Gaseous (DMS, MSA, SO<sub>2</sub>, H<sub>2</sub>SO<sub>4</sub> and DMSO) and particulate (sulfate and methanesulfonate) sulfur species over the northeastern coast of Crete

Abstract

Abstract.A detailed study of the levels, the temporal and diurnal variability of the main compounds involved in the biogenic sulfur cycle was carried out in Crete (Eastern Mediterranean) Dimethylsulfide (DMS) levels ranged from 2.9 to 136 pmol·mol −1 (mean value of 21.7 pmol·mol −1 ) and showed a clear diurnal variation with daytime maximum. During nighttime DMS levels fall close or below the detection limit of 2 pmol·mol −1 . Concurrent measurements of OH and NO 3 radicals during the campaign indicate that NO 3 levels can explain most of the observed diurnal variation of DMS. Dimethylsulfoxide (DMSO) ranged between 0.02 and 10.1 pmol·mol −1 (mean value of 1.7 pmol·mol −1 ) and presents a diurnal variation similar to that of DMS. SO 2 levels ranged from 220 to 2970 pmol·mol −1 (mean value of 1030 pmol·mol −1 ), while nss-SO 2− 4 and MS − ranged from 330 to 7100 pmol·mol −1 , (mean value of 1440 pmol·mol −1 ) and 1.1 to 37.5 pmol·mol −1 (mean value of 11.5 pmol·mol −1 ) respectively.Of particular interest are the measurements of gaseous MSA and H 2 SO 4 . MSA ranged from below the detection limit (3×10 4 ) to 3.7×10 7 molecules cm −3 , whereas H 2 SO 4 ranged between 1×10 5 and 9.0×10 7 molecules cm −3 . TheCorrespondence to: N. Mihalopoulos (Mihalo@chemistry.uoc.gr) measured H 2 SO 4 maxima are among the highest reported in literature and can be attributed to high insolation, absence of precipitation and increased SO 2 levels in the area. From the concurrent SO 2 , OH, and H 2 SO 4 measurements a sticking coefficient of 0.52±0.28 was calculated for H 2 SO 4 . From the concurrent MSA, OH, and DMS measurements the yield of gaseous MSA from the OH-initiated oxidation of DMS was calculated to range between 0.1-0.4%. This low MSA yield implies that gaseous MSA levels can not account for the observed MS − levels. Heterogeneous reactions of DMSO on aerosols should be considered to explain the observed levels of MS − .

Particle formation in the Arctic free troposphere during the ASTAR 2004 campaign: a case study on the influence of vertical motion on the binary homogeneous nucleation of H<sub>2</sub>SO<sub>4</sub>/H<sub>2</sub>O

“…A H 2 SO 4 mixing ratio of 80 pptv seems to be too high for all trajectories since no data points are found in the gray shaded area. This is in agreement with measurements of gaseous H 2 SO 4 which even in polluted areas showed mixing ratios lower than 80 pptv (Bardouki et al, 2003;Berresheim et al, 2002). A better comparison with the measurements can be derived when only the trajectories that were started near the location where the flights were performed are considered (Fig.…”

“…Gas phase sulfuric acid concentrations are typically much lower and range between 10 5 to 10 7 molecules cm −3 in clean air (e.g. Eisele and Tanner, 1993) and up to 10 8 molecules cm −3 for polluted air (Berresheim et al, 2002;Bardouki et al, 2003). The simulations were performed along the 36 trajectories for three different gas phase sulfuric acid mixing ratios µ H 2 SO 4 =1, 40 and 80 pptv (1 pptv=2.67×10 7 molecules cm −3 at 0 • C and 1013 hPa), where a mixing ratio of µ H 2 SO 4 =1 pptv is representative for clean air and mixing ratios of µ H 2 SO 4 =40 and 80 pptv are representative for polluted air.…”

Particulate pollutants in the Brazilian city of São Paulo: 1-year investigation for the chemical composition and source apportionment

“…In turn, As, Cd and Pb, identified as elements that can cause carcinogenic health effects (Behera et al, 2015), were also found predominantly in the PM 2.5 (over 75 %). In this way, they may be indicative of higher carcinogenicity of fine over coarse particles.…”

“…It is noteworthy that MSA was associated with NW winds. This species is often associated with the decomposition of DMS emitted by the sea (Bardouki et al, 2003). More studies are needed in order to identify MSA sources at this site.…”

Atmospheric new particle formation as a source of CCN in the eastern Mediterranean marine boundary layer

“…In general, sulfate concentrations started to increase very rapidly around noon and reached their diurnal maximum during the afternoon, after which they decreased first gradually and then more rapidly until the following noon. The afternoon increase in the sulfate concentration can be ascribed to the intensive photochemical production of gaseous sulfuric acid from both natural and anthropogenic precursors during daytime, followed by the condensation of sulfuric acid into preexisting aerosol particles together with gaseous ammonia (e.g., Zerefos et al, 2000;Kouvarakis and Mihalopoulos, 2002;Bardouki et al, 2003;Mihalopoulos et al, 2007). Since sulfate is practically non-volatile, the decreasing sulfate concentrations during night and morning hours are most likely a combination of air mass dilution by entrainment and aerosol deposition processes.…”