Changes of daily surface ozone maxima in Switzerland in all seasons from 1992 to 2002 and discussion of summer 2003

Abstract

Abstract. An Analysis of Covariance (ANCOVA) was used to derive the influence of the meteorological variability on the daily maximum ozone concentrations at 12 low-elevation sites north of the Alps in Switzerland during the four seasons in the 1992-2002 period. The afternoon temperature and the morning global radiation were the variables that accounted for most of the meteorological variability in summer and spring, while other variables that can be related to vertical mixing and dilution of primary pollutants (afternoon global radiation, wind speed, stability or day of the week) were more significant in winter. In addition, the number of days after a frontal passage was important to account for ozone build-up in summer and ozone destruction in winter. The statistical model proved to be a robust tool for reducing the impact of the meteorological variability on the ozone concentrations. The explained variance of the model, averaged over all stations, ranged from 60.2% in winter to 71.9% in autumn. The year-to-year variability of the seasonal medians of daily ozone maxima was reduced by 85% in winter, 60% in summer, and 50% in autumn and spring after the meteorological adjustment. For most stations, no significantly negative trends (at the 95% confidence level) of the summer medians of daily O 3 or O x (O 3 +NO 2 ) maxima were found despite the significant reduction in the precursor emissions in Central Europe. However, significant downward trends in the summer 90th percentiles of daily O x maxima were observed at 6 sites in the region around Zürich (on average −0.73 ppb yr −1 for those sites). The lower effect of the titration by NO as a consequence of the reduced emissions could partially explain the significantly positive O 3 trends in the cold seasons (on average 0.69 ppb yr −1 in winter and 0.58 ppb yr −1 in autumn). The increase of O x found for most stations in autumn (on average 0.23 ppb yr −1 ) and winter (on average 0.39 ppb yr −1 ) could be due to increasing European background ozone levCorrespondence to: A. S. H. Prévôt (andre.prevot@psi.ch) els, in agreement with other studies. The statistical model was also able to explain the very high ozone concentrations in summer 2003, the warmest summer in Switzerland for at least ∼150 years. On average, the measured daily ozone maximum was 15 ppb (nearly 29%) higher than in the reference period summer 1992-2002, corresponding to an excess of 5 standard deviations of the summer means of daily ozone maxima in that period.

The toxicology of climate change: Environmental contaminants in a warming world

“…Qian et al (2008) found a synergistic effect of PM 10 and high temperatures on daily cardio-respiratory (Bell et al, 2007;Confalonieri et al, 2007;Dominici et al, 2006;Fiala et al, 2003;IPCC, 2007a;Katsouyanni et al, 1993;Knowlton et al, 2004;Koken et al, 2003;Mauzerall et al, 2005;Ordonez et al, 2005;Rainham and Smoyer-Tomic, 2003;Ren and Tong, 2006) ▪ The elderly and individuals with pre-existing cardio-respiratory disease may be more vulnerable to these effects Altered exposure and risk ▪ Some populations may experience increases or decreases in POP exposures and health risks depending on the region and diet of exposed individuals (Bard, 1999;Gordon, 1997;McKone et al, 1996;Watkinson et al, 2003) ▪ Pesticides may impair mechanisms of temperature regulation especially during times of thermal stress Increased susceptibility to pathogens ▪ Toxicants can suppress immune function, and climate-induced shifts in disease vector range will result in novel pathogen exposure (Abadin et al, 2007;Haines et al, 2006;Lipp et al, 2002;Nagayama et al, 2007;Patz et al, 2005;Rogers and Randolph, 2000;Smialowicz et al, 2001) ▪ Immune system impairment linked to toxicants may increase human vulnerability to climate shifts in pathogens ▪ Low-income populations, infants, children, and the chronically ill may be more susceptible exposures may sensitize individuals to allergic disease ▪ Low-income populations, infants, children, and the chronically ill may be more susceptible mortality in Wuhan, China. The PM 10 effects were strongest on extremely high temperature days (daily average temperature 33.1°C) and weakest during normal temperature days (daily average temperature 18°C).…”

“…However, a number of studies suggest that the toxicity of ozone and PM will be exacerbated with global warming, and some of these data support that older adults will be especially vulnerable (Bell et al, 2007;Confalonieri et al, 2007;Dominici et al, 2006;Fiala et al, 2003;IPCC, 2007c;Katsouyanni et al, 1993;Knowlton et al, 2004;Koken et al, 2003;Mauzerall et al, 2005;Ordonez et al, 2005;Rainham and Smoyer-Tomic, 2003;Ren and Tong, 2006). Other potential interactions between climate change and toxicant exposure include increased susceptibility to pathogens (Abadin et al, 2007;Nagayama et al, 2007;Smialowicz et al, 2001) and aeroallergens (D'Amato et al, 2002;Diaz-Sanchez et al, 2003;Epstein, 2005;Janssen et al, 2003).…”

“…Ebi et al (2006) note that there will be 100 million more Americans that are aged 65 or older in 2100 than in 2000, leading to generally increased vulnerability of the U.S. population to climate sensitive health outcomes. The effects of contaminants on vulnerable subpopulations warrant further study, although there is evidence that older individuals will be more susceptible to climate-air pollutant interactions (Fiala et al, 2003;Koken et al, 2003;Ordonez et al, 2005). In addition, low-income populations, infants, children, and chronically ill individuals may be especially susceptible to climate sensitive outcomes linked to interactions between pollutant exposures and changes in vector-borne and allergic disease (D'Amato et al, 2002;Diaz-Sanchez et al, 2003;Epstein, 2005;Haines et al, 2006;Janssen et al, 2003).…”

“…Epidemiological evidence suggests that heat exacerbates mortality and morbidity from cardio-respiratory disease in humans exposed to ozone and PM (Fiala et al, 2003;IPCC, 2007c;Koken et al, 2003;Ordonez et al, 2005;Rainham and Smoyer-Tomic, 2003). During the European heat wave of 2003, there was a surge in respiratory illnesses that was associated with increased concentrations of particulates and ozone especially among the elderly (Fiala et al, 2003;Ordonez et al, 2005).…”

“…Epidemiological evidence suggests that heat exacerbates mortality and morbidity from cardio-respiratory disease in humans exposed to ozone and PM (Fiala et al, 2003;IPCC, 2007c;Koken et al, 2003;Ordonez et al, 2005;Rainham and Smoyer-Tomic, 2003). During the European heat wave of 2003, there was a surge in respiratory illnesses that was associated with increased concentrations of particulates and ozone especially among the elderly (Fiala et al, 2003;Ordonez et al, 2005). In another study illustrating the effects of climate sensitive outcomes on vulnerable older populations, males in Denver, Colorado aged 65 and older were found to be at increased risk for hospitalization for acute myocardial infarction, coronary arteriosclerosis, and pulmonary heart disease when co-exposed to higher temperatures and ozone (Koken et al, 2003).…”