Mutual Impact of Mineral and Organic Components in Atmospheric Aerosol

Izvestiya, Atmospheric and Oceanic Physics - The effect of ammonium sulfate ((NH4)2SO4) on the condensation of low-volatile organic compounds in atmospheric aerosol is considered. Using the UNIFAC...     

Modeling the Regional Influence of Ions on Aerosol Formation in the Atmosphere

Izvestiya, Atmospheric and Oceanic Physics - The results of numerical calculations of the variability of number concentrations of aerosol particles of different sizes and the rates of ion-induced...     

The role of sulfate aerosol in the formation of cloudiness over the sea

We estimate the impact of sulfate aerosols on cloudiness formation over the sea in the middle troposphere and the involvement of these particles in the formation of polar stratospheric clouds (PSCs) in the lower stratosphere. The first of these problems is solved using a combined model of moist convection and the formation of cloudiness and sulfate aerosols in the troposphere and lower stratosphere over the sea, incorporating natural emissions of sulfur-containing compounds. We have found that a significant source of condensation nuclei in the troposphere is the photochemical transformation of biogenic dimethyl sulfide (in addition to NaCl). The results of numerical experiments indicate that the absence of sulfate aerosols hinders the cloudiness formation over the sea in the middle and upper troposphere. The problem of sulfate aerosol involvement in the formation of supercooled ternary solutions (STSs) (PSC Type Ib) in the lower stratosphere is solved using a mathematical model of global transport of multicomponent gas pollutants and aerosols in the atmosphere. Using the combined model, numerical experiments were performed for the winter season in both hemispheres. Sulfate aerosols were found to really participate in the formation of STS particles. Without their participation, the formation of STS particles in the lower stratosphere would be hindered. We present the results of numerical calculations and discuss the distribution of concentrations of gaseous nitric and sulfuric acids, as well as mass concentrations of these components in STS particles.     

Geotraverse across the Sikhote Alin — The Sea of Japan — The Honshu Island — The Pacific

The paper presents the results of geological-geophysical research carried out during the Soviet-Japanese cooperative study of the structure and dynamics of the Earth's crust and upper mantle in the transition zone from the Pacific Ocean to the Asian continent. The 300 km deep geological-geophysical section of the tectonosphere (geotraverse) has been compiled on the basis of combined interpretations of seismic, geological, petrographic, gravimetric, magnetometric, electromagnetic and heat flow measurements. Estimates were made of deep temperatures along the geotraverse and of the depths of the partial melting level that can be identified with the upper boundary of the asthenosphere.     

Hydrocarbonates in atmospheric precipitation of Moscow: Monitoring data and analysis

Based on atmospheric precipitation monitoring data for Moscow, we have revealed a number of episodes when the content of hydrocarbonates repeatedly surpasses the equilibrium level. These facts are associated with the complex structure of precipitation, which is caused by differences in the chemical composition of condensation nuclei. As a result, the underlying surface involves two groups of drops with acidities of different nature. The acidity of the first (“metal”) group is determined by the carbonate equilibrium with atmospheric CO₂ and dissolved carbonates of alkaline and alkaline earth metals. The acidity of the second (“ammonium”) group is characterized by the balance between ammonia absorbed from the air and atmospheric acids. Because of this, the precipitation acidity measured during the monitoring is regulated not only in the air but also in the condensate collector. The mixing of the metal and ammonium groups of precipitation is accompanied by only a partial conversion of hydrocarbonates into dissolved CO₂. Its termination is hindered when CO₂ actually ceases to enter the atmosphere due to mass-exchange deceleration. As a result, the content of hydrocarbonates in the collector exceeds the equilibrium level. Some estimates indicate that the acidity of the ammonia component of precipitation can be much higher than the acidity according to monitoring data. This should be taken into account in estimating the health and environmental impacts. The true level of acid rain hazard can be estimated only by measuring the acidity of individual drops, whereas the results obtained with modern tools of monitoring can underestimate this hazard.     

On the Nature of Aerosol Particles in the Atmosphere of Irkutsk

Monitoring data on the ion composition of precipitation and the water-soluble fraction of aerosol have been used to identify two types of aerosol particles in the surface atmosphere of Irkutsk (“metal” and “ammonia” groups). The aerosol acidity is basically governed by the acidity of ammonia particles, and the ion composition depends on air relative humidity (RH). Preliminary estimates are given for the distribution of major cations and anions by aerosol groups.     

Seasonal Variability of the Ion Composition,Phase State,and Mass Concentration of Aerosol in the Rural and Urban Atmosphere over Belgium (2001–2003)

Field data on the ion composition and mass concentration of aerosol in the rural (Wingene) and urban (Antwerp) regions of Belgium and the results of their thermodynamic analysis are presented. Ammonium nitrate and ammonium sulfate are found to be the major water-soluble components of aerosol particles. The seasonal variability of mass concentration, phase state, and ion composition of aerosol particles is largely determined by variations in temperature and relative humidity. It is shown that the content of ammonium nitrate and ammonium sulfate in PM2.5 is close to their thermodynamic equilibrium concentrations.     

Modeling the Influence of Ions on the Dynamics of Formation of Atmospheric Aerosol

Izvestiya, Atmospheric and Oceanic Physics - This paper describes a new numerical model of transport and transformation of gaseous and aerosol species in the atmosphere incorporating...     

Sulfate Sources in Carbonaceous Aerosol Particles in the Urban Atmosphere: The Case of Irkutsk

Izvestiya, Atmospheric and Oceanic Physics - According to monitoring data, it is found that the main source of sulfates in carbonaceous particles in the atmosphere of Irkutsk is sulfur dioxide...