 .4 .2 0 5 10 15 20 25 30 distance (km) between stations inside PyP zone between stations inside and outside PyP zone between stations outside PyP zone Figure 2. Distance between Stations and Correlation of Hourly CO Concentrations. CO concentrations 2 1.5 1 .5 0 2 4 6 8 10 12 14 16 18 20 hour of day Weekdays Saturdays Sundays Note: Vertical lines indicate restricted hours: 7:00 - 9:30 am and 4:00 - 7:30 pm. Figure 3. Diurnal Variation in CO Concentration at Centro. 38 22 24 Belisario logCO concentrations .75 .25 -.25 -.75 -1.25 2005 2006 2007 2008 2009 2010 2011 2012 2009 2010 2011 2012 2009 2010 2011 2012 Centro logCO concentrations .75 .25 -.25 -.75 -1.25 2005 2006 2007 2008 El Camal logCO concentrations .75 .25 -.25 -.75 -1.25 2005 2006 2007 2008 year peak-hours off-peak hours nighttime hours Note: Vertical lines indicate the introduction of PyP. Figure 4a. Annual Averages of log CO for Selected Working-Day Hours—Stations Inside Restricted Zone. 39 Carapungo logCO concentrations .75 .25 -.25 -.75 -1.25 2005 2006 2007 2008 2009 2010 2011 2012 2009 2010 2011 2012 Guamani logCO concentrations .75 .25 -.25 -.75 -1.25 2005 2006 2007 2008 year peak-hours off-peak hours nighttime hours Note: Vertical lines indicate the introduction of PyP. Figure 4b. Annual Averages of log CO for Selected Working-Day Hours—Stations Outside Restricted Zone. 40 Table 3. Effect of PyP on Peak-Hours Pollution on Working Days: DD Estimates with Off-Peak-Hours Pollution as Control. Belisario (1) (2) (3) (4) -0.0571*** (0.0122) -0.0572*** (0.0123) -0.0596*** (0.0122) -0.0593*** (0.0101) -0.1116*** (0.0123) -0.1101*** (0.0124) -0.1091*** (0.0123) -0.1004*** (0.0114) -0.1372*** (0.0155) -0.1375*** (0.0154) -0.1375*** (0.0154) -0.1462*** (0.0127) no no no yes no no yes yes no yes yes yes Centro El Camal Day-Hour Fixed Effects Year-Month Fixed Effects Weather Covariates Note: Standard errors are clustered at the week level. * p<0.05, ** p<0.01, *** p<0.001. Table 4. Robustness Tests of Effect of PyP on Peak-Hours Pollution on Working Days: DD Estimates for Preferred Specification with Off-Peak-Hours Pollution as Control. Year-Week Fixed Effects Symmetric Sample Curtailed Peak Hours -0.0582*** (0.0100) -0.0548*** (0.0109) -0.0552*** (0.0085) -0.0984*** (0.0114) -0.0973*** (0.0115) -0.0844*** (0.0105) -0.1391*** (0.0130) -0.1557*** (0.0144) -0.1463*** (0.0118) Belisario Centro El Camal Note: Standard errors are clustered at the week level. * p<0.05, ** p<0.01, *** p<0.001. 41 Table 5. Placebo Tests Using Non-Working Days of Effect of PyP on PeakHours Pollution on Working Days: DD Estimates with Off-Peak-Hours Pollution as Control. (1) (2) (3) (4) -0.0014 (0.0126) -0.0027 (0.0127) -0.0159 (0.0164) -0.0181 (0.0142) Centro -0.0579*** (0.0150) -0.0590*** (0.0148) -0.0605*** (0.0147) -0.0485*** (0.0134) El Camal -0.0534** (0.0170) -0.0560*** (0.0167) -0.0611*** (0.0169) -0.0321 (0.0167) no no no yes no no yes yes no yes yes yes Belisario Day-Hour Fixed Effects Year-Month Fixed Effects Weather Covariates Note: Standard errors are clustered at the week level. * p<0.05, ** p<0.01, *** p<0.001. Table 6. Placebo Tests Using Stations Outside Restricted Zone of Effect of PyP on PeakHours Pollution on Working Days: DD Estimates with Off-Peak-Hours Pollution as Control. Carapungo (1) (2) (3) (4) -0.0683*** (0.0116) -0.0674*** (0.0114) -0.0675*** (0.0113) -0.0346** (0.0120) 0.0029 (0.0091) 0.0025 (0.0091) 0.0026 (0.0090) 0.0089 (0.0096) no no no yes no no yes yes no yes yes yes Guamani Day-Hour Fixed Effects Year-Month Fixed Effects Weather Covariates Note: Standard errors are clustered at the week level. * p<0.05, ** p<0.01, *** p<0.001. 