异戊二烯有机示踪物的羟基非均相氧化

When the tracer-based method is applied to analyze the contribution of various gas precursors to secondary organic aerosols (SOA), the heterogeneous oxidation reactions between organic tracers and atmospheric oxidants (·OH, O₃, NO₃, etc.) will lead to uncertainty in source apportionment. In this paper, the secondary organic tracers of isoprene SOA, 2-methylerythritol (2-ME) and its analogue erythritol (AME) pure substance were studied by oxidation by ·OH under different experimental conditions in an atmospheric smog chamber. The experimental results show that the heterogeneous oxidation reaction effective rate constant of AME and ·OH is in the range of 3.64×10^-11 ~ 4.15×10^-11cm³/ (molecule·s) at 24.7 (±1.5) ℃.The effective lifetime of AME is about 4.46 ~ 5.09h when the average typical concentration of atmospheric ·OH is 1.5×10⁶molecule/cm³. The effective rate constant of 2-ME ranges from 4.39×10^-12 to 9.05×10^-12cm³/(molecule·s), corresponding to the atmospheric lifetime of 0.85 ~ 1.76d. The ·OH oxidation reaction of isoprene organic tracer was significant, and tracer-based method would underestimate the contribution of isoprene to SOA.