Table 1

Summary of the metrics relevant for model-measurement comparison (Section 2.3.1), characterization of free tropospheric ozone (Section 2.3.2), human health impacts (Section 2.3.3), and vegetation impacts (Section 2.3.4). DOI: https://doi.org/10.1525/elementa.279.t1

MetricUnitsApplication AreaExample Reference(s)

Monthly mean of the 24-h average values ppb Model-measurement comparison metrics Young et al. (2018) and references therein
Monthly standard deviation, median, 5th, 25th, 75th, and 95th percentiles of the maximum daily average 8-h (MDA8) ozone values ppb Model-measurement comparison metrics Fiore et al. (2014); Dolwick et al. (2015)
Monthly mean diurnal cycle (monthly average of 1-h ozone averages at 0100 h, 0200 h, 0300 h, etc.) ppb Model-measurement comparison metrics Schnell et al. (2015)
Monthly mean of daily minimum and maximum hourly average ozone values ppb Model-measurement comparison metrics Schnell et al. (2015)
Monthly, seasonal, annual and decadal means from ozonesonde, aircraft, and lidar measurements on pressure surfaces at intervals of 25 hPa from 1000 hPa to the tropopause. Standard deviations, median and 5th, 25th, 75th, and 95th percentiles are provided where sampling is sufficient. ppb Free tropospheric metrics Young et al. (2018) and references therein
Monthly mean diurnal cycle at hourly intervals with high frequency aircraft data (MOZAIC-IAGOS), and also lidar where data frequency permits. ppb Free tropospheric metrics Young et al. (2018) and references therein
Monthly mean tropospheric column ozone (TCO) from satellite instruments Dobson Units Free tropospheric metrics Young et al. (2018) and references therein
Monthly mean (Total Column Ozone (TCO) from ozonesondes Dobson Units Free tropospheric metrics Young et al. (2018) and references therein
Estimates of the annual cycle, at monthly intervals, averaged over each decade on 25 hPa pressure surfaces or for TCO ppb/Dobson Units Free tropospheric metrics Young et al. (2018) and references therein
The 4th highest MDA8 ozone value over the entire year (see text for specific calculation protocols). ppb Human health US Federal Register (2015)
Maximum daily 8-h average over the entire year ppb Human health European Council Directive 2008/50/EC; WHO (2006); Kamyotra et al. (2012); SANS (2011); Qiao et al. (2015)
Maximum daily 1-h average ozone value over the entire year. ppb Human health European Council Directive 2008/50/EC; Kamyotra et al. (2012); Qiao et al. (2015)
4th highest W90 5-h cumulative exposure index ppb-hrs Human health Lefohn et al. (2010b)
SOMO35: Annual sum of the positive differences between the daily maximum 8-h average ozone value and the cutoff value set at 35 ppb ppb-day Human health Amann et al. (2008); REVIHAAP (2013)
SOMO10: Annual sum of the positive differences between the daily maximum 8-h average ozone value and the cutoff value set at 10 ppb ppb-day Human health REVIHAAP (2013)
Number of exceedances of daily maximum 1-h average values greater than 90, 100, and 120 ppb per year number of hours Human health Qiao et al. (2015)
Number of exceedances of daily maximum 8-h average values greater than 50, 60, 70, and 80 ppb per year number of hours Human health US Federal Register (2015); WHO (2006); European Council Directive 2008/50/EC
Running mean of the 3-month average of the daily 1-h maximum ozone value ppb Human health Brauer et al. (2016)
Annual and summertime mean of the daily maximum 8-h average values ppb Human health Turner et al. (2016)
Annual and seasonal percentiles (median, 5th, 25th, 75th and 95th) of all hourly average values. ppb Human health Xu et al. (2008); Simon et al. (2015)
W126 for various months and daily time periods (see text) ppb-hrs Vegetation Lefohn et al. (1988)
AOT40 for various months and daily time periods (see text) ppb h Vegetation CLRTAP (2017)
Daily 12-h average for various months and daily time periods (see text) ppb Vegetation Heck et al. (1988); Jäger et al. (1992); Legge et al. (1995)
Seasonal percentiles (median, 5th, 25th, 75th, 95th, 98th, and 99th) of hourly average ozone values ppb Vegetation Xu et al. (2008)
Flux-Based Indices nmol m–2 Projected Leaf Area s–1 Vegetation Emberson et al. (2000); Mills et al. (2011b)
MetricUnitsApplication AreaExample Reference(s)