42 Table 7. Effect of PyP on Evening Peak-Hours Pollution on Working Days: DD Estimates with Off-Peak-Hours Pollution as Control. Belisario (1) (2) (3) (4) -0.0438** (0.0166) -0.0443** (0.0167) -0.0451** (0.0166) -0.0622*** (0.0124) -0.1159*** (0.0168) -0.1164*** (0.0168) -0.1160*** (0.0168) -0.1101*** (0.0138) -0.0875*** (0.0195) -0.0879*** (0.0193) -0.0879*** (0.0192) -0.1297*** (0.0138) no no no Yes No No yes yes no yes yes yes Centro El Camal Day-Hour Fixed Effects Year-Month Fixed Effects Weather Covariates Note: Standard errors are clustered at the week level. * p<0.05, ** p<0.01, *** p<0.001. Table 8. Placebo Tests Using Stations Outside Restricted Zone of Effect of PyP on Evening Peak-Hours Pollution on Working Days: DD Estimates with Off-Peak-Hours Pollution as Control. Carapungo (1) (2) (3) (4) 0.0177 (0.0152) 0.0191 (0.0150) 0.0203 (0.0149) 0.0018 (0.0139) 0.0195 (0.0196) 0.0197 (0.0197) 0.0195 (0.0197) 0.0004 (0.0191) no no no yes no no yes yes no yes yes yes Guamani Day-Hour Fixed Effects Year-Month Fixed Effects Weather Covariates Note: Standard errors are clustered at the week level. * p<0.05, ** p<0.01, *** p<0.001. 43 Table 9. Effect of PyP on Peak-Hours Pollution on Working Days: Pooled DD and DDD Estimates. (1) (2) (3) (4) Pooled DD Inside -0.1018*** (0.0095) -0.1014*** (0.0095) -0.1021*** (0.0095) -0.1017*** (0.0081) Pooled DD Outside -0.0324*** (0.0079) -0.0322*** (0.0078) -0.0323*** (0.0077) -0.0127 (0.0083) Pooled DDD -0.0693*** (0.0100) -0.0691*** (0.0101) -0.0699*** (0.0101) -0.0890*** (0.0104) no no no no yes yes no no yes yes yes no yes yes yes yes Station FE Station-Specific Day-Hour FE Station-Specific Year-Month FE Station-Specific Weather Covariates Note: Standard errors are clustered at the week level, with all stations in the same cluster. * p<0.05, ** p<0.01, *** p<0.001. Table 10. Robustness Tests of Effect of PyP on Peak-Hours Pollution on Working Days: DDD Estimates for Preferred Specification. Pooled DDD Year-Week Fixed Effects Symmetric Sample Curtailed Peak Hours Without Carapungo -0.0878*** (0.0102) -0.0822*** (0.0111) -0.0648*** (0.0077) -0.1062*** (0.0114) Note: Standard errors are clustered at the week level, with all stations in the same cluster. * p<0.05, ** p<0.01, *** p<0.001. 44 Table 11. Effect of PyP on Pollution Inside Restricted Zone on Working Days: DD Estimates with Pollution Outside Restricted Zone as Control. Peak Hours (7 – 9 am and 4 – 7 pm) Between Peak Hours (10 am – 3 pm) Extended Daytime Hours (6 am – 8 pm) Nighttime Hours (9 pm – 5 am) Station FE Station-Specific Day-Hour FE Year-Month FE Station-Specific Weather Covariates (1) (2) (3) (4) -0.1330*** (0.0227) -0.0671* (0.0295) -0.0971*** (0.0238) 0.1185*** (0.0317) -0.1332*** (0.0228) -0.0690* (0.0297) -0.0971*** (0.0240) 0.1201*** (0.0320) -0.1330*** (0.0229) -0.0675* (0.0297) -0.0965*** (0.0240) 0.1214*** (0.0323) -0.1121*** (0.0233) -0.0044 (0.0341) -0.0653* (0.0257) 0.1362*** (0.0340) no no no no yes yes no no yes yes yes no yes yes yes yes Note: Standard errors are clustered at the week level, with