Global distribution and trends of tropospheric ozone: An observation-based review

Abstract

Tropospheric ozone plays a major role in Earth's atmospheric chemistry processes and also acts as an air pollutant and greenhouse gas. Due to its short lifetime, and dependence on sunlight and precursor emissions from natural and anthropogenic sources, tropospheric ozone's abundance is highly variable in space and time on seasonal, interannual and decadal time-scales. Recent, and sometimes rapid, changes in observed ozone mixing ratios and ozone precursor emissions inspired us to produce this up-to-date overview of tropospheric ozone's global distribution and trends. Much of the text is a synthesis of in situ and remotely sensed ozone observations reported in the peer-reviewed literature, but we also include some new and extended analyses using well-known and referenced datasets to draw connections between ozone trends and distributions in different regions of the world. In addition, we provide a brief evaluation of the accuracy of rural or remote surface ozone trends calculated by three state-of-the-science chemistry-climate models, the tools used by scientists to fill the gaps in our knowledge of global tropospheric ozone distribution and trends.

On instrumental errors and related correction strategies of ozonesondes: possible effect on calculated ozone trends for the nearby sites Uccle and De Bilt

“…At the surface, ozone is an air pollutant that adversely impacts human health, natural vegetation, and crop yield and quality (e.g. Cooper et al, 2014).…”

“…Thereafter, a levelling off of the ozone amounts took place due to declining anthropogenic ozone precursor emissions (e.g. Cooper et al, 2014).…”

Tropical tropospheric ozone columns from nadir retrievals of GOME-1/ERS-2, SCIAMACHY/Envisat, and GOME-2/MetOp-A (1996–2012)

“…In the UT, ozone is an important greenhouse gas with an estimated global-averaged radiative forcing of 0.40±0.20 W m −2 (Stevenson et al, 2013;IPCC, 2013), and it contributes greatly to the oxidation efficiency of the atmosphere. Ozone is the primary tropospheric source of hydroxyl (OH) and peroxy (RO x ) radicals, which affect the lifetime of other greenhouse gases such as methane CH 4 (Crutzen, 1974;Shindell et al, 2009;Cooper et al, 2014). In the lower troposphere, close to the ground, ozone can be extremely harmful for human health as it can oxidise biological tissues and causes respiratory problems.…”

“…The global-averaged tropospheric ozone lifetime is 22±2 days (Stevenson et al, 2006). In contrast, ozone's lifetime in the boundary layer is much shorter (a few hours) because it is more likely to be destroyed by surface deposition and chemical reactions, whereas in the middle and UT its lifetime is on the order of weeks to months (Cooper et al, 2014). There are several ways that convection impacts on tropospheric ozone and its precursors.…”

“…Nevertheless, world population growth and industrialisation have led to a strong increase in anthropogenic emissions, resulting in an increase in the tropospheric ozone burden (300 ± 30 Tg; IPCC, 2007) by 1-7 % per decade in the tropics (Beig and Singh, 2007;Cooper et al, 2014). Undoubtedly, the need to control the tropospheric ozone increase is crucial.…”