Wu Dui, Tie Xuexi, Deng Xuejiao
Institute of Tropical and Marine Meteorology, CMA, Guangzhou, China.
Chemosphere. 2006 Jul;64(5):749-57. doi: 10.1016/j.chemosphere.2005.11.066. Epub 2006 Jan 9.
Soluble aerosols are measured at Guangdong and Hainan Provinces of southern China. The measured chemical composition of aerosols includes F-, Cl-, NO3-, SO4=, Na+, NH4+, K+, Ca2+, and Mg2+. The locations of measurements include a mega city (Guangzhou), a medium city along the coastline (Haiko), a small city along the coastline (Shanya), and a remote island site in the South China Sea (Yongxing island). The results reveal that aerosols in this region are complex and heterogeneous. Sulfate aerosol (SO4=) has the highest concentrations in Guangzhou (approximately 41% of total soluble aerosol mass), suggesting that anthropogenic activities (e.g., coal burning) play important roles in controlling aerosol concentrations in Guangzhou. By contrast, the concentrations of chlorine (Cl-) and sodium (Na+) are higher in Yongxing than in Guangzhou, indicating that the sea salt is the dominant aerosol in this marine environment site. In the medium (Haiko) and small (Shanya) city sites, the effects of anthropogenic and marine activities on aerosols fall in between the values in the mega city and the remote island site. The measured ratio of Cl-/Na+ shows that the ratio is less than 1.16 in all observation sites. The ratio in the Guangzhou city, the Haiko city, the Shanya city, and the Yongxing island is 0.52, 0.91, 0.24, and 0.53, respectively, indicating that significantly heterogeneous chemical reactions occur on sea salt particles. Unlike those in Europe and North America, there are high concentrations of calcium (Ca+) in all observation sites. The percentage of calcium mass to the measured total soluble aerosols mass is 21, 32, 34, and 30 at Guangzhou, Haiko, Sanya, and Yongxing, respectively. The calculations show that calcium plays an important role in neutralizing aerosols. The calculated "cation/anion" (summation operator[ion+]/summation operator[ion-]) ratio is 2.5, 2.5, 3.2, and 2.1, at Guangzhou, Haiko, Shanya, and Yongxing, respectively. The high "cation/anion" ratios suggest that SO4=, NO3-, and Cl- are neutralized, and the aerosols as a whole (internally mixed), appear to be in an alkaline mode in this region. However, without taking into account for calcium, the calculated "cation/anion" ratio reduces to 1.2, 0.98, 1.3, and 0.8 at Guangzhou, Haiko, Sanya, and Yongxing, respectively. The property of aerosols switches from an alkaline mode to an acidity mode at the Haiko and Yongxing sites.
在中国南方的广东省和海南省对可溶性气溶胶进行了测量。所测量的气溶胶化学成分包括F⁻、Cl⁻、NO₃⁻、SO₄²⁻、Na⁺、NH₄⁺、K⁺、Ca²⁺和Mg²⁺。测量地点包括一个特大城市（广州）、一个沿海中型城市（海口）、一个沿海小城市（三亚）以及中国南海的一个偏远岛屿站点（永兴岛）。结果表明，该地区的气溶胶复杂且具有非均质性。硫酸盐气溶胶（SO₄²⁻）在广州的浓度最高（约占可溶性气溶胶总质量的41%），这表明人为活动（如燃煤）在控制广州的气溶胶浓度方面起着重要作用。相比之下，永兴岛的氯（Cl⁻）和钠（Na⁺）浓度高于广州，这表明海盐是这个海洋环境站点的主要气溶胶。在中型（海口）和小型（三亚）城市站点，人为活动和海洋活动对气溶胶的影响介于特大城市和偏远岛屿站点之间。所测量的Cl⁻/Na⁺比值表明，所有观测站点的该比值均小于1.16。广州市、海口市、三亚市和永兴岛的该比值分别为0.52、0.91、0.24和0.53，这表明海盐颗粒上发生了显著的非均相化学反应。与欧洲和北美不同，所有观测站点的钙（Ca⁺）浓度都很高。广州、海口、三亚和永兴的钙质量占所测量的可溶性气溶胶总质量的百分比分别为21%、32%、34%和30%。计算表明，钙在中和气溶胶方面起着重要作用。计算得出的“阳离子/阴离子”（∑[离子⁺]/∑[离子⁻]）比值在广州、海口、三亚和永兴分别为2.5、2.5、3.2和2.1。高“阳离子/阴离子”比值表明SO₄²⁻、NO₃⁻和Cl⁻被中和，并且该地区的气溶胶整体（内部混合）似乎处于碱性状态。然而，不考虑钙时，计算得出的“阳离子/阴离子”比值在广州、海口、三亚和永兴分别降至1.2、0.98、1.3和0.8。在海口和永兴站点，气溶胶的性质从碱性状态转变为酸性状态。
