What is the Best Type of Outdoor Dust Suppression?

Published by Giles Bennett

on Monday 21 November 2022

Last updated on Friday 12 April 2024

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What is the Best Type of Outdoor Dust Suppression?

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As anyone who has been tasked with it knows, selecting the best type of dust suppression for your outdoor site can be like navigating a minefield. This article is designed to help you clear the fog (pun intended) and get a better grasp of the different methods that are in common use, as well as understand the advantages and drawbacks of each.

Firstly, it helps to understand the different types of dust suppression that are out there. These can be broadly split into four categories, namely:

Installed water- or foam-based dust suppression systems (misting systems that produce a fine mist, sprinkler systems that produce a coarse water jet, or foam systems that produce a spray-on foam)
Plug-in mobile water-based dust suppression units (portable units with a cannon or jet for dispersing water mist or spray, which need to be connected to a power and/or water supply)
Self-contained mobile water-based dust suppression units (towable bowsers with a cannon or jet for dispersing water mist or spray and powered by an onboard generator or battery, or simply bowsers with a gravity-fed splash-plate or similar for wetting unmade surfaces)
Topical or surface treatments (liquid or powdered products that can be applied to the ground or stockpiles to seal surfaces or weigh down dust particles, which helps prevent dust release over a more extended period than water alone)

To determine the right solution for you, there’s a series of questions you need to answer - let’s guide you through that thought process:

Is the dust source static or does it change location? If the source of dust emissions is likely to remain in the same location for an extended period of time, e.g. from an installed processing plant or permanent haul road, then investment in an installed system or topical treatment of the dusty surface will most likely be a cost-effective solution. However, if the dust emissions are from a changing location (e.g. different workfaces on a construction site), then a mobile water-based dust suppression unit may be more cost-effective because it can be deployed only when and where required.
Is water available near to the dust source? All water and foam dust suppression systems require a reliable water supply, normally to potable standards. If an adequate water supply is not available near to the dust source then your options will be limited to either topical treatments or mobile water-based dust suppression units which have an onboard supply of water, which will need regular topping up.
Is power available near to the dust source? Most water and foam dust suppression systems require power to supply pumps, fans and/or ancillary controls. If a suitable power supply is not available near to the dust source, then your options will be limited either to topical treatments or mobile water-based dust suppression units with their own onboard power source.
How long-term is the dust issue? If the source of the dust emissions is likely to remain in the same location for an extended period of time, e.g. from an installed processing plant or permanent haul road, then investment in an installed system or topical treatment of the dusty surface will most likely be a cost-effective solution. However, if the dust emissions are likely to be short-term, then a mobile water-based dust suppression solution may be more cost-effective because it can be deployed only when and where required, and it can even be hired in temporarily where the duration of use does not justify the cost of purchase.
How local is the dust source? Establishing how local or widespread the dust source is will help determine the solution required. Localised dust emissions are typically caused where material is agitated while it is being handled or processed, and water or foam suppression systems will typically work best to suppress the resultant dust as close to the source as possible. Dust emitted from a large surface area (e.g. multiple stockpiles, unmade haul roads or large expanses of exposed soil) will be less viably treated by using an installed system but instead may need treatment with a topical surface treatment or mobile dust suppression unit. With all dust suppression applications, it should be borne in mind that a cardinal principle of effective dust suppression is to prevent the escape of dust from as close to the dust source as possible - we talk more about this later in the article.

Next, you may find it helpful to review some of the key advantages and disadvantages of each type of solution. Here goes:

