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Does toxicity of aromatic pollutants increase under remote atmospheric conditions?

Kroflič A, Grilc M, Grgić I - Sci Rep (2015)

Bottom Line: Aromatic compounds contribute significantly to the budget of atmospheric pollutants and represent considerable hazard to living organisms.Revising the recent understanding of atmospheric aqueous phase chemistry, which is mostly concerned with the radical nitration mechanisms, the observed phenomenon is mainly attributed to the electrophilic nitrogen-containing reactive species.Here, their intriguing role is closely inspected and discussed from the ecological perspective.

View Article: PubMed Central - PubMed

Affiliation: Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia.

ABSTRACT
Aromatic compounds contribute significantly to the budget of atmospheric pollutants and represent considerable hazard to living organisms. However, they are only rarely included into atmospheric models which deviate substantially from field measurements. A powerful experimental-simulation tool for the assessment of the impact of low- and semi-volatile aromatic pollutants on the environment due to their atmospheric aqueous phase aging has been developed and introduced for the first time. The case study herein reveals that remote biotopes might be the most damaged by wet urban guaiacol-containing biomass burning aerosols. It is shown that only after the primary pollutant guaiacol has been consumed, its probably most toxic nitroaromatic product is largely formed. Revising the recent understanding of atmospheric aqueous phase chemistry, which is mostly concerned with the radical nitration mechanisms, the observed phenomenon is mainly attributed to the electrophilic nitrogen-containing reactive species. Here, their intriguing role is closely inspected and discussed from the ecological perspective.

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Related in: MedlinePlus

Urban case simulation study.Consecutive evening BB events in the urban area with anthropogenic NOx emissions during the daytime. Concentration of GUA (solid dark blue line) in the simulation study was adjusted to 0.01 mM every 24 hours (in the simulated evening) and that of NaNO2 (dashed cyan line) was held constant at 0.1 mM through the daytime (for every second 12 hours). The concentration of H2O2 (dashed blue line) was held constant throughout the simulation study at 0.1 mM. Temperature and pH were assumed to be 25°C and 4.5, respectively. Other symbols used: 4NG (solid green line), 6NG (solid dark grey line), DNG (solid orange line), NO2· (solid dark cyan line), NO· (solid blue line), NO2+ (solid red line), and NO+ (solid dark yellow line).
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f1: Urban case simulation study.Consecutive evening BB events in the urban area with anthropogenic NOx emissions during the daytime. Concentration of GUA (solid dark blue line) in the simulation study was adjusted to 0.01 mM every 24 hours (in the simulated evening) and that of NaNO2 (dashed cyan line) was held constant at 0.1 mM through the daytime (for every second 12 hours). The concentration of H2O2 (dashed blue line) was held constant throughout the simulation study at 0.1 mM. Temperature and pH were assumed to be 25°C and 4.5, respectively. Other symbols used: 4NG (solid green line), 6NG (solid dark grey line), DNG (solid orange line), NO2· (solid dark cyan line), NO· (solid blue line), NO2+ (solid red line), and NO+ (solid dark yellow line).

Mentions: The proposed theoretical model of GUA aging in aqueous solution (Supplementary Fig. 1) was used to simulate its fate in deliquescent aerosols by mimicking the diurnal cycle and considering two distinct scenarios: i) consecutive evening BB events in an urban area with anthropogenic NOx emissions during the daytime (urban case) and ii) single evening BB event in an urban area with anthropogenic NOx emissions during the daytime, followed by migration of the formed deliquescent OA toward remote regions with no new emissions of either GUA or NOx (remote case). In both simulations starting with an evening BB event, kinetic constants valid at the applied experimental conditions were used (25°C, pH 4.5). For other simulation parameters (concentrations of GUA, NaNO2, and H2O2) please refer to Methods section. Results of the simulation study are shown in Figs. 1 and 2 for urban and remote atmospheric conditions, respectively.


