Wet scrubbers are well suited for moist emissions and they efficiently remove particles as small as 0.5 m m. However, the sludge they produce is often hazardous, they can freeze during cold weather, they corrode, and they are more expensive due to greater pressure loss and the cost of waste disposal. The final removal mechanism is sieving which is important for the removal of submicron particles. Bag houses have high removal efficiencies over a broad range of particle sizes, flexibility in design, high volumetric capacities, reasonable pressure drops, and reasonable power requirements. However, they require large amounts of space, they can explode, and some exhaust streams may be detrimental to filter materials.
Electrostatic precipitators are the most efficient method for removing submicron particles.
The disadvantages of electrostatic precipitators include high installation costs and large space requirements. SOx is produced naturally by volcanoes and the degradation of organic matter. The primary anthropogenic source of SOx is the combustion of coal. SOx is the primary contributor to acid rain. SO 2 paralyzes the cilia which line the respiratory tract thus destroying on of our natural defense mechanisms against particulates.