How to remove high concentration of particles in metal industry

Created Wednesday, 11 August 2021


We breathe every four seconds, a total of about 22 000 times a day. In urban centers, where the air is highly polluted, each breath contains more than 25 million particles. On the other hand, indoor air quality may even be 50 times more polluted than outdoor air. We breathe fine dust, harmful gases, viruses, and bacteria and are also exposed to numerous other health-threatening particles and pollutants in the material and metal processing industry.

Where do all these air pollutants come from?

Sources of air pollution - Air pollution has a number of natural sources and particles from natural sources are usually larger in size. Their sources include pollen, sand storms, forest fires, and volcanoes. Sources from human activity produce numerous very small particles in the air. They arise especially in combustion processes caused by vehicles, power plants, construction sites, and the processing industry. There are also other particles caused by people's activities inside the buildings. These include textile dust, particles released from the skin, particles and aerosols released from copiers, the burning of wood, coal, and candles.

Read more about indoor air pollutants here.

The most dangerous particles

The most significant health risk factor is the inhalation of the smallest and most dangerous PM1 particle size (<1 µm and smaller). It consists mostly of nanoparticles and other smaller particles. Most PM1 particles come from incomplete combustion processes. They may enter the blood circulation and contribute to deadly diseases like heart attack, lung cancer, dementia, emphysema, edema, and other serious diseases, leading to shortened lifetime. 


How polluted is indoor air in the metal industry

We often measure very high concentrations of fine particles in the metal industry, which considerably exceed WHO recommended values in big cities, like Beijing. They are often several times over the recommendations made by the WHO and the EU for good indoor air quality. Welding, grinding and laser/plasma cutting processes produce huge amounts of fine PM1 particles and various gases that cannot be removed from the indoor air by ventilation alone. These processes require efficient dust extraction equipment with a sufficient degree of filtration, which means the use of HEPA H13 final filter when air is recirculated. In some cases, molecular filtration for harmful gases can be beneficial as well. Many countries have legislation saying employees working in metal fabrication must be tested frequently. Often only nickel and chrome are measured but all the PM1 particles can be harmful to the health and wellness of the employees.







Nitrogen Dioxide

Combustion processes, e.g. welding and cutting

Bronchial inflammatory symptoms in people and lowered lung function

Ground Level Ozone

Industrial emissions, particularly in welding, exhaust gases, petrol vapours, and chemical solvents Chest pain, cough, throat irritation, and stuffiness, worsened asthma and other lung diseases

Sulphur Dioxide

Combustion of fossil fuels Respiratory tract and asthma increase, headache and generally poor health

Heavy metals - arsenic, chromium, cadmium, lead, mercury, and nickel

Combustion processes, e.g. welding and cutting Damage to blood, heart, liver, kidneys, and other organs, as well as reproductive and respiratory organs, slowing mental development, allergic skin reactions

Camfil has many solutions for the material and metal processing industry

In most cases, dust and small particles can be extracted directly from the source by using accessories like extraction arms, canopy hoods, suction panels, etc. Because the dust load is big, the filter unit itself must have an automatic filter cleaning system that pulses collected dust layer off from the filter surface and drops it to the bin below the unit. Camfil has the widest unit selection in the market, as for example Camfil APC Gold Series X-Flo, covering also ATEX requirements in explosive dust applications.

When welding big components in the middle of the floor, direct source extraction is not possible. Then welding fumes can be handled by a system called Push/Pull. In that case, there is one ducting on the wall which removes dirty air (Pull) and leads it to the filter unit. An efficient filtration level with HEPA H13 separates also small particles and clean air is blown back to the hall with help of its own ducting (Push). Because air is recirculated there is no problem with air pressure balance and the system saves a lot of heating energy, too. 

If fume or dust load in production is not very high, then one solution is CamCleaner 6000, a standalone air cleaner. It has not automatic filter cleaning system but a big filter surface area in several stages with final filter HEPA H13. This air cleaner covers a large area and collects small particles efficiently from the breathing zone, especially when placed on the floor, not to the high ceiling.

Camfil provides solutions for both ventilation filtration and industrial contaminant management, as well as measurement services for air quality monitoring.

*Report references, links, and additional information and figures are available here.
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