Mineral dust is a major component of atmospheric aerosol that can impact both the climate and the oxidative capacity of the atmosphere. It has been recently suggested that heterogeneous processes on natural mineral dusts can act as a sink of volatile organic compounds (VOCs) and possibly as a sources of oxygenated volatile organic compounds (OVOCs). More precisely, literature findings suggest that compounds such as isoprene (ISP), the highest emitted biogenic volatile organic compound (BVOC) in the atmosphere, could be involved in heterogeneous processes on atmospheric particles and could account for OVOC formation. Hence, within this framework, the adsorption of ISP on Gobi dust was investigated in the temperature (T) and relative humidity (RH) ranges of 253–358 K and <0.01–10%, respectively, using zero air as the bath gas. The kinetic measurements were performed using a novel experimental setup equipped with a selected-ion flow-tube mass spectrometer (SIFT-MS) for gas-phase monitoring. The initial uptake coefficient, γ₀, of ISP was measured as a function of several parameters (ISP mass, temperature, and RH). γ₀ is evidenced as inversely dependent upon the RH and dependent upon the temperature according to the empirical equations γ₀ = 2.7 × 10^–10/(0.005 + RH^1.44) and γ₀ = (5.30 ± 1.5) × 10^–7 exp[(1376 ± 133)/T], respectively. Furthermore, adsorption isotherms of ISP were determined, and the results were simulated with the Langmuir adsorption model to obtain the partitioning constant, K_Lin, as a function of the RH and temperature according to the equations K_Lin (296 K) = 0.028/(0.604 + RH^1.54) and K_Lin = (1.392 ± 0.33) × 10^–7 exp[(3732 ± 140)/T], respectively. The effect of an increasing temperature on the reversible fraction of ISP adsorption on Gobi dust was recorded. The atmospheric lifetime of the heterogeneous loss of ISP onto Gobi dust was calculated for forested environments and found to be several years.

中文翻译：

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异戊二烯与天然戈壁粉尘的异质相互作用

矿物粉尘是大气气溶胶的主要成分，会影响气候和大气的氧化能力。最近已经提出，天然矿物粉尘上的异质过程可以充当挥发性有机化合物（VOC）的汇，并且可能充当氧化性挥发性有机化合物（OVOC）的来源。更准确地说，文献发现表明，诸如异戊二烯（ISP）这样的化合物是大气中排放量最高的生物挥发性有机化合物（BVOC），可能与大气颗粒的异质过程有关，并且可以解释OVOC的形成。因此，在此框架内，研究了在温度（T）和相对湿度（RH）范围分别为253–358 K和<0.01–10％（使用零空气作为浴液）。使用配备有用于气相监测的选择离子流管质谱仪（SIFT-MS）的新型实验装置进行动力学测量。初始摄取系数，γ ₀，的ISP被作为几个参数的函数（ISP质量，温度和RH）测量。γ ₀是根据经验公式γ证明作为成反比取决于RH和依赖于温度₀ = 2.7×10 ^-10 /(0.005 + RH ^1.44）和γ ₀ =（5.30±1.5）×10 ^-7 EXP [ （1376±133）/吨]， 分别。此外，确定了ISP的吸附等温线，并使用Langmuir吸附模型对结果进行了模拟，以根据方程K _Lin（296 K）= 0.028 /（）将分配常数K _Lin作为RH和温度的函数。0.604 + RH ^1.54）和K _Lin =（1.392±0.33）×10 ^–7 exp [（3732±140）/ T ]。记录了温度升高对戈壁粉尘上ISP吸附的可逆部分的影响。计算了在森林环境中ISP因戈壁粉尘的非均质损失而在大气中的寿命，该寿命为数年。