Particulate, Gas & Vapor (Sampling Equipment)

1. Particulate, Gas & Vapor(Sampling Equipment)

2. PARTICULATE

3. Definitions • Aerosols – the dispersion of solid or liquid particles in the gaseous medium • Dust – dispersion of solid particles in the gaseous medium • Fumes – solid particles in a gaseous medium formed by condensation of solid materials (vapor) • Smoke – usually but not necessarily consist of solid particles

4. Shape, Size and Distribution • Various shape, size and density of particulate • AED is the diameter of a unit density sphere having the same settling velocity as the particle concern • Polydisperse dust cloud (geometric mean and geometric standard deviation)

5. Aerodynamic Behavior In Airstream • Impaction – proportional to the momentum i.e. mass and velocity • Sedimentation – proportional to its diameter • Diffusion – for particles < 0.1um

6. Size Selective and Selected Area of Deposition • Nasopharyngeal deposition (upper respiratory tract) – 7 to 20um • Tracheobronchial (conducting airways) – 5 to 7um • Alveolar region (gas exchange area) – 0.5 – 5um

7. Inhaled Dust Fractions (Sampling Instrument) • Respirable dust – the dust fraction that will penetrate to the unciliated portion of the lungs

8. Purpose of Sampling • Compliance with the requirement of the law • Health risk assessment • Epidemiological study • Assessment of control measures

9. Type of Sampling • Area sampling • Personal sampling

10. Type of Sample & Equipment • Total dust • Inspirable dust – 7 hole sampler, IOM sampler, close face sampler • Respirable dust – BMRC horizontal elutriator, AEC cyclone • Thoracic dust – vertical elutriator • Fibers – open face sampler with cowl

11. Sampling Equipment • Real time – piezobalance, dust counter etc • Non real time – filtration, impaction (cascade impactor)

12. GAS & VAPOR

13. Definitions • Gas – a state of matter in which a substance completely fills the region in which it is contained; has very low density and viscosity; can expand and contract greatly in response to changes in temperature and pressure; and easily diffuses into other gases e.g., CO, CO2, HCN, NH4, SO2, H2S, N2O, O3, Formaldehyde, phosgene, arsine, vinyl chloride etc

14. Vapour – the gaseous state or form of a substance which is normally in the liquid or solid state at room temperature and pressure. The liquid or solid may be reduced to the vapor by the action of heat. A vapor can be liquefied by a suitable increase in pressure e.g., toluene, xylene, alcohol, C2S, benzene, carbon tetrachloride etc

15. Physiological Effects • Carcinogens – vinyl chloride, benzene, benzidine, B-napthylamine, formaldehyde • Systemic poisons – C2S, parathion, hexane, chlorinated hydrocarbon • Asphyxiation – CO, CH4, HS, Na Nitrite • Irritation – acid, alkali, O3, N2O, phosgene • Anesthetic/narcosis – alcohol, ketones • Sensitizer – TDI, formaldehyde

16. Physicochemical Properties • Solubility • Melting and boiling points • Vapor pressure • Vapor density or relative density • Flash point

17. CSDS • Physicochemical properties

18. Purpose of Sampling • Compliance with the requirement of the law • Health risk assessment • Epidemiological study • Assessment of control measures

19. Type of Sampling • Area sampling • Personal sampling

20. Sampling Equipment • Real time • Non real time

21. Sampling Equipment (examples) • Charcoal tubes with pump • Passive sampler (diffusion membrane) • Bubbler (midget impinger) • MIRAN • Portable gas chromatography • Detector tubes