... region. 38 For ease of interpretation, all pollutants have been standardized to have a mean of zero and standard deviation of one. 20mainly comes from vehicle exhaust, a likely explanation ... Krupnick, Alan, Winston Harrington, and Bart Ostro, “Ambient Ozone and Acute Health Effects: Evidence from Daily Data,” Journal of Environmental Economics and Management 18, 1-18 (1990). Managed ... Portney, Paul and John Mullahy, “Urban Air Quality and Acute Respiratory Illness,” Journal of Urban Economics, 20, 21-38 (1986). Portney, Paul and John Mullahy, “Urban Air Quality and Chronic Respiratory...