Monthly mean of the 24-h average values ppb Model-measurement comparison metrics Young et al. (2018) and references therein
Monthly standard deviation, median, 5th, 25th, 75th, and 95th percentiles of the maximum daily average 8-h (MDA8) ozone values ppb Model-measurement comparison metrics Fiore et al. (2014); Dolwick et al. (2015)
Monthly mean diurnal cycle (monthly average of 1-h ozone averages at 0100 h, 0200 h, 0300 h, etc.) ppb Model-measurement comparison metrics Schnell et al. (2015)
Monthly mean of daily minimum and maximum hourly average ozone values ppb Model-measurement comparison metrics Schnell et al. (2015)
Monthly, seasonal, annual and decadal means from ozonesonde, aircraft, and lidar measurements on pressure surfaces at intervals of 25 hPa from 1000 hPa to the tropopause. Standard deviations, median and 5th, 25th, 75th, and 95th percentiles are provided where sampling is sufficient. ppb Free tropospheric metrics Young et al. (2018) and references therein
Monthly mean diurnal cycle at hourly intervals with high frequency aircraft data (MOZAIC-IAGOS), and also lidar where data frequency permits. ppb Free tropospheric metrics Young et al. (2018) and references therein
Monthly mean tropospheric column ozone (TCO) from satellite instruments Dobson Units Free tropospheric metrics Young et al. (2018) and references therein
Monthly mean (Total Column Ozone (TCO) from ozonesondes Dobson Units Free tropospheric metrics Young et al. (2018) and references therein
Estimates of the annual cycle, at monthly intervals, averaged over each decade on 25 hPa pressure surfaces or for TCO ppb/Dobson Units Free tropospheric metrics Young et al. (2018) and references therein
The 4th highest MDA8 ozone value over the entire year (see text for specific calculation protocols). ppb Human health US Federal Register (2015)
Maximum daily 8-h average over the entire year ppb Human health European Council Directive 2008/50/EC; WHO (2006); Kamyotra et al. (2012); SANS (2011); Qiao et al. (2015)
Maximum daily 1-h average ozone value over the entire year. ppb Human health European Council Directive 2008/50/EC; Kamyotra et al. (2012); Qiao et al. (2015)
4th highest W90 5-h cumulative exposure index ppb-hrs Human health Lefohn et al. (2010b)
SOMO35: Annual sum of the positive differences between the daily maximum 8-h average ozone value and the cutoff value set at 35 ppb ppb-day Human health Amann et al. (2008); REVIHAAP (2013)
SOMO10: Annual sum of the positive differences between the daily maximum 8-h average ozone value and the cutoff value set at 10 ppb ppb-day Human health REVIHAAP (2013)
Number of exceedances of daily maximum 1-h average values greater than 90, 100, and 120 ppb per year number of hours Human health Qiao et al. (2015)
Number of exceedances of daily maximum 8-h average values greater than 50, 60, 70, and 80 ppb per year number of hours Human health US Federal Register (2015); WHO (2006); European Council Directive 2008/50/EC
Running mean of the 3-month average of the daily 1-h maximum ozone value ppb Human health Brauer et al. (2016)
Annual and summertime mean of the daily maximum 8-h average values ppb Human health Turner et al. (2016)
Annual and seasonal percentiles (median, 5th, 25th, 75th and 95th) of all hourly average values. ppb Human health Xu et al. (2008); Simon et al. (2015)
W126 for various months and daily time periods (see text) ppb-hrs Vegetation Lefohn et al. (1988)
AOT40 for various months and daily time periods (see text) ppb h Vegetation CLRTAP (2017)
Daily 12-h average for various months and daily time periods (see text) ppb Vegetation Heck et al. (1988); Jäger et al. (1992); Legge et al. (1995)
Seasonal percentiles (median, 5th, 25th, 75th, 95th, 98th, and 99th) of hourly average ozone values ppb Vegetation Xu et al. (2008)
Flux-Based Indices nmol m–2 Projected Leaf Area s–1 Vegetation Emberson et al. (2000); Mills et al. (2011b)
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