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Biomedical subjects

R J Charlson

Publications and source records attributed to R J Charlson.

13 recordsLinked to original sources
PubMed1977

Ammonia in the human airways: neutralization of inspired acid sulfate aerosols.

In the human being, expired ammonia concentrations from 7 to 520 micrograms per cubic meter are controlled by the last airway segment traversed by the air, and such concentrations are higher in the mouth than nose. Inspired submicrometric sulfuric acid aerosol at a mass concentration of 600 +/- 100 micrograms per cubic meter was found to be an ammonium salt with an average ammonium to sulfate molar ratio of greater than or equal to 1, when sampled within 0.5 second after exhalation.

Aerosols↗
PubMed1976

Influence of relative humidity on functional effects of an inhaled SO2-aerosol mixture.

Lightly anesthetized guinea pigs were exposed to 1 ppm of sulfur dioxide (SO2) and 1 mg per m3 of sodium chloride aerosol, individually and in combination, at low and high relative humidities. At low relative humidity (less than 40 per cent) the aerosol was a crystal, at high relative humidity (greater than 80 per cent) a droplet. Exposures lasted one hour. Changes in pulmonary mechanical function characterized by an increase in flow resistance and decrease in compliance were seen only when the mixture was administered at high relative humidity. The effect is ascribed to absorption of the highly soluble SO2 into the droplet before inhalation.

Aerosols↗
PubMed1974

Sulfuric acid-ammonium sulfate aerosol: optical detection in the St. Louis region.

Nephelometric sensing of the deliquescence of ammonium sulfate produced by the reaction of sulfuric acid or ammonium bisulfate aerosol with ammonia provides a means for detecting these substances in air. Field experiments show them to be the dominant substances in the submicrometer, light-scattering aerosol in the St. Louis region.

Aerosols↗
PubMed1970

Atmospheric aerosol: does a background level exist?

Measurements of light-scattering made with an integrating nephelometer at Point Barrow, Alaska, and Mount Olympus, Washington, are in agreement in magnitude, and both sets of measurements also are in agreement with other measurements of light-scattering and turbidity made in remote locations. This agreement suggests that a background level of aerosol exists and that the concept of a background is applicable.

Aerosols↗
PubMed1968

Urban haze: the extent of automotive contribution.

Observation of the correlation between nitrogen oxides and the extinction coefficient of atmospheric air suggests that the automobile exhaust aerosol (nonphotochemical) may be important to visibility in cities.

Aerosols↗