How the new climate scenarios will affect air quality trends: An exploratory research.

In a changing climate, climate scenarios are an essential part of air quality research and assessment. The main goal of this work is to provide an exploratory analysis of the implications of CMIP6 scenarios on air quality, focused on the three high-priority scenarios of IPCC Sixth Assessment Report: SSP2–4.5, SSP3–7.0 and SSP5–8.5. In addition, the similarities and differences between the meteorological and air quality trends from CMIP5 and CMIP6 scenarios were assessed. For that, high-resolution simulations were conducted, having as case study mainland Portugal. The results revealed that it is not possible to establish a clear trend of greater/lesser severity between RCPs and SSPs analogous scenarios, with the similarities (and/or differences) depending on the climate variable and its location in space and time. In addition, due to the narratives that underlies SSPs it is not feasible to establish a direct link between climate and air quality impacts. This happens, since unlike RCPs, SSPs do not show a direct relationship between radiative forcing and the severity of climate impacts. Finally, SSP3–7.0 scenario imposes climate impacts close to those obtained by SSP5–8.5, promoting an overall increase of main air pollutants concentrations (comparing to a reference scenario). Further steps for the research community will involve regional numerical modelling across different areas for use in air quality studies, including a closer look at health implications. [Display omitted] • Comparison of CMIP5 (RCPs) and CMIP6 (SSPs) scenarios in an air quality perspective. • SSPs with higher radiative forcing, may not impose higher air quality impacts. • SSP3–7.0 scenario imposes climate impacts close to those obtained by SSP5–8.5. • SSP3–7.0 scenario can exacerbate the main air pollutants concentrations. • SSPs allow a complete view of the links between climate and air quality policies. [ABSTRACT FROM AUTHOR]