2000–2014 trends of global daytime average ozone (nmol mol^–1 yr^–1). 2000–2014 trends of daytime average ozone (nmol mol^–1 yr^–1) at 1375 non-urban sites in December–January–February (top) and 1784 non-urban sites in June–July–August (bottom). The number of available sites is greater in June–July–August because many US sites only operate in the warm season. Vector colors indicate the p-values on the linear trend for each site: blues indicate negative trends, oranges indicate positive trends and green indicates weak or no trend; lower p-values have greater color saturation. DOI: https://doi.org/10.1525/elementa.291.f13