Aerosol soil-derived

Caquineau, S., A. Gaudichet, L. Gomes, M.-C. Magonthier, and B. Chatenet, Saharan Dust Clay Ratio as a Relevant Tracer to Assess the Origin of Soil-Derived Aerosols, Geophys. Res. Lett., 25, 983-986 (1998). 

Particle-Particle Interactions. Loss of strong acid content of aerosol particles can also occur because of reactions between co-collected acidic and basic particles impacted together on the collection surface. This phenomenon most frequently occurs as the result of interaction of coarse (>2.5 xm diameter), alkaline, soil-derived particles with fine (<2.5 xm diameter) acidic sulfate particles (66). Particle-particle interactions with net neutralization can be reduced in many cases by sampling with a virtual impactor or a cyclone to remove coarse particles, although this procedure does not prevent the effect if external mixtures of fine particles of different acid contents are sampled. In situ methods with shorter sampling times can be used such that these topochemical reactions are less likely to occur. 

In a more recent paper Flyger and Heidam (1978) report that Greenland aerosol consists mostly of soil-derived silicon (0.043 ng m-3) and sulfates ( 0.08 ng m"3). Note sulfate was identified as sulfur. 

Fig. 7-9. Vertical mass flux of soil-derived aerosol versus the wind friction velocity for different soil types. [Adapted from Gillette (1980).] The solid line indicates a fifth-power dependence. The key on the right correlates soil type with wind erodibility groups (WEG) [after Hayes (1972)] and erodibility in units of 103 kg/ha yr [after Lyles (1977)].

In coastal seawater such as the Western Mediterranean basin, soil-derived particles originated from arid areas (in this case the Sahara). The atmospheric flux of anthropogenic trace metals, however, was dominated by aerosols from industrialized regions of Western Europe. Volcanic activity (Mount Etna) contributes selenium. The atmospheric input of Cr, Hg, Pb, and Zn into the Western Mediterranean basin is of the same order of magnitude as the riverine and coastal inputs of these components (Arnold et al. 1983). For the southern bight of the North Sea, estimates even indicate a predominance of the atmospheric input of... 

The effect of atmospheric inputs of nutrients on biological cycles is particularly important for oligotrophic oceanic provinces, and episodic deposition may even induce algal blooms. The ECS adjacent to the East Asia mainland is influenced by a monsoon climate and strong emissions of natmal and anthropogenic compounds into the atmosphere. Soil-derived dust and anthropogenic compounds are transported over the ECS via atmospheric circulation, while aerosols from the ocean also play an important role in the chemical characteristics of precipitation. 

Soil-derived partieles sueh as aluminosilicates, CaCOs, and Si02 are the seeond most abundant partiele type in indoor environment of subway stations. The relative abundanee of the sod-derived particles in subway stations are the lowest in the tunnel and the highest at the waiting room. Also secondary particles sueh as nitrates and sulfates are more abundantly encountered in the waiting room than in the platform area. The soil-derived and secondary aerosol particles are likely from the outdoor atmosphere. Therefore, the contents of those particles are higher for the samples eoUeeted at the loeations closer to the outdoor. 

Particulate pollutants are emitted from many sources. Additionally, particles are formed in the atmosphere by both chemical and physical conversions from natural and anthropogenic gaseous substances. Particulate pollutants cover a size range from <10 nm to >100 pm. The major proportion of the aerosol below 1 pm is generally man-made, including sulfates from SO2 oxidation and carbon from vehicle exhausts, for example. Particles of a greater size are frequently natural (e.g., soil-derived, marine aerosol) but this division cannot be regarded as absolute. 

Carbonaceous materials (predominantly found in the fine size mode) and sometimes the dominant fraction of the total fine particle mass (Andrews et al., 2000 Putaud et al., 2004) have been usually classified as organic carbon (OC), elemental carbon (EC), and inorganic carbon (IC). The latter fraction typically consists of mineral carbonates derived almost exclusively from soil dust (Seinfeld and Pankow, 2003). Since mineral carbonates are commonly discarded from chemical aerosol mass closures, data on total carbon (TC) content of air particulate matter at sites representing different pollution levels refers only to the sum of OC and EC... 

Much has been written in recent years about atmospheric inputs to the soil since the acid rain problem has been recognised. Soils receive both wet deposition, ie, precipitation as rain or snow and dry deposition in which aerosols are deposited on the surface. Although precipitation is very dilute it can be an important source for some elements, cyclic salts which are derived from the oceans and transported to the land surface in the normal hydrological cycling of elements. Fuge and Johnson (1986) concluded that most iodine in soils is derived from the atmosphere and, hence, the oceans. Normally, however, rain makes only a very small contribution to the composi-... 

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