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Table 1

The five health-related ozone metrics and a description of their calculation (see also Lefohn et al., 2017a). DOI: https://doi.org/10.1525/elementa.273.t1

MetricDescriptionAveraging periodUnits

 
a) 4MDA8 The 8-hour running mean for a particular hour is calculated on the mixing ratios for that hour plus the following 7 hours between the hours of 0700 and 2300 local time. For a given day the greatest of these 17 values is the daily maximum 8-hour average ozone. Based on all warm-season daily maximum 8-hour average ozone values the 4th highest value is selected. Warm season (6 month) ppb 
b) NDGT70 Annual count of number of days of MDA8 > 70 ppb. Annual days 
c) SOMO35 The sum of the positive differences between the daily maximum 8-h ozone mixing ratio and the cut-off value set at 35 ppb (70 μg m–3) calculated for all days in a year. Annual summation ppb × days 
d) 3MMDA1 Annual maximum of the three-month average of daily 1-hour maximum ozone value. Three month running mean values calculated were assigned to the mid-point of the 3 month period. Annual ppb 
e) AVGMDA8 6-month warm season mean of MDA8. Warm season ppb 
MetricDescriptionAveraging periodUnits

 
a) 4MDA8 The 8-hour running mean for a particular hour is calculated on the mixing ratios for that hour plus the following 7 hours between the hours of 0700 and 2300 local time. For a given day the greatest of these 17 values is the daily maximum 8-hour average ozone. Based on all warm-season daily maximum 8-hour average ozone values the 4th highest value is selected. Warm season (6 month) ppb 
b) NDGT70 Annual count of number of days of MDA8 > 70 ppb. Annual days 
c) SOMO35 The sum of the positive differences between the daily maximum 8-h ozone mixing ratio and the cut-off value set at 35 ppb (70 μg m–3) calculated for all days in a year. Annual summation ppb × days 
d) 3MMDA1 Annual maximum of the three-month average of daily 1-hour maximum ozone value. Three month running mean values calculated were assigned to the mid-point of the 3 month period. Annual ppb 
e) AVGMDA8 6-month warm season mean of MDA8. Warm season ppb 
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