Measurement of total mass concentration

1. Sampling probe - Isokinetic or sampling from still air 2. Flow rate - Rotameter or digital flowmeter 3. Filter - Nearly 100% efficiency for all size. -  13, 25, 37, 47 mm (circular) mm x 250 mm (Hi volume sampler).

4. Filter holder - Open-face: uniorm distribution of particles for analysis in microscope. - Closed-face: simple, for mass concentration measurement. Open-faceClosed-face

5. Balance - Analytical balance, 0.01 to 0.1 mg sensitivity. - Electrobalance, 0.1 to 10  g sensitivity. - Sample should be kept in the room with balance for hr until equilibrium. 6. Vacuum pump - Personal pump; low flow rate 1-4 l/min.

- Larger pumps; 100 l/min. Diaphragm pumpBlower pump for Hi-volume sampler

Calculation for mass concentration is concentration is total mass collected is flow rate is sampling time Minimum sampling volume is sampling volume is sensitivity of balance is standard concentration

Personal sampler

- Used in ocupational hygiene to evaluate workers’ exposure to aerosol. - Measuring in the breathing zone; with 30-cm radius of workers’ mouth. - Light weight, battery powered pump and plastic filter holder. - Additional size selective option available; e.g. PM-10. SKC personal sample.

SKC personal sampler taken apart.

High Volume sampler - Using 2- or 3-stage centrifugal blower to pull air in. - High flow rate: up to 1700 l/min (60 CFM). - Variable speed motor is used to keep constant flow rate that may be affected by temperature and pressure change, or pressure drop due to dust loading on filter. - Used 200 mm x 250 mm (8 in x 10 in) glass fiber filter. - A roof with 50% for sampling of 30 micron particle at wind speed of 8 km/hr.

PM-10 & PM Standard in analysis of atmospheric dust issued by the U. S. Environmental Protection Agency (EPA). - Suspended particle smaller than 10 micron in diameter. - Respirable; smaller particle travels deeper in respiratory tract. - Impactor or cyclone can be used to cut off particles greater than 10 micron hr average for 3 samplings in 3 years must not exceed 150  g/m 3. - Annual average for 24-hr sampling must not exceed 50  g/m 3. PM- 10

- Suspended particle smaller than 2.5 micron in diameter. - For study of small aerosol particles thae affect visibility. - Particles smaller than 2.5 microns usually composed of SO 4 2-, NO 3 -, NH 4 +, and C. - Toxic metals; Ni, Cd or Cr. - Organic compounds; Polyaromatic Hydrocarbons (PAH). PM- 2.5

Personal sampler for respirable dust - Using cyclone for size selection. - Flow rate of 1.9 l/min

PM-10 High Volume Sampler - For sampling of suspended particles smaller than 10 micron.

PM-10/PM-2.5 Dichotomous Sampler - Classifying particles in 2 size range; 10 micron and 2.5 micron. - Using virtual impactor.