Heterogeneous interactions of HOBr, HNO3, O3, and NO2 with deliquescent NaCl aerosols at room temperature
Heterogeneous interactions of HOBr, HNO3, O3, and NO2 with deliquescent NaCl aerosols at room temperature
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DOI：
10.1021/jp980932d
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发表时间：
1998-05-21
影响因子：
2.9
通讯作者：
Waschewsky, GCG
中科院分区：
文献类型：
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作者：
Abbatt, JPD;Waschewsky, GCG
为了更好地量化关键微量气体与海盐气溶胶相互作用的速率，我们利用气溶胶动力学流管技术研究了在75%相对湿度（RH）和室温条件下潮溶NaCl气溶胶对HOBr、HNO3、O-3和NO2的吸收动力学。结果表明，对于pH值为0.3的高酸性气溶胶，以及使用0.25 M NaH2PO4/Na2HPO4缓冲液缓冲至pH值为7.2的气溶胶，HOBr的吸收系数（gamma）大于0.2。对于无缓冲的NaCl气溶胶，由于反应引起的HOBr吸收系数小于1.5 × 10（-3）。对于无缓冲的NaCl气溶胶，HNO3的吸收系数大于0.2，这是由于HNO3在盐水溶液中具有很高的溶解度。NO2和O-3在pH中性气溶胶上均表现出较低的反应性，其吸收系数上限为10（-4）。对于酸性气溶胶，在流管壁上或气溶胶上发生轻微的O-3损失，从而产生Cl-2。这些实验是首次报道的HOBr、HNO3和O-3在NaCl水溶液中损失的动力学研究，它们表明气相扩散而不是反应动力学决定了气相HNO3和HOBr在边界层中向海洋气溶胶的传质速率。此外，HOBr的结果支持了模型研究，该研究提出HOBr的吸收启动了溴化物从海盐气溶胶中的自催化释放。
To better quantify the rates at which key trace gases interact with sea-salt aerosols, the kinetics of uptake of HOBr, HNO3, O-3, and NO2 by deliquescent NaCl aerosols at 75% relative humidity (RH) and room temperature have been studied using an aerosol kinetics flow tube technique. Results for HOBr indicate that the uptake coefficient (gamma) is larger than 0.2 for highly acidic aerosols at pH 0.3 and for aerosols that have been buffered to pH 7.2 using a 0.25 M NaH2PO4/Na2HPO4 buffer. For unbuffered NaCl aerosols, the HOBr uptake coefficient due to reaction is less than 1.5 x 10(-3). For HNO3, the uptake coefficient on unbuffered, NaCl aerosols is greater than 0.2, being driven by the very high solubility of HNO3 in aqueous salt solutions. Both NO2 and O-3 show low reactivity on pH neutral aerosols with upper limits to the uptake coefficients of 10(-4) With acidic aerosols, slight O-3 loss occurs either an the walls of the flow tube or on the aerosols, giving rise to Cl-2. These experiments are the first reported kinetics studies of the loss of HOBr, HNO3, and O-3 On aqueous NaCl solutions, and they imply that gas-phase diffusion, and not reaction kinetics, determines the mass-transfer rates of gas-phase HNO3 and HOBr to marine aerosols in the boundary layer. Also, the HOBr results support modeling studies which have proposed that HOBr uptake initiates autocatalytic release of bromide from sea-salt aerosols.