Identification of contaminant sources in enclosed spaces by a single sensor

T. Zhang, Q. Chen

Research output: Journal article publicationJournal articleAcademic researchpeer-review

85 Citations (Scopus)


To protect occupants from infectious diseases or possible chemical/biological agents released by a terrorist in an enclosed space, such as an airliner cabin, it is critical to identify gaseous contaminant source locations and strengths. This paper identified the source locations and strengths by solving inverse contaminant transport with the quasi-reversibility (QR) and pseudo-reversibility (PR) methods. The QR method replaces the second-order diffusion term in the contaminant transport equation with a fourth-order stabilization term. By using the airflow pattern calculated by computational fluid dynamics (CFD) and the time when the peak contaminant concentration was measured by a sensor in downstream, the QR method solves the backward probability density function (PDF) of contaminant source location. The PR method reverses the airflow calculated by CFD and solves the PDF in the same manner as the QR method. The position with the highest PDF is the location of the contaminant source. The source strength can be further determined by scaling the nominal contaminant concentration computed by CFD with the concentration measured by the sensor. By using a two-dimensional and a three-dimensional aircraft cabin as examples of enclosed spaces, the two methods can identify contaminant source locations and strengths in the cabins if the sensors are placed in the downstream location of the sources. The QR method performed slightly better than the PR method but with a longer computing time.

Original languageEnglish
Pages (from-to)439-449
Number of pages11
JournalIndoor Air
Issue number6
Publication statusPublished - Dec 2007


  • Backward location probability
  • Computational fluid dynamics
  • Indoor environment
  • Inverse modeling
  • Pseudo-reversibility equation
  • Quasi-reversibility equation

ASJC Scopus subject areas

  • Environmental Engineering
  • Building and Construction
  • Public Health, Environmental and Occupational Health


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