Solution Type	Advantage	Disadvantage
Installed Misting or Fogging System	Lower water consumption More efficient dispersal of mist = better coverage Smaller droplet sizes more likely to match dust particle size = more effective capture Surfactant-based dust suppressants can work well with this type of system, further increasing efficacy Electrically powered = greener credentials	The finer the mist, the more susceptible it becomes to wind movement Smaller droplets are more respirable, with a potential Legionellae risk if the water supply becomes contaminated Typically a higher investment cost than conventional sprinkler systems High water pressure on some system designs could present a safety risk
Installed Sprinkler or Rain Gun System	Typically a simple design and straightforward installation Often lower capex cost than more advanced misting technologies Typically electrically powered = 'greener' credentials	High water consumption = reduces 'green' credentials and higher running cost Excessive water output can lead to flooding, contaminated surface water run-off, surface erosion, increased vehicle tyre wear Larger droplet sizes less likely to match dust particle size = less effective capture
Installed Foam Suppression System	Lower water consumption Longer lasting effect Electrically powered = greener credentials	Typically very high operating costs due to foaming chemical requirements Foam can clog certain types of equipment Can be susceptible to wind movement Leaves chemical residue on treated material Typically higher investment cost Typically only suited to longer-term or permanent processing plants Will not treat airborne dust from other sources beyond the treated process
Mobile Dust Suppression Unit, Not Self-Contained	Can be moved around to suit dynamic operations = more flexible than an installed system Can be moved closer to dust source = more targeted suppression Units that utilize turbofan propulsion (e.g. MistCannon) usually have a greater scope of coverage than installed systems Some designs can be plugged into electrical mains = greener credentials Can be stowed away easily in winter minimizing risk of frost damage	Units with pumps or turbo fan propulsion require a power supply with trailing cables = trip hazard Units without an onboard water tank will require a water supply with trailing hoses = slip/trip hazard Units that utilize turbofan propulsion (e.g. MistCannon) have a higher noise level than installed systems
Mobile Dust Suppression Unit, Self-Contained	Totally portable = most flexible solution Can be moved close to dust source = targeted suppression No need for trailing cables or hoses = less slip/trip risk Units that utilize turbofan propulsion (e.g. MistCannon) usually have a greater scope of coverage than installed systems Can be stowed away easily in winter minimizing risk of frost damage	Most self-contained units with pumps and/or turbo fan propulsion typically use diesel = less 'green' than mains power (although HVO and battery-powered versions of some equipment are now available) Units need to be filled up with water periodically, often during an operational shift Units with engines and/or which utilize turbofan propulsion (e.g. MistCannon) typically have higher noise levels
Topical or Surface Treatment	Use of water reduced or in some cases (e.g. DustLess), eliminated altogether Typically such products give long-term effective control of surface dust, removing the need for resources to be tied up constantly with the use of water bowsers in dry weather Can be very cost-effective over an extended time period, when compared to the cumulative costs of conventional methods (water/power/labour resource) over the same period	Initial investment can be high compared to conventional methods May not be cost-effective if surface finish is short-term (e.g. changing haul route, dynamic stockpile)

Then finally, earlier in this article we said that we’d come back to the importance of treating dust close to its source.

The highest objective should always be to prevent dust emissions in the first place. Click here to read our article regarding ERIC PD. If this is not feasible, then suppressing dust as close to the source as possible will invariably make your job easier. Conversely, letting it first disperse far and wide makes it much harder to capture effectively. For the same reason that you wouldn’t start by hosing the outside walls of your house to extinguish a chip pan fire in your kitchen, neither should a perimeter spray system be viewed as the best way of controlling localized dust sources. It is far too late to contain the dust (or the fire for that matter) by the time that it has reached the perimeter, and you would be much better off stopping it getting there in the first place.

There is a perception in some quarters that perimeter water-based dust suppression systems are a 'catch-all', however the truth is quite the opposite. Dust being whipped up by the wind and blown towards the boundary will often be above and beyond the reach of a typical misting system. Furthermore, whatever proportion of the dust is caught by the system, the result is that dust-laden mist may then fall out on the wrong side of the boundary. Whilst this may not be an issue, it more likely will be, especially if you have a car showroom or supermarket next door!

We recognize that if dust is being generated across a broad tract of open land rather than from localized sources, it may seem a challenge to catch it anywhere other than at the boundary. This may be true, but this is where topical treatments as mentioned above can come into their own. A single application, at the start of the dry season, of a topical product such as DustLess, could conceivably solve your dust issue for the entirety of the season.

Having said all this, there are likely to be a handful of situations where no other option is feasible, and it may be necessary to deploy a perimeter water-based dust suppression system as a 'last-resort' or 'belt-and-braces' measure!

We trust this post has been helpful. As ever, no article of this nature can answer every question or conceive every scenario and our team of Environmental Solutions Consultants are always on hand to advise you on your particular site requirements.