Phenomenology of summer ozone episodes over the Madrid Metropolitan Area, central Spain

Abstract

Various studies have reported that the photochemical nucleation of new ultrafine particles (UFPs) in urban environments within high insolation regions occurs simultaneously with high ground ozone (O 3 ) levels. In this work, we evaluate the atmospheric dynamics leading to summer O 3 episodes in the Madrid air basin (central Iberia) by means of measuring a 3-D distribution of concentrations for both pollutants. To this end, we obtained vertical profiles (up to 1200 m above ground level) using tethered balloons and miniaturised instrumentation at a suburban site located to the SW of the Madrid Metropolitan Area (MMA), the Majada-honda site (MJDH), in July 2016. Simultaneously, measurements of an extensive number of air quality and meteorological parameters were carried out at three supersites across the MMA. Furthermore, data from O 3 soundings and daily radio soundings were also used to interpret atmospheric dynamics.The results demonstrate the concatenation of venting and accumulation episodes, with relative lows (venting) and peaks (accumulation) in O 3 surface levels. Regardless of the episode type, the fumigation of high-altitude O 3 (arising from a variety of origins) contributes the major proportion of surface O 3 concentrations. Accumulation episodes Published by Copernicus Publications on behalf of the European Geosciences Union.

Source attribution of European surface O<sub>3</sub> using a tagged O<sub>3</sub> mechanism

“…Local sources can contribute to more than 20 % of the mean MDA8 O 3 mixing ratio (from 14.6 % in SCA to 35.7 % in the Po Valley; see Table S1). This shows that local sources play a strong role in the formation of O 3 throughout the June-August period, as has been previously shown by Jiménez et al (2006) and Querol et al (2018). Compared with late spring, the relative contribution of overseas sources decreased in summer, varying from 10.9 % in the Po Valley receptor region to 44.8 % in the UKI region in the month of July (Figs.…”

“…2-4). Several studies, such as Safieddine et al (2014), Tagaris et al (2017), Mertens et al (2018), Querol et al (2018) African shore and it exhibits a zonal pattern, with low mixing ratios occurring in the north and high mixing ratios occurring south of the Mediterranean Sea, a trend mostly due to O 3 mixing ratios from NAF and RST sources.…”

“…It also affects the radiative forcing (e.g. Ramaswamy et al, 2001;Stevenson et al, 2013) and therefore contributes to climate change. Impacts of O 3 on human health are associated with lung disease, chronic disease, and death from respiratory ailments.…”

Analysis of summer O<sub>3</sub> in the Madrid air basin with the LOTOS-EUROS chemical transport model

“…15 Figure 13a presents a comparison between observed (data from Querol et al (2018)) and simulated (WRF_70 configuration) BLH at 12 UTC. We can observe that the model tends to overestimate the BLH at midday although the general trends are captured.…”

“…especially in the Mediterranean region where the atmospheric dynamics in summer is characterised by complex recirculation processes with effective vertical exchange (Millán et al, 1997(Millán et al, , 2000Gangoiti et al, 2001;Borge et al, 2010;Querol et al, 2017Querol et al, , 2018. The lack of an appropriate representation of the vertical variability of O 3 has been recognised as one of the shortcomings of the CTMs and in consequence a major challenge in the future development of the models (Hess and Zbinden, 2013;Monks et al, 2015).…”