all stations in the same cluster. * p<0.05, ** p<0.01, *** p<0.001. Table 12. Robustness Tests of Effect of PyP on Pollution Inside Restricted Zone on Working Days: DD Estimates for Preferred Specification with Pollution Outside Restricted Zone as Control. Peak Hours (7 – 9 am and 4 – 7 pm) Between Peak Hours (10 am – 3 pm) Extended Daytime Hours (6 am – 8 pm) Nighttime Hours (9 pm – 5 am) Year-Week Fixed Effects Symmetric Sample Curtailed Peak Hours -0.1156*** (0.0232) -0.0124 (0.0338) -0.0681** (0.0255) 0.1309*** (0.0343) -0.1189*** (0.0255) 0.0131 (0.0378) -0.0642* (0.0281) 0.0811* (0.0358) -0.1436*** (0.0237) Note: Standard errors are clustered at the week level, with all stations in the same cluster. * p<0.05, ** p<0.01, *** p<0.001. 45 Table 13. Placebo Tests Using Non-Working-Days of Effect of PyP on Pollution Inside Restricted Zone on Working Days: DD Estimates with Pollution Outside Restricted Zone as Control. (1) Peak Hours (7 – 9 am and 4 – 7 pm) Between Peak Hours (10 am – 3 pm) Extended Daytime Hours (6 am – 8 pm) Nighttime Hours (9 pm – 5 am) Station FE Station-Specific Day-Hour FE Year-Month FE Station-Specific Weather Covariates (2) (3) (4) -0.0480 -0.0495 -0.0526 -0.0424 (0.0274) -0.0629 (0.0332) -0.0496 (0.0284) 0.0949* (0.0376) (0.0278) -0.0622 (0.0335) -0.0504 (0.0288) 0.0945* (0.0380) (0.0279) -0.0667* (0.0338) -0.0536 (0.0289) 0.1026** (0.0374) (0.0273) -0.0359 (0.0372) -0.0429 (0.0297) 0.0892* (0.0390) no no no no yes yes no no yes yes yes no yes yes yes yes Note: Standard errors are clustered at the week level, with all stations in the same cluster. * p<0.05, ** p<0.01, *** p<0.001. Table 14. Change in 2012 of Effect of PyP on Peak-Hours Pollution on Working Days: DD Estimates with Off-Peak-Hours Pollution as Control. Pre-2012 Effect of PyP Change in Effect in 2012 Total Effect in 2012 Belisario -0.0714*** (0.0110) 0.0321* (0.0126) -0.0394** (0.0128) Centro -0.1155*** (0.0124) 0.0408** (0.0139) -0.0747*** (0.0143) El Camal -0.1545*** (0.0147) 0.0221 (0.0157) -0.1324*** (0.0147) Pooled -0.1135*** (0.0091) 0.0317** (0.0102) -0.0819*** (0.0099) Note: Standard errors are clustered at the week level. * p<0.05, ** p<0.01, *** p<0.001. 46 Belisario† El Camal† Carapungo Los Chillos Belisario† El Camal† Carapungo Los Chillos Belisario† El Camal† Carapungo Los Chillos Belisario† El Camal† Carapungo Los Chillos Wind Direction (angular degree) Precipitation (millimeters) Solar Radiation (watts per square meter) Atmospheric Pressure (millibars) 43302 43493 43194 43344 43488 43551 43444 43388 43712 43716 43616 43575 42845 43246 42972 43269 43349 43334 43438 43336 43469 43536 43427 43347 43470 43534 43417 43350 Observations 726.06 726.38 742.55 759.09 192.53 196.51 211.76 214.46 0.14 0.15 0.08 0.16 146.71 150.41 250.55 196.63 1.78 1.82 1.73 1.57 70.95 69.95 73.23 72.89 13.68 13.94 14.32 15.53 Mean 726.18 726.32 742.48 759.43 10 2.08 2.97 1.72 0 0 0 0 149.49 159.82 269.93 182.83 1.56 1.58 1.27 1.20 72.68 72.58 77.39 79.40 12.82 13.06 13.11 14.13 Median 1.34 4.27 1.58 2.03 286.87 291.14 300.90 317.73 0.88 1.04 0.68 1.21 91.23 93.83 84.70 110.29 0.91 0.97 1.26 1.10 19.67 17.40 18.42 21.40 3.21 2.99 3.43 4.13 Std. Dev. 721.22 720.24 736.45 745.89 0 0 0 0 0 0 0 0 0 0.01 0 0 0 0.02 0.02 0 4.94 8.60 7.69 10.96 5.98 7.06 6.22 5.40 Min. 743.20 865.75 749.91 765.57 1250.68 1237.35 1289.26 1279.65 47.90 