Dust is a common pollution of the atmosphere, especially in parts of the world with dry land. Fine particles can increase in periods of serious drought particularly during the summer months. Quality and visibility of air reduces by fine particles and may have bad effects in health, especially for people who already have breathing related problems.
What is Dust?
Dust are fine particles, dry powder consisting of solid particles carried by air currents. These are generated by disintegration or fracture process, such as grinding, crushing, or impact and recirculates by movement of equipment, movement of workers, wind, release of previously generated dust during processing operations such as loading, dumping and transferring.
There are standard definitions used for dust based on the particle sizes as follows:
Total Inhalable Dust – This is the fraction of airborne particles which enters the nose and mouth during normal breathing. It is made up of particles of 100 microns diameter and less.
Thoracic Dust – This is the fraction approximately 10 microns diameter and less. This is also referred to as the PM10 in the USA. This fraction will pass through the nose and throat, and reach into the lungs.
Respirable Dust – This fraction is the particles approximately 5 microns and less. It certainly penetrates into the gas exchange region of the lungs, and is therefore the most hazardous particulate size.
Measurement Methodology and The Limit Values for Dust
Air samples are collected on pre-weighed 37 mm polyvinyl chloride (PVC) filter papers contained in cassette filter holders
Threshold limit values (TLV) are based on Rule 1073, Table 8a of the Occupational Safety and Health Standards.
Health Hazards of Dust
- Occupational respiratory diseases
- Irritation to eyes, nose, throat
- Skin irritation
Excessive Exposure to Harmful Dusts Can Cause:
- Pneumoconiosis – a dust related lung disease
- Silicosis – caused by silica Dust
- Black Lung – caused by coal dust
- Asbestosis – caused by asbestos dust
Control
- Using of personal protective equipment
- Fully enclosing dusty processes
- Local exhaust ventilation
- Tools with dust extraction (vacuum) devices
- Using water to suppress dust
- Operator enclosures with an air filtration system
- Use abrasives other than sand for abrasive blasting
- Wet dust suppression system
There are 23, 812 cases caused by exposure to work place dusts over a total of 27,240 cases of occupational diseases in China, year 2010 according to the data released by International Labour Organization (ILO). These occupational diseases need an immediate attention to halt or minimize such cases.
Workplace should have designed control systems and prevention to protect our environment and its’ workers’ health. The first priority is to prevent the generation of airborne dust, and if generation cannot be prevented, then secondly, its removal.
Sources:
http://www.ilo.org/public/english//region/asro/bangkok/asiaosh/newsletr/silicosi/zou.htm
https://www.who.int/occupational_health/publications/airdust/en/
