Laboratory research on aqueous reactions of isoprene with inorganic radicals Inna Kuznietsova Lech Gmachowski, Krzysztof J. Rudzinski Insitute of Physical Chemistry Polish Academy of Sciences Polish Academy of Sciences

2 Why ? interaction and transformation of atmospheric trace compounds interaction and transformation of atmospheric trace compounds formation of secondary organic aerosols formation of secondary organic aerosols(SOA)

3 SO 2 anthropogenic sources (80 TgS/year) anthropogenic sources (80 TgS/year) combustion of fossil fuels vehicles, aircraft, ships, power stations, industrial boilers industry ores smelting, scrubbing natural gas ores smelting, scrubbing natural gas natural sources (12 TgS/year) natural sources (12 TgS/year) volcanic eruptions oxidation of organic materials in soils atmospheric oxidation of dimethylsulfide rainforests

4 Autooxidation of S IV Mn(III) + SO 3 2- /HSO 3 - Mn(II) + SO 3  - Mn(II)Mn(III) S IV, O 2 2 SO 3 2- /2 HSO O 2 2 SO 4 2- /2 HSO 4 2- SO 3 -,SO 4 -, SO 5 - SO 3 2- / HSO 3 - SO 3 2- / HSO 3 - SO 2 + H 2 O

5 Isoprene Sources: Plants Plants Sea phytoplankton Sea phytoplankton Microbes Microbes Animals and humans Animals and humans Biomass burning Biomass burning Combustion and evaporation of fuels Combustion and evaporation of fuels Cigarette smoking Cigarette smoking Chemical technology Chemical technology (2-methyl-1,3-butadien)

6 Importance of isoprene Importance of isoprene Emission 500 TgC/year Emission 500 TgC/year High reactivity (OH, NO 3, O 3 ) High reactivity (OH, NO 3, O 3 ) Precursor of Secondary Organic Aerosols Precursor of Secondary Organic Aerosols Influence on formation photochemical smog Influence on formation photochemical smog Influence on autooxidation S IV Influence on autooxidation S IV

7 Gas-phase transformations of isoprene R, O 3 R OH NO 3 NO 3 NO Cl SO 3 SO 3 (....)

8 Typical gas-phase products aldehydesketones 3-methyl furan diolshydroxynitratesdinitratesperoxynitrates peroxyacetyl nitrates (PAN) methacrolyl nitrate (MPAN)

9 Heterogeneous and aqueous-phase transformations of isoprene hydroxyacetons2-methyltetraols hydroxycarboxyl acids dicarboxy acids sulfate-nitrate esters sulfate esters nitrate esters keto acids

10 25 o C pH = 4.5÷8.6 Na 2 SO 3 + Na 2 S 2 O 5 + O 2 Isoprene MnSO 4 UV [O 2 ],pH [iso], [S(IV)] ESI-MS(offline) Experimental setup

11 Wavelength, nm Recorded UV spectra of a reacting solution Absorbance, a.u. Initial concentrations, mM: MnSO 4 S IV C 5 H 8 O 2 pH Time, substrates Time, products

12 Changes of O 2 concentration and pH

13 Decreasing of S IV and isoprene with time

14 Identification of products Mass / charge Intensity, cps

15 Structures of the products

16 Reaction of isoprene with SO 4 -

17 Influence of isoprene on autooxidation of S IV in solution of different acidity in solution of different acidity experiments without isoprene (blue) and with isoprene (red) 2SO 3 2- /2HSO O 2 2SO 4 2- /2HSO 4 2- Rudziński et.al.2007 Proc. 6th Conf. Urban Air Quality, Cyprus

18Take-Home-Messages Aqueous-phase reactions of isoprene with sulfoxy radicals can be a source of atmospheric organosulfates and organosulfites Aqueous-phase reactions of isoprene with sulfoxy radicals can be a source of atmospheric organosulfates and organosulfites Influence of isoprene on aciditification of atmospheric waters Influence of isoprene on aciditification of atmospheric waters Interaction of biosphere and atmosphere Interaction of biosphere and atmosphere

19 Thank you for your attention for your attention

20 Mn(II) (+ O2, S(IV))→ Mn(III) S 2 O 8 2– → SO 4 – + SO 4 – Mn(III) + SO 3 2– → Mn(II) + SO 3 – SO 3 – + O 2 → SO 5 – SO 5 – + SO 3 2– → SO 5 2– + SO 3 – SO 5 – + SO 3 2– → SO 4 2– + SO 4 – SO 5 – + HSO 3 – → HSO 5 – + SO 3 – SO 5 – + HSO 3 – → SO 4 2– + SO 4 – + H + SO 4 – + SO 3 2– → SO 4 2– + SO 3 – SO 4 – + HSO 3 – → SO 4 2– + SO 3 – + H + HSO 5 – + HSO 3 – → SO 4 2– + SO 4 2– + 2 H + SO 5 2– + SO 3 2– → SO 4 2– + SO 4 2– SO 5 – + Mn(II) → SO 5 2– + Mn(III) SO 5 – + Mn(II) → SO 4 2– + Mn(III) (+ OH – ) SO 4 – + Mn(II) → SO 4 2– + Mn(III) SO 5 – + SO 5 – → SO 4 – + SO 4 – + O 2 SO 4 – + S 2 O 8 2– → SO 4 2– + S 2 O 8 – SO 3 – + SO 3 – → S 2 O 6 2– SO 4 – + SO 4 – → S 2 O 8 2– SO 5 – + SO 5 – → S 2 O 8 2– + O a 5-2a 6 6a 7 7a