The impact of atmospheric blocking on the compounding effect of ozone pollution and temperature: a copula-based approach

Abstract

Abstract. Ozone pollution and high temperatures have adverse health impacts that can be amplified by the combined effects of ozone and temperature. Moreover, changes in weather patterns are expected to alter ozone pollution episodes and temperature extremes. In particular, atmospheric blocking is a high-impact, large-scale phenomenon at mid-high latitudes that has been associated with temperature extremes. This study examines the impact of atmospheric blocking on the ozone and temperature dependence among measurement stations over Europe during the period 1999–2015. We use a copula-based method to model the dependence between the two variables under blocking and non-blocking conditions. This approach allows us to examine the impact of blocks on the joint probability distribution. Our results showed that blocks lead to increasing strength in the upper tail dependence of ozone and temperature extremes (> 95th percentile) in north-west and central Europe (e.g. the UK, Belgium, Netherlands, Luxembourg, Germany and the north-west of France). The analysis of the probability hazard scenarios revealed that blocks generally enhance the probability of compound ozone and temperature events by 20 % in a large number of stations over central Europe. The probability of ozone or temperature exceedances increases 30 % (on average) under the presence of atmospheric blocking. Furthermore, we found that, in a number of stations over north-western Europe, atmospheric blocking increases the probability of ozone exceedances by 30 % given high temperatures. Our results point out the strong influence of atmospheric blocking on the compounding effect of ozone and temperature events, suggesting that blocks might be considered a relevant predicting factor when assessing the risks of ozone-heat-related health effects.

Attribution of surface ozone to NO<sub>x</sub> and VOC sources during two different high ozone events

“…As also shown in Otero et al (2022), over Germany during the period 1999-2015, atmospheric blocking leads to temperature anomalies > 5° C that induces MDA8 O3 anomalies >20 µg/m 3 . An occluded front on August 9, 2015, 290 led to reduced ozone values in West Germany, and it was followed by a warm front that affected North Germany, which explains the low ozone values observed/modeled in this region.…”

Influence of Synoptic Meteorology on Airborne Allergenic Pollen and Spores in an Urban Environment in Northeastern Iberian Peninsula

“…A.1). During atmospheric blocking situations, high pressure zones remain stationary for several days, giving rise to stagnation of air mass, accumulation of pollutants, including pollen and spores, and, eventually, causing serious air pollution situations (Otero et al, 2022). Platanus and Cupressaceae also showed both the highest daily mean concentration in SMP-1 and SMP-6 (Table 3).…”

Compound dry-hot-fire events in South America: an unapparent, long-range and deadly ripple effect

“…Conversely, the rapid improvement in air quality after PMP1 may be linked to a sudden decay of the blocking pattern followed by a return to transient waves and precipitation. Moreover, the co-occurrence of extremely hot weather and air pollution episodes is expected to amplify the impact on health beyond the sum of their effects individually 31,32 .…”