Percentage of monitored population exposed to MDA8 > 60 ppb for more than 25 days per year. Percentage of monitored population (i.e. population within a 5 km radius of an ozone monitoring station) in urban and non-urban areas in a) individual countries in Europe, b) individual states in the US. Maps in the left column in % show reconstructed 2000 values calculated by subtracting the 2000–2014 trend from the 2010–2014 (present day) averages; maps in the middle column in % show present day (2010–2014 averages); maps in the right column show the difference (12 years) between the 2 periods. The scale on the difference plot is % change over 12 years (i.e. 2010–2014 average –2000). States and countries in grey have no data. Although whole EU countries/US states are coloured, this result applies only to locations within 5 km radius of ozone monitoring locations. DOI: https://doi.org/10.1525/elementa.273.f7