Chemiluminescent method and apparatus for the detection of ozone
Parallel flow diffusion battery
Apparatus for sampling and characterizing aerosols
Method for charging particles suspended in gases
Method for the quantitative and qualitative characterization of substances contained in a gaseous carrier medium Patent #: 4769548
ApplicationNo. 06/926903 filed on 11/03/1986
US Classes:250/379, With means to supply the gas250/382, With means to ionize the gas250/423P, Photoionization type324/464For analysis of gas, vapor, or particles of matter
ExaminersPrimary: Fields, Carolyn E.
Attorney, Agent or Firm
International ClassesG01N 27/66 (20060101)
G01N 27/64 (20060101)
Foreign Application Priority Data1984-05-11 DE
AbstractAerosol particles, resulting from the combustion of organic substances with insufficient oxygen supply, usually contain toxic, higher hydrocarbonic substances (e.g. tar) on their surface. These substances, e.g. tar, has the property to be photoelectrically more active than other substances contained in the atmosphere. In the method and apparatus according to the invention an aerosol, i.e. the carrier gas containing the particles to be characterized, is used which has been brought to at least one predetermined temperature sufficient for evaporation or decomposition or preventing condensation of molecules on particles of said aerosol that quench or enhance photoelectric activity. Such aerosol is exposed to electromagnetic radiation and, thereby, activated to electron emission. Thereafter the charge of the photoelectrically positively charged particles is determined by means of size selective filter means which are connected to current or charge measuring equipment. From the measured values information can be derived about the nature and amount of said molecules and about the remaining surface of the aerosol particles. Additional information on the coatings and also on the species of hydrocarbon may be obtained by observing the measured values as a function of temperature. The method and apparatus are particularly useful for the measurement of air pollution.