Pengelolaan Polutan Udara di dalam Ruangan

1. Pengelolaan Polutan Udara di dalam Ruangan Oleh Sudrajat PPLH- Unmul 2003

2. Non-Inertial Samplers • E.g. Filtration, Electrostatic Precipitation, thermal precipitators, and Condensation traps • Do not rely on inertia of particles for operation, thus less reliant on particle size (less particle size bias)

3. Filtration • Simple equipment requirements • Adaptable to personal sampling • Less particle size bias (allows large and small particle collection; dependent on inlet size/shape) • Continuous sampling over extended period • Wide variety of sampling rates • However, problems with desiccation leading to reduced viability and difficulties with particle recovery efficiencies

4. Filter Media • Fiborous- mesh of material whose fibers are randomly oriented (creating nominal pore size); depth filter entrainment • Glass fiber (works for proteinaceous bioaerosols) • Membrane- a gel with interconnected pores of uniform size (absolute pore size); depth filter entrainment • Cellulose esters (commonly used for water and other liquids for microbe concentration), PVC, PTFE, nylon, gelatin • Flat disc or etched membranes- defined holes or pores (absolute pore size); surface collection • Silver, aluminum oxide, polycarbonate (most commonly filter media for collection of microbes from air)

5. Filters

6. Electrostatic Precipitators • Particles removed from air stream by electrical rather than inertial forces • Low pressure drop; low power; capable of large volume sampling and high rates • Draws air across high voltage field or corona discharge inducing charge; surface collection • Can be effective for very small particles, as well as larger ones • Problem with ozone production; loss of viability • Examples- • LVAS • LEAP

7. Thermal Precipitation and Condensation Traps • Thermal precipitation • Not commonly used • Based on Thermophoretic motion • Air passed between two plates (one heated and one cooled); particles collected on cooler plate • Condensation trap • Relies on manipulation of relative humidity • Bioaerosol used as condensation nuclei • Particles collected by settling

8. Recovery from Air • Factors that will affect the recovery of microbes from air samples: • Sampling Rate • Environmental Factors may reduce sampling efficiency (e.g. Swirling winds) • Sampling Time • Organism Type and Distribution • Particle Size and Distribution • Target of detection method to be utilized • Sampler Choice • Collection efficiency • Recovery efficiency • Particle Size Bias

9. Recovery from Air • Factors that will affect the recovery of microbes from air samples: • Sampling Rate and Sampling Time (sampled volume) • Concentration factor • Environmental Factors may reduce sampling efficiency (e.g. Swirling winds) • Organism Type and Distribution (need for replication) • Target of detection method to be utilized • Sampler Choice • Collection efficiency (d50) • Retention efficiency • Recovery efficiency • Particle Size Bias • Loss of viability • Sampler Calibration

10. Collection Efficiency: Flowing Air

11. Sample Line Losses • To minimize make as short as possible, minimize angles

12. Separation and Purification

13. Separation and Purification Methods • Purification, separation and secondary concentration of target microbes in primary sample or sample concentrate • Separate target microbes from other particles and from solutes • Reduce sample size (further concentrate)

14. Separation/Purification Methods • Variety of physical, chemical and immunochemical methods: • Sedimentation and flotation (primarily parasites) • Precipitation (viruses) • Filtration (all classes) • Immunomagnetic separation or IMS (all classes) • Flow cytometry (bacteria and parasites); an analysis, too

15. Secondary Concentration and Purification • PEG (polyethylene glycol) • Organic Flocculation • IMS (Immunomagnetic separation) • Ligand capture • BEaDs (Biodetection Enabling Device) • Capillary Electrophoresis • Microfluidics • Nucleic Acid Extraction • Spin Column Chromatography • Floatation • Sedimentation • Enrichment

16. Chemical Precipitation Methods • Viruses: precipitate with polyethylene glycol or aluminum hydroxide • resuspend PEG precipitate in aqueous buffer • dissolve aluminum floc in dilute acid solution • both have been used as second-step concentration and purification methods • Parasites: precipitate with calcium carbonate • dissolve precipitate in dilute sulfamic acid

17. Other Recovery and Concentration Methods • Minerals, such as iron oxide and talc; used to adsorb viruses • Synthetic resins: ion exchange and adsorbent • Other granular media: glass beads and sand Less widely used; less reliable, cumbersome; uncertain elution, desorption, exchange efficiencies

18. Initial Recovery and Concentration of Pathogens • Flotation centrifugation • Layer or suspend samples or microbes in medium of density greater than microbe density; centrifuge; microbes float to surface; recover them from top layer • Isopycnic or buoyant density gradient centrifugation • Layer or suspend samples or microbes in a medium with varying density with depth but having a density = to the microbe at one depth. • Microbes migrate to the depth having their density (isopycnic) • Recover them from this specific layer Isopycnic density gradient: microbe density = medium density at one depth Flotation: microbe density < medium density

19. Immunomagnetic Separation Y Antibody Bead Y Y Y Microbe

20. Virus Capture Plus RT-PCR to Detect Infectious Viruses - The sCAR System • The cell receptor gene for Coxsackieviruses and Adenoviruses has been cloned and expressed, producing a soluble protein receptor, sCAR • Expressed, purified and bound sCAR to solid phases to capture infectious Coxsackieviruses from environmental samples • The nucleic acid of the sCAR-captured viruses is RT-PCR amplified for detection and quantitation

21. Application of sCAR with Para-Magnetic Beads for Virus Particle Capture and then RT-PCR sCAR purification Covalent coupling to paramagnetic beads Culture + media; :sCAR produced Blocking post-coupling (RT-) PCR : sCAR NA extraction Sample containing viruses : Virus Particle : Blocking protein Amine Terminated Support Magnetic Bead : BioSpheres(Biosource) Pre-coated to provide available amine groups for covalent coupling of proteins or other ligands by glutaraldehyde-mediated coupling method