Does toxicity of aromatic pollutants increase under remote atmospheric conditions?

Kroflič A, Grilc M, Grgić I - Sci Rep (2015)

Urban case simulation study.Consecutive evening BB events in the urban area with anthropogenic NOx emissions during the daytime. Concentration of GUA (solid dark blue line) in the simulation study was adjusted to 0.01 mM every 24 hours (in the simulated evening) and that of NaNO2 (dashed cyan line) was held constant at 0.1 mM through the daytime (for every second 12 hours). The concentration of H2O2 (dashed blue line) was held constant throughout the simulation study at 0.1 mM. Temperature and pH were assumed to be 25°C and 4.5, respectively. Other symbols used: 4NG (solid green line), 6NG (solid dark grey line), DNG (solid orange line), NO2· (solid dark cyan line), NO· (solid blue line), NO2+ (solid red line), and NO+ (solid dark yellow line).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4352892&req=5

f1: Urban case simulation study.Consecutive evening BB events in the urban area with anthropogenic NOx emissions during the daytime. Concentration of GUA (solid dark blue line) in the simulation study was adjusted to 0.01 mM every 24 hours (in the simulated evening) and that of NaNO2 (dashed cyan line) was held constant at 0.1 mM through the daytime (for every second 12 hours). The concentration of H2O2 (dashed blue line) was held constant throughout the simulation study at 0.1 mM. Temperature and pH were assumed to be 25°C and 4.5, respectively. Other symbols used: 4NG (solid green line), 6NG (solid dark grey line), DNG (solid orange line), NO2· (solid dark cyan line), NO· (solid blue line), NO2+ (solid red line), and NO+ (solid dark yellow line).
Mentions: The proposed theoretical model of GUA aging in aqueous solution (Supplementary Fig. 1) was used to simulate its fate in deliquescent aerosols by mimicking the diurnal cycle and considering two distinct scenarios: i) consecutive evening BB events in an urban area with anthropogenic NOx emissions during the daytime (urban case) and ii) single evening BB event in an urban area with anthropogenic NOx emissions during the daytime, followed by migration of the formed deliquescent OA toward remote regions with no new emissions of either GUA or NOx (remote case). In both simulations starting with an evening BB event, kinetic constants valid at the applied experimental conditions were used (25°C, pH 4.5). For other simulation parameters (concentrations of GUA, NaNO2, and H2O2) please refer to Methods section. Results of the simulation study are shown in Figs. 1 and 2 for urban and remote atmospheric conditions, respectively.

Bottom Line: Aromatic compounds contribute significantly to the budget of atmospheric pollutants and represent considerable hazard to living organisms.Revising the recent understanding of atmospheric aqueous phase chemistry, which is mostly concerned with the radical nitration mechanisms, the observed phenomenon is mainly attributed to the electrophilic nitrogen-containing reactive species.Here, their intriguing role is closely inspected and discussed from the ecological perspective.

View Article: PubMed Central - PubMed

Affiliation: Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia.

ABSTRACT
Aromatic compounds contribute significantly to the budget of atmospheric pollutants and represent considerable hazard to living organisms. However, they are only rarely included into atmospheric models which deviate substantially from field measurements. A powerful experimental-simulation tool for the assessment of the impact of low- and semi-volatile aromatic pollutants on the environment due to their atmospheric aqueous phase aging has been developed and introduced for the first time. The case study herein reveals that remote biotopes might be the most damaged by wet urban guaiacol-containing biomass burning aerosols. It is shown that only after the primary pollutant guaiacol has been consumed, its probably most toxic nitroaromatic product is largely formed. Revising the recent understanding of atmospheric aqueous phase chemistry, which is mostly concerned with the radical nitration mechanisms, the observed phenomenon is mainly attributed to the electrophilic nitrogen-containing reactive species. Here, their intriguing role is closely inspected and discussed from the ecological perspective.

Show MeSH
Related in: MedlinePlus