Case studies on summertime measurements of O3, NO2, and SO2 with a DOAS system in an urban semi-industrial region in Athens, Greece

Abstract

The objective of this study is to analyze the concentrations of SO2, NO2, and O3 measured by a Differential Optical Absorption Spectroscopy (DOAS) system that was operating at the campus of Technological Education Institute of Piraeus during 2008 and 2009 warm periods (July to September) in relation to the prevailing meteorological conditions. The DOAS system was operating in a particularly polluted area of the West part of Attica basin on a continuous basis, measuring the concentration levels of the main pollutants (O3, NO2, and SO2) as well as aromatic hydrocarbon substances (benzene, toluene, and xylene). According to the analysis, the SO2 concentration levels at this measuring site are rather high and this may be attributed to the characteristics of this measuring site. Proximity of roadways and local circulation are just some of the factors that can affect the concentration levels of monitoring of pollutant concentrations such as NO2 and surface ozone. The results provide evidence for the occurrence of an atmospheric phenomenon that produces higher ozone concentrations during weekends despite lower concentrations of ozone precursors. This phenomenon is known as the weekend effect.

Retrieval of near-surface sulfur dioxide (SO<sub>2</sub>) concentrations at a global scale using IASI satellite observations

“…During the day, the photochemistry is more active and the concentrations of oxidants such as OH, H 2 O 2 and O 3 are high, creating an important sink for SO 2 , which disappears at night, favourizing higher concentrations. Such a diurnal cycle of SO 2 has been observed previously in China (Wang, 2002;Wang et al, 2014) and in other regions of the world (Khemani et al, 1987;Psiloglou et al, 2013), but in others, noontime SO 2 peaks have also been observed (e.g. Lin et al, 2012;Xu et al, 2014), possibly as a result of other meteorological/dynamical effects (Xu et al, 2014).…”

“…3.4.1. Columns of 1 to 4 DU are measured above the smelters of Sar Cheshmeh copper complex (Rastmanesh et al, 2010(Rastmanesh et al, , 2011. Emissions of oil industries located on the Khark Island (Ardestani and Shafie-Pour, 2009;Fioletov et al, 2013) are also observed, with columns around 1 to 2 DU.…”

SO<sub>2</sub> noontime-peak phenomenon in the North China Plain

“…The SO 2 diurnal variation pattern observed in both the Yangtze River delta region (Wang et al, 2002;Qi et al, 2012) and the Pearl River delta region , as well as that observed in other parts of the world (Khemani et al, 1987;Psiloglou et al, 2013) seem to mostly comply to this rule, with a few exceptions found by Qi et al (2012).…”

The impacts of precursor reduction and meteorology on ground-level ozone in the Greater Toronto Area

“…Previous studies have provided evidence of a correlation existing between ozone levels and meteorological conditions, such as wind direction and speed, temperature and relative humidity (Agudelo-Castaneda et al, 2013;Figueiredo et al, 2013;Pekey and Ozaslan, 2013;Psiloglou et al, 2013). Specifically, Jacob et al (1993) discuss the significant dependence of O 3 concentrations on temperature, indicating that, at higher temperatures, local O 3 production is maximized as a result of the suppression of radicals being stored as peroxyacetylnitrate (PAN).…”

“…However, the production rate of ozone depends on precursor concentrations in a non-linear fashion. Previous studies of O 3 concentrations have indicated considerable variability from day to day and from year to year, not only as a result of changes in precursor emissions, but also of meteorology (AgudeloCastaneda et al, 2013;Figueiredo et al, 2013;Jacob et al, 1993;Pekey and Ozaslan, 2013;Psiloglou et al, 2013). Empirical and model studies have shown very strong positive correlations between O 3 production and temperature, and weaker correlations of ozone accumulation with wind speed and direction, pressure, cloud cover and humidity (BaertschRitter et al, 2004;Camalier et al, 2007;Dawson et al, 2007;Jacob et al, 1993).…”