45.20 37.40 45.50 360 360 359.99 360 14.63 6.71 9.66 9.24 100 98.51 100 100 23.66 23.84 24.71 27.87 Max. 47 Notes: Meteorological data for Belisario and Los Chillos are used for Centro and Guamani, respectively. Wind direction is converted to one of eight dummy variables representing the eight principal wind directions. †Indicates stations inside restricted zone. Belisario† El Camal† Carapungo Los Chillos Wind Speed (meters per second) El Camal† Carapungo Los Chillos Belisario† Belisario† El Camal† Carapungo Los Chillos Relative Humidity (percent) Temperature (Celsius) Table A-1. Summary Statistics for Meteorological Variables. Appendix 0.3867*** (0.0093) -0.1096*** (0.0278) -0.2025*** (0.0190) 18168 0.1384 Peak After Constant N Adj. R2 Tuesday Wednesday Thursday Friday 0.0935** (0.0357) 0.0543 (0.0364) 0.0574 (0.0367) -0.0280 (0.0360) -0.0537 (0.0364) -0.0069 (0.0369) 10 11 12 13 14 15 Day-of-Week 20 0.2185*** (0.0330) 9 Weather Variables Indicatorsb 19 0.3911*** (0.0296) 8 48 0.1522*** (0.0277) 0.0607* (0.0277) 0.0389 (0.0277) 0.1197*** (0.0266) 0.1850*** (0.0317) 0.3231*** (0.0314) 0.3044*** (0.0340) (Relative Humidity)3 (Relative Humidity)2 Relative Humidity (Solar Radiation)4 (Solar Radiation)3 (Solar Radiation)2 Solar Radiationc Temperature4 Temperature3 Temperature2 0.2014*** (0.0342) 17 18 Temperature 0.1086** (0.0344) 16 0.5172*** (0.0242) -0.1004*** (0.0114) 7 Hour-of-Day Indicatorsa Peak*After Panel 2: Preferred Specification. Estimates for year-month fixed effects and day-of-week/hour-of-day interactions omitted. -0.1116*** (0.0123) Peak*After Panel 1: Simplest Specification -0.0000* (0.0000) 0.0014** (0.0004) -0.0476** (0.0140) -0.0001* (0.0000) 0.0020* (0.0009) -0.0143* (0.0067) 0.0503* (0.0193) -0.0001 (0.0000) 0.0034* (0.0016) -0.0791* (0.0366) 0.7209* (0.3540) Table A-2. Selected Estimates from Regressions Examining Effect of PyP on Peak-Hours Pollution on Working Days at Centro: DD with Off-Peak Hours Pollution as Control. N NE E SE S -0.0116 (0.0059) 0.0008 (0.0006) -0.0000 (0.0000) 0.0050 (0.0113) -0.0152* (0.0075) Precipitation2 Precipitation3 Precipitation4 Precipitation Dummy Atmospheric Pressure NW (Wind Speed)3 (interacted with wind direction) N NE E SE -0.1878 (0.1603) -0.2043 (0.1579) -0.1855 (0.1481) -0.0609 (0.1407) -0.0567 (0.1726) 0.7842** (0.2845) 17770 0.6770 NE E SE S SW W N Adj. R2 Note: Standard errors are clustered at the week level. a 6 am is the reference time. b Monday is the reference day. c Solar radiation is rescaled by dividing by 100. * p<0.05, ** p<0.01, *** p<0.001. W -0.0503 (0.1547) N SW (Wind Speed)2 (interacted with wind direction) 0.0584** (0.0189) Precipitation Wind Speed (interacted with wind direction) NW 0.0000 (0.0000) (Relative Humidity)4 Table A-2. (Continued) 49 0.0560* (0.0264) 0.0550* (0.0278) 0.0327 (0.0286) 0.0644* (0.0278) -1.4809*** (0.2775) -1.4906*** (0.3683) -0.0779 (0.1250) -0.1596 (0.0829) -0.1175 (0.0947) -0.0980 (0.1035) -0.0472 (0.1050) -0.1605 (0.1006) 0.7703** (0.2476) Constant NW W SW S SE E NE N (Wind Speed)4 (interacted with wind direction) NW W SW S 9.3009 (5.6832) -0.0874*** (0.0171) -0.0903** (0.0280) 0.0002 (0.0038) -0.0036 (0.0019) -0.0058* (0.0026) -0.0062* (0.0026) -0.0037 (0.0027) -0.0069* (0.0027) 0.6592*** (0.1207) 0.6678*** (0.1798) 0.0124 (0.0372) 0.0496* (0.0208)
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