Bibliographic Details
| Title: |
Effects of Humidity and [NO3]/[N2O5] Ratio on the Heterogeneous Reaction of Fluoranthene and Pyrene with N2O5/NO3/NO 2. |
| Authors: |
Peng Zhang1, Wanqi Sun1, Nana Li1, Youfeng Wang1, Jinian Shu1, Bo Yang1 boyang@rcees.ac.cn, Liang Dong2 |
| Source: |
Environmental Science & Technology. 11/18/2014, Vol. 48 Issue 22, p13130-13137. 8p. |
| Subject Terms: |
*Humidity, *Nitrogen oxides, *Polycyclic aromatic hydrocarbons, *Atmospheric deposition, Pyrene, Fluoranthene, Gas phase reactions |
| Abstract: |
Atmospheric 2-nitrofluoranthene (2-NFL) and 2-nitropyrene (2-NPY) were two important nitro-polycyclic aromatic hydrocarbons (NPAHs). Especially, 2-NFL was recognized to be the most abundant particle associated NPAH (Ramdahl et al., 1986). In previous studies, these two products were observed in the gasphase reaction between N2O5/NO3/NO2 and their parent polycyclic aromatic hydrocarbons (PAHs), while the heterogeneous reaction generated other nitro-PAH isomers (1, 3, 7, 8-NFL and 1-NPY) (Atkinson et al. 1990). To clarify the possible reasons for this difference, the heterogeneous reactions of suspended fluoranthene (FL) and pyrene (PY) particles under different relative humidity (RH; 0.5%-43%) and [NO3]/ [N2O5] ratios were carried out. Under low humidity (0.5% RH) or a relatively high ratio of [NO3]/[N2O5], 2-NFL and 2-NPY were observed as the major nitro-FL isomers for the first time in the heterogeneous reaction. Decreasing the humidity or increasing the [NO3]/[N2O5] ratio in the reaction essentially increases the concentration radio of [NO3(g)]/[NO2+(aq)] on the particle surface (NO2+ is derived from the ionization of N2O5). Thus, it can be concluded that under different atmospheric conditions, the change of [NO3(g)]/[NO2+(aq)] in the particle surface has an influence on the product distribution of FL and PY in the atmosphere. The experimental results provide evidence for the heterogeneous formations of particle-bound 2-NFL and 2-NPY. However, relative to the gas-phase formation, they will be negligible in the real atmosphere. 2-NFL and 2-NPY observed in the ambient particles should mainly derive from deposition of gas-phase reactions. Additionally, this study also clarifies the reason for different nitro-PAHs isomers observed between gas and particulate reactions. [ABSTRACT FROM AUTHOR] |
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| Database: |
GreenFILE |
