Treesearch

The acid properties of particles have been investigated by means of measuring the content of mainly strong acid in leaching solutions of particle samples and in drain water from trees. The measurements are based on Gran's plot and on a study of its curvature.

A theoretical model describing the general interaction between atmospheric trace gases, such as SO2, NH3, CO2 and O2, chemical reactant gaseous product H2SO4 and hydrometeors containing NaCl is proposed to study a possible mechanism for hydrochloric acid production in non-precipitating cloud and the determination of the pH value of cloud droplets. Four different cloud droplet distributions have been used to estimate the upper limit of the amount of gaseous HCl released into the atmosphere resulting from the evaporation of cloud droplets. It is shown that the acid production and the amount...

Acidity of rain water is a major concern due to the progressive acidification of soils, its effect of flora and fauna and its corrosiveness to metals. Sulfur dioxide, through chemical transformations and atmospheric scavenging, is thought to be one of the major contributors to the acidity of rainwater. The straightforward oxidation of SO2 to SO4 in the presence of ammonia and metal oxides should lead to a resulting pH higher than what is usually encountered and also to much faster disappearance of SO2 during rain. These apparently contradictory conclusions may be reconciled by a more...

Standard procedures for determining the pH of rain samples usually involve substantial delays from the time of rainfall to the time of analysis. This assumes that no change in pH occurs during the storage period. We have found that this is not always true. We have determined that individual rain water samples possess a time dependent pH which can be correlated with the surface wind trajectories terminating at our sampling location (Schenectady, New York). Our preliminary investigations have identified four characteristic time dependent behaviors: 1) if the trajectories generally proceeded...

Atmospheric dust originates from three sources, terrestrial airborn matter, volcanic, and cosmic. Terrestrial natural dust makes up the main bulk reflecting the soil composition to 150 miles away. Soil erosion from flood plains, plowed fields and construction sites are the main source. Quartz, feldspar, the carbonates calcite and dolomite, and clay minerals are the components in decreasing order of frequency. Natural dust in the atmosphere interacts with rainwater converting the carbonates to benign gypsum (CaSO4·2 H2O). Naturally leached soils produce less calcite than unweathered...

It is a truism for the living environment that life cannot sustain itself on its own wastes. The environment has self-cleansing properties which permit the dilution, reconstitution, and reuse by other natural processes of waste. These self-operative properties are what produces the flow of dynamic change that renews what is renewable within nature. The forces for renewal are powerful but they are not infinite. Already mankind has found the means to disrupt them in part and, unless steps are promptly taken to counteract the present trends, mankind will inadvertently and indifferently risk...

Air pollution is an international problem of the greatest dimensions. The continuous expansion of production and consumption in modern society is accompanied by the steadily increasing emission of air pollutants of different types. It is generally recognized that air pollutants can be transported in substantial amounts over distances of 1000 - 2000 km. This phenomenon has been studied with special attention being focused on acid sulphur compounds, which are the main cause of acid precipitation.

The changing acidity of air and precipitation over most of Europe and part of U. S. is only part of a larger problem--changes of the chemical climate caused by a variety of emissions into the atmosphere (13, 36). These emissions may create a local, a regional or a global situation depending only on the life-time of the pollutants in the atmosphere. The atmospheric sciences give some answers in this respect, but not all. Soils, vegetation and surface waters act not only as a passive sink for elements in the atmosphere. Several feed-back mechanisms take place including continuous exchange,...

Our ability to simulate atmospheric processes that affect the life cycle of pollution is reviewed. The transport process is considered on three scales (a) the near-source or single-plume dispersion problem, (b) the multiple-source dispersion problem, and (c) the long-range transport. Modeling the first of these is shown to be well within the capability of generally available techniques, although determining the input parameters is often difficult. The second scale has been well studied within the context of urban diffusion and is a very productive area of current research. Finally,...

The mechanisms and rates of conversion of sulfur dioxide to sulfur trioxide, sulfuric acid, and other "sulfate" aerosol precursors are considered in view of current knowledge related to atmospheric reactions and chemical kinetics. Several heterogeneous pathways exist for SO2 oxidation promoted on solid catalyst particles and in aqueous aerosol solutions in ambient air. The rates of these processes are of questionable significance in SO2-containing gases which are well removed from pollutant sources and highly diluted through turbulent diffusion and transport mechanisms. Computer simulations...