Uptake of nitrate and sulfate on dust aerosols during TRACE‐P

[1] Aerosol data collected near Asia on the DC-8 aircraft platform during TRACE-P has been examined for evidence of uptake of NO3− and SO4= on dust surfaces. Data is compared between a sector where dust was predominant and a sector where dust was less of an influence. Coincident with dust were higher mixing ratios of anthropogenic pollutants. HNO3, SO2, and CO were higher in the dust sector than the nondust sector by factors of 2.7, 6.2, and 1.5, respectively. The colocation of dust and pollution sources allowed for the uptake of NO3− and nss-SO4= on the coarse dust aerosols, increasing the mixing ratios of these particulates by factors of 5.7 and 2.6 on average. There was sufficient nss-SO4= to take up all of the NH4+ present, with enough excess nss-SO4= to also react with dust CaCO3. This suggests that the enhanced NO3− was not in fine mode NH4NO3. Particulate NO3− (p-NO3−) constituted 54% of the total NO3− (t-NO3−) on average, reaching a maximum of 72% in the dust sector. In the nondust sector, p-NO3− contributed 37% to t-NO3−, likely due to the abundance of sea salts there. In two other sectors where the influence of dust and sea salt were minimal, p-NO3− accounted for <15% of t-NO3−.

[1]  Sung-Nam Oh,et al.  Chemical composition and source signature of spring aerosol in Seoul, Korea , 2001 .

[2]  K. Pye.  Aeolian dust and dust deposits , 1987 .

[3]  J. Dibb,et al.  Aerosol chemical composition in Asian continental outflow during the TRACE‐P campaign: Comparison with PEM‐West B , 2003 .

[4]  G. Carmichael,et al.  Numerical Investigation of the Influence of Mineral Dust on the Tropospheric Chemistry of East Asia , 2000 .

[5]  G. Carmichael,et al.  A three‐dimensional modeling investigation of the evolution processes of dust and sea‐salt particles in east Asia , 2001 .

[6]  Daizhou Zhang,et al.  Nitrate and sulfate in individual Asian dust-storm particles in Beijing, China in Spring of 1995 and 1996 , 1999 .

[7]  Xingmin Meng,et al.  Provenance, transport and characteristics of modern aeolian dust in western Gansu Province, China, and interpretation of the Quaternary loess record , 1998 .

[8]  G. Carmichael,et al.  Gas-Particle Partitioning of Nitric Acid Modulated by Alkaline Aerosol , 2001 .

[9]  W. Chameides,et al.  Aqueous‐phase chemical processes in deliquescent sea‐salt aerosols: A mechanism that couples the atmospheric cycles of S and sea salt , 1992 .

[10]  B. Anderson,et al.  Chemical and physical properties of bulk aerosols within four sectors observed during TRACE‐P , 2003 .

[11]  Yuan Gao,et al.  Characteristics of Chinese aerosols determined by individual‐particle analysis , 2001 .

[12]  Gregory R. Carmichael,et al.  Long‐range transport of SO x and dust in East Asia during the PEM B Experiment , 1997 .

[13]  Y. Iwasaka,et al.  Seasonal Changes in the Concentrations of Major Cations and Anions in Precipitations in Urban Nagoya, Japan , 1998 .

[14]  H. Fuelberg,et al.  Meteorological conditions and transport pathways during the Transport and Chemical Evolution over the Pacific (TRACE-P) experiment , 2003 .

[15]  A. Goodman,et al.  A laboratory study of the heterogeneous reaction of nitric acid on calcium carbonate particles , 2000 .

[16]  J. Lelieveld,et al.  Role of mineral aerosol as a reactive surface in the global troposphere , 1996 .

[17]  James N. Galloway,et al.  Sea‐salt corrections and interpretation of constituent ratios in marine precipitation , 1986 .

[18]  Soon-Ung Park,et al.  Transport and evolution of a winter-time Yellow sand observed in Korea , 2001 .

[19]  Jimin Sun,et al.  Spatial and temporal characteristics of dust storms in China and its surrounding regions, 1960-1999 : Relations to source area and climate , 2001 .

[20]  Gregory R. Carmichael,et al.  Photochemical Oxidant Processes in the Presence of Dust: An Evaluation of the Impact of Dust on Particulate Nitrate and Ozone Formation , 1994 .

[21]  K. Okada,et al.  Nature of coarse nitrate particles in the atmosphere—A single particle approach , 1994 .

[22]  G. Carmichael,et al.  Heterogeneous reactions of NO2 and HNO3 on oxides and mineral dust: A combined laboratory and modeling study , 2001 .