its management if incorporated into IH data management systems. Canada and several European countries have been working to establish occupational exposure databases with standardized data elements and improved data quality. These databases include MEGA, COLCHIC, and CWED. Dust sampling Nuisance dust is considered to be the total dust in air including inhalable and respirable fractions. Various dust sampling methods exist that are internationally recognised. Inhalable dust is determined using the modern equivalent of the Institute of Occupational Medicine (IOM) MRE 113A monitor (see section on workplace exposure, measurement & modelling). Inhalable dust is considered to be dust of less than 100 micrometers aerodynamic equivalent diameter (AED) that enters through the nose and or mouth. See Lungs Respirable dust is sampled using a cyclone dust sampler design to sample for a specific fraction of dust AED at a set flow rate. The respirable dust fraction is dust that enters the 'deep lung' and is considered to be less than 10 micrometers AED. Nuisance, inhalable and respirable dust fractions are all sampled using a constant volumetric pump for a specific sampling period. By knowing the mass of the sample collected and the volume of air sampled, a concentration for the fraction sampled can be given in milligrams (mg) per metre cubed (m3). From such samples, the amount of inhalable or respirable dust can be determined and compared to the relevant occupational exposure limits. By use of inhalable, respirable or other suitable sampler (7 hole, 5 hole, et cetera), these dust sampling methods can also used to determine metal exposure in the air. This requires collection of the sample on a methyl-cellulose ester (MCE) filter and acid digestion of the collection media in the laboratory followed by measuring metal concentration though an atomic absorption (or emission) spectrophotometry. Both the UK Health and Safety Laboratory and NIOSH Manual of Analytical Methods have specific methodologies for a broad range of metals in air found in industrial processing (smelting, foundries, et cetera). A further method exists for the determination of asbestos, fibreglass, synthetic mineral fibre and ceramic mineral fibre dust in air. This is the membrane filter method (MFM) and requires the collection of the dust on a grided filter for estimation of exposure by the counting of 'conforming' fibres in 100 fields through a microscope. Results are quantified on the basis of number of fibres per millilitre of air (f/ml). Many countries strictly regulate the