Particulate, Gas & Vapor (Sampling Equipment) Cindy Hammons

PARTICULATE

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

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)

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

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

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

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

Type of Sampling  Area sampling  Personal sampling

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

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

GAS & VAPOR

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

 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

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

Physicochemical Properties  Solubility  Melting and boiling points  Vapor pressure  Vapor density or relative density  Flash point

CSDS  Physicochemical properties

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

Type of Sampling  Area sampling  Personal sampling

Sampling Equipment  Real time  Non real time

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

Thank You