Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer

Abstract

Abstract. Ozone holds a certain fascination in atmospheric science. It is ubiquitous in the atmosphere, central to tropospheric oxidation chemistry, yet harmful to human and ecosystem health as well as being an important greenhouse gas. It is not emitted into the atmosphere but is a byproduct of the very oxidation chemistry it largely initiates. Much effort is focused on the reduction of surface levels of ozone owing to its health and vegetation impacts, but recent efforts to achieve reductions in exposure at a country scale have proved difficult to achieve owing to increases in background ozone at the zonal hemispheric scale. There is also a growing realisation that the role of ozone as a short-lived climate pollutant could be important in integrated air quality climate change mitigation. This review examines current understanding of the processes regulating tropospheric ozone at global to local scales from both measurements and models. It takes the view that knowledge across the scales is important for dealing with air quality and climate change in a synergistic manner. The review shows that there remain a number of clear challenges for ozone such as explaining surface trends, incorporating new chemical understanding, ozone-climate coupling, and a better assessment of impacts. There is a clear and present need to treat ozone across the range of scales, a transboundary issue, but with an emphasis on the hemispheric scales. New observational opportunities are offered both by satellites and small sensors that bridge the scales.

Halogen chemistry reduces tropospheric O<sub>3</sub> radiative forcing

“…Tropospheric chemistry is a highly coupled system with significant interplay between the NO x , HO x , and RO x systems (Monks et al, 2015). Changes in the individual production and loss terms are relatively small, but halogens reduce net O 3 production by 194 Tg yr −1 in the present day and 145 Tg yr −1 in the preindustrial.…”

Reanalysis of and attribution to near-surface ozone concentrations in Sweden during 1990–2013

“…Although the stratospheric contribution to the O 3 concentrations at the surface is generally small (3-5 ppb(v)) in Europe (Lelieveld and Dentener, 2000), it can be a relevant contribution to near-surface O 3 in certain areas and time periods (Zanis et al, 2014) and could affect the observed trend in near-surface O 3 (e.g., Fusco and Logan, 2003). Despite the large number of studies of tropospheric O 3 , a number of challenges still remain, such as explaining the near-surface concentration trends (Monks et al, 2015).…”

“…Asian emissions have continued to rise under the same period (Ohara et al, 2007). Jonson et al (2006) showed that the trend in O 3 concentrations in Europe cannot be fully explained by changes in European precursor emissions.…”

High-resolution inversion of OMI formaldehyde columns to quantify isoprene emission on ecosystem-relevant scales: application to the Southeast US

“…Isoprene oxidation fuels tropospheric ozone formation in both rural and urban regions (Monks et al, 2015), and isoprene oxidation products contribute significantly to organic aerosol (Carlton et al, 2009). Regional air-quality predictions are heavily dependent on isoprene emission estimates (Pierce et al, 1998;Fiore et al, 2005;Hogrefe et al, 2011;Mao et al, 2013).…”