What are airborne dust contaminants? – these are tiny, solid particles added to the natural air due to either human activities such as mining, blasting, drilling, construction, wild-fires or natural phenomena such as volcanoes, dust storms or sea sprays. Of major concern to our discussion are airborne dust contaminants from the mining, quarrying, and road construction industries. Near home examples include metalliferous dusts, rock dust, finely powdered materials, coal dust, and crystalline silica dust which in their respirable particle sizes lead to pulmonary diseases which result in loss of life. The airborne dust contaminants accumulate in the lungs with particle sizes of 100 microns being inhalable but due to self-cleaning mechanisms the particles of concern are PM10 and PM 2.5. These particles get accumulated in the thoracic region of the respiratory system. The particles having size below 4 microns move deeper into the lungs. PM 2.5 accumulates in the alveoli region of lungs. These dust particles reduce breathing capacity of the lungs. Dust particles less than 2.5 microns are more dangerous to health because they have a tendency to settle deep into the lung sacks causing different heart and lung complications. In this article, we focus on:

  • The types of airborne dust contaminants
  • Particle sizes of these airborne dust contaminants
  • Dangers of airborne dust contaminants.

What are the types of airborne dust contaminants?

The different types of particulate matter may be divided into three categories:

Primary particulate matter: directly released into the atmosphere by many human and natural sources. Primary sources cause particle pollution on their own.
Secondary particulate matter: formed by physical and chemical reactions from other pollutants, secondary sources let off gases that can form particles. Power plants and coal fires are examples of secondary sources.
Re-suspended particulate matter: after it has been deposited, particulate matter can then return into the air through wind action or road traffic disturbance in urban areas, for example.

Airborne dust contaminants are solids that are both microscopic and nanoscopic in nature and get suspended in the Earth’s atmosphere. These solid particles of different origins from mining, quarrying and road construction activities are hazardous to human health. The chemical constituents and particle size of these different types of airborne dust contaminants govern the extent to which damage is done in humans. The smaller the particles, the deeper they can penetrate the respiratory system and the more hazardous they are to breathe. Inhalable coarse particle are particles in the range 2.5 microns to 10 microns commonly known as PM10 – PM2.5. Fine particles are found in smoke and haze from activities such as blasting which makes use of explosives and have sizes up to 2.5 microns and are known as PM 2.5. To bring this into perspective they are 100 times thinner than human hair. We get into more detail about particle sizes of these airborne dust contaminants in the next section.

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What are the particle sizes of these airborne dust contaminants?

>PM10 – Particle sizes of 10 microns in diameter or more also known as visible dust with examples such as limestone and are considered least harmful to the human body owing to the ability of the body’s pulmonary filters being able to get rid of it although some dust particles such as silica are dangerous in the particle size category.

PM10 – Particle sizes less than 10 microns in diameter (invisible to the naked eye) which consists of cement dust, iron dust, textile dust and are most likely to settle in the nose or throat area and can be expelled through coughing and sneezing. The downside to this particle size is that irritation arising from them can cause short and long-term health issues such as asthma subject to length and regularity of exposure.

PM2.5 – Particle sizes 2.5 microns and smaller (invisible to the naked eye) includes many industrial dusts such as lead dust, metallurgic dusts, wood dust, carbon black dust and coal flue gas. They tend to lodge in the bronchi, bronchioles and alveoli resulting in irreversible damage to the lungs which leads to lung cancer, silicosis and black lung disease.

>PM10 + PM10 + PM2.5 when suspended in the air are collectively known as total suspended particles (TSP)

>PM10 + PM10 + PM2.5 when settled out of the air are collectively known as deposited dust.

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Dangers of airborne dust contaminants.

Breathing in particle pollution can be harmful to your health. Coarse (bigger) particles, called PM10, can irritate your eyes, nose, and throat. Dust from roads, farms, dry riverbeds, construction sites, and mines are types of PM10. Fine (smaller) particles, called PM2.5, are more dangerous because they can get into the deeper parts of your lungs — or even into your blood. Particle pollution can affect anyone, but it bothers some people more than others.

People most likely to experience health effects caused by particle pollution include:
• People with heart or lung diseases (for example, asthma)
• Older adults
• Babies and children

If you have asthma, particle pollution can make your symptoms worse. Carefully follow your asthma management plan on days when pollution levels are high.

Particle pollution has also been linked to:
• Eye irritation
• Lung and throat irritation
• Trouble breathing
• Lung cancer
• Problems with babies at birth (for example, low birth weight)

If you have heart disease, breathing in particle pollution can cause serious problems like a heart attack. Symptoms include:
• Chest pain or tightness
• Fast heartbeat
• Feeling out of breath

A way forward
Long-term exposure to PM can have severe adverse impact on health, as it increases the age-specific mortality risk, particularly from cardiovascular causes. It can also trigger or exacerbate respiratory problems such as asthma or chronic bronchitis. Short-term health effects include irritation in the eyes, nose and throat, coughing, sneezing and shortness of breath. By the end of this article, we hope you know what airborne dust contaminants are, their types and different particle sizes with strong understanding of the ensuing danger to human that arises from exposure to them. Airborne dust contaminants must be eliminated at the source and GRT commits to finding feasible solutions through their innovatory chemical dust control palliatives to end dust at its source.

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REFERENCES

Dying benchtop workers lodge silicosis claims prompting urgent health warming. Retrieved 08/05/21

Immediate action required to prevent exposure to silica for engineered stone benchtop workers. Retrieved 08/05/21

Jang, H., and Topal, E. 2020. Transformation of the Australian mining industry and future prospects. Mining Technology: Transactions of the Institutions of Mining and Metallurgy.

Miners act on unacceptable dust exposures. Retrieved 08/05/21

Queensland Resources Council-Air Quality Retrieved 08/05/21