Context: In response to deteriorating air quality in Delhi, the Government has boosted public transport and used suppressants to control dust.
About Dust Suppressants
- Dust suppressants are substances that are used to control dust emissions from various sources such as construction sites and roads.
- They can be salts of calcium or magnesium that can absorb moisture, or other chemical mixtures.
Types of Dust Control measures
- Water: Water is one of the most common and effective dust suppressants. It can be applied as a fine mist, spray, or through irrigation systems to dampen surfaces and keep dust particles from becoming airborne. Water is environmentally friendly and readily available.
- Chemical Dust Suppressants: Chemical dust suppressants are substances that are applied to surfaces to control dust. Common chemical suppressants include:
- Calcium Chloride: It is often used on roads and construction sites to control dust. It attracts moisture from the air, keeping the road or area damp and dust-free.
- Magnesium Chloride: Like calcium chloride, magnesium chloride is used for dust control on roads and surfaces. It is less corrosive to metals than calcium chloride.
- Lignin Sulfonate: Lignin sulfonate is a natural biopolymer that can be used as a dust suppressant, particularly in areas where ecological concerns are a priority.
- Synthetic Polymers: Synthetic polymers, like polyvinyl acetate or polyvinyl alcohol, can be applied to the surface to create a dust-retaining film.
- Soil Stabilizers: They are used to bind the soil particles together and prevent them from becoming airborne.
- Dust Control Equipment: Dust control equipment, such as dust collectors, electrostatic precipitators, and baghouses, are used in industrial settings to capture and collect dust particles before they can escape into the air.
- Vegetation: Planting vegetation in and around dusty areas can help reduce dust by stabilizing the soil and acting as a natural dust suppressant.
- Windbreaks: Installing windbreaks, such as walls or fences, can help reduce the movement of windborne dust by blocking the wind’s force.
Effectiveness of Dust Suppressants
- According to the Central Pollution control board, the use of dust suppressants along with water is relatively more effective in controlling pollution than conventional methods of dust control i.e., water spraying.
- With the use of dust suppressants, there is about a 30% reduction in dust concentration (PM 10, PM 2.5, and PM 1) within the first six hours on both construction sites and roads.
- Dust suppressants with bio-additives help to reduce dust for 5-6 hours as compared to plain water which lasts for 15-30 minutes.
- According to the Centre for Science and Environment, the duration of effectiveness of mixed dust suppressants is uncertain, and it is still unknown whether they have long-term effects.