Please enable JavaScript.

Coggle requires JavaScript to display documents.

Air sampling (Chemical pollutants (Nitrogen oxide Produce from buring…

- - - - How to overcome it?
        
        good ventilation (2 methods)
        
        Natural - open window
        
        Mechanical - exhaust, fan
- - - - How it works?
        
        Expose the petri dish for 15 mins
        
        incubate to allow visible coloines to develop and be counted
      - Disadvantages
        
        there will be a chance of overgrown, in heavily contaminated condition
        
        not quantitative as its able to detect smaller particles or droplets
        
        vulnerable to interference and containation from non - airbotne sources
    - - Impingement
        (Low concentration of microbial contamination)
        Steps:
        
        introducing air into liquid broth allow microorganism to be trap in the liquid
        
        sample air is drawn by the suction pump through a narrow inlet into a flask containing medium
        3, - liquid can be dilute to count microorganism
        (Obsrvation of results)
        
        using staining techniques
        
        PCR or ELISA to identify specific microorganisms and locate area of contamination
        
        Disadvantage
        
        Overlong sampling items may allow some cells to mulitply in the liquid collection medium
      - Impaction
        (High concentration of microbial contamination)
        Steps:
        
        air is drawn into sampling head by a pump or fan and accelerated, through a sieve samplers
        
        produces laminar air flow through holes, impacted on soild surface of the agar medium
        
        Advantages
        
        able to handle high flow rates and large sample volume
        
        Disadvantages
        
        care must be taken, cannot sample for too long
        
        cells may be
        damaged by mechanical stress and loss viabillity