Introduction
Air sampling is a vital method of monitoring workers’ exposure to these potential airborne workplace hazards. Air sampling is carried out to ensure that workplace or environmental air is meeting regulatory standards and to help Occupational Hygiene and Health & Safety professionals assess employee exposure to airborne hazards. By consistently measuring the concentration of airborne contaminants, steps can be taken to reduce workers’ exposure, thereby helping to prevent chronic respiratory diseases such as asthma, as well as occupational cancers.
Air is a vital element to sustain lives of not only human being but all organisms. With social organization and economic developed, quality of life is required to be enhanced relatively; therefore, air monitoring is one of the important means to accomplish this goal, for example, monitoring the suspended particulate matter (PM2.5) and air of workplace. Another key point to remember is that air sampling is the most crucial steps in surveillance of air pollution due to its direct effect on results.
The objective of air sampling is to assess the hazardous materials and determine the ambient air quality. Air sampling is to collect a known volume of air which contains analytes of interest through the appropriate sampling medium by a vacuum pump or sampling pump. The common methods include direct sampling (e.g. gas sampling bag, glass bulb and syringe), solid sorbent (e.g. granular), liquid sorbent (e.g. bubblers and impingers), etc.
The vacuum pump is an essential tool in air sampling for collecting and concentrating the analytes into the medium; hence, it is required to maintain at a known and fairly constant flow rate to ensure the accuracy of sampling volume. The pump selection varies depending on target analytes (particulates or chemicals) and estimated sampling volume (or quantity) and period.
Methods
Active air sampling for airborne PM and other aerosols (including water droplets and other aerosolized liquids) requires specialized pumps and sample collection devices (of which there are many different types) that need careful calibration, cleaning, and maintenance.
Types of Air Sampling Equipment
Air sampling equipment comes in various forms, so your company can choose the air sampling methods and tools that will work best for your specific applications.
Cassettes
Filter cassettes are the basic units of air sampling. Many sampling cassettes work with pumps to collect particulates from the air — they are particularly effective for mold collection. Facilities can use the cylinder-shaped cassettes to collect air contaminants from work environments and send them to the laboratory for analysis.
Cassettes sometimes contain preloaded filters for convenience in air sampling. Unlike other pieces of equipment, these cassettes do not require weighing or assembly before use.
Pumps
Air sampling pumps pair with filter media to collect contaminants from the air. They are useful for area sampling, indoor air quality sampling and personal sampling, and they work well for many contaminants, including asbestos, beryllium, hazardous particulates, lead, mold spores, and respirable dust and silica.
Bubblers and Impingers
Bubblers and impingers often work with an area pump to sample contaminants in a defined area. Impingers often work best for particulates, and bubblers are ideal for gases and vapors. They require liquid for their work — they collect their contaminants by bubbling the air through a liquid that binds to the contaminants.
Filters and Filter Media
Filters work by passing air through membranes filled with small pores. The air can pass through, while the tiny holes trap the contaminants on the other side of the media. Filter membranes come in a variety of different materials — mixed cellulose ester (MCE), polyvinyl chloride (PVC), polycarbonate track-etch (PCTE), polytetrafluoroethylene (PTFE), glass fiber, quartz and even silver.
Cyclones
Cyclone assemblies connect to filter cassettes to filter larger, nontoxic particles out of the air. They contain a centrifuge where the rapid rotation of air forces larger particles down into a grit pot. Respirable particles continue on and become trapped in the filter cassette.
Inhalable Samplers
Inhalable samplers collect particles of a size that makes them particularly likely to enter the body through inhalation — that is, particles of up to 100 micrometers in diameter. They help companies determine the risk of contaminant inhalation for their workers.
Applications
- Medical industry, such as microbial monitoring in operating theatres and clean room
- Electronics industry, such as airborne molecular contamination (AMC) analysis
- Workplace monitoring, such as harmful dusts, fiber, fumes or gas