The pH of Sea Salt Aerosol

9634129 涉及海洋边界层（MBL）中海盐气溶胶的化学过程可能会显著影响对流层氧化过程;硫循环，辐射平衡和气候;以及海洋表面的痕量金属施肥。溶液pH值控制着许多涉及大气海盐的化学过程。然而，海盐气溶胶中的酸碱关系的特点非常差，气溶胶pH值的测量和模型的基础上估计范围从1到9。 可靠的测量将为解决MBL中卤素、硫、氮和痕量金属的化学循环提供关键约束。 本研究的具体研究目标是：（1）在不连续的昼夜时间内对按粒径分离的海洋气溶胶进行采样，并测量主要的离子成分：（2）通过使用微电极在现场直接测量、提取物中总碳酸盐的测量和离子平衡分析来估计海盐气溶胶pH值与粒径的函数关系;以及（3）评估海洋空气中水相和多相化学过程的相关影响。 将于1997年4月下旬和5月在百慕大的AEROCE站对MBL的空气进行取样。将在不连续的12小时、白天或夜晚使用大容量级联撞击式采样器收集气溶胶。臭氧、一氧化碳、黑碳和氡的浓度、大量气溶胶的离子组成、气溶胶的物理和光学特性以及现场气象参数将在所有或某些时间间隔内同时测量，并将提供例行的气团轨迹计算。 ***

9634129 Keene Chemical processes involving sea-salt aerosol in the marine boundary layer (MBL) may significantly impact tropospheric oxidation processes; sulfur cycling, radiation balance and climate; and trace-metal fertilization of the surface ocean. Solution pH controls many chemical processes involving atmospheric sea salt. However, acid-base relationships in sea-salt aerosol are very poorly characterized; estimates of aerosol pH based on measurements and models range from 1 to 9. Reliable measurements would provide critical constraints in resolving the chemical cycling of halogens, sulfur, nitrogen, and trace metals in the MBL. The specific research objectives of this study are: (1) to sample size-segregated marine aerosol during discrete day and night periods and to measure major ionic constituents; (2) to estimate sea-salt aerosol pH as a function of particle size via direct measurements in the field using micro-electrodes, measurement of total carbonate in extracts, and ion-balance analyses; and (3) to assess related implications for aqueous- phase and multi-phase chemical processes in marine air. MBL air will be sampled during late April and May 1997 at the AEROCE station on Bermuda. Aerosols will be collected with high-volume cascade impactors over discrete, 12-hour, day or night periods. The concentrations of ozone, carbon monoxide, black carbon, and radon, the ionic composition of bulk aerosols, the physical and optical properties of aerosols, as well as site meteorological parameters will be measured concurrently during all or some intervals, and routine air parcel trajectory calculations will be available. ***