Rainwater measurements conductivity

Studies of rainwater composition typically Include the measurement of the concentrations of a number of chemical species, conductivity, and rain volume and sometimes Include supporting measurement of winds or other meteorological parameters. Much of the desired... 

To identify systematic errors in the measurement of pH of rainwater, a careful study was conducted with 17 laboratories.19 Eight samples were provided to each laboratory, along with instructions on how to conduct the measurements. Each laboratory used two buffers to standardize pH meters. Sixteen laboratories successfully measured the pH of Unknown A (within 0.02 pH unit), which was 4.008 at 25°C. One lab whose measurement was 0.04 pH unit low had a faulty commercial standard buffer. 

At present, rainwater is routinely sampled at five sites in Thailand including urban, industrial and remote sites by the Pollution Control Department (Siriswasdi, 1997). Three of the sites measure pH, conductivity, SO and NOj, while the other sites measure only pH and conductivity. Samples are collected using wet-only automatic collectors. 

A variety of techniques to identify and quantify acid and base components in rainwater are applied to data for southern California. Charge balance calculations using major cation and anion concentration data indicate southern California probably had alkaline rain in the 1950 s and the 1960 s with the exception of the Los Angeles area which probably had acidic precipitation. Measurements of the chemical composition of precipitation collected in Pasadena, California, from February 1976 to September 1977 are compared with the charge balance and conductivity balance constraints. A chemical balance is used to determine the relative importances of different sources. The pH is found to be controlled by the interaction of bases and strong acids with nitric acid being 32% more important on an equivalent basis than sulfuric acid. The uncertainties in the various calculations are discussed. 

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