Noise barriers are to mitigate highway noise pollution:

Noise barriers are to mitigate highway noise pollution:

High level noise is a disturbance to the human environment. Because of urbanization, noise in all areas in a city has increased considerably. One of the most pervasive sources of noise in our environment today is those associated with transportation. People reside adjacent to highways, are subjected to high level of noise produced by trucks and vehicles pass on the highways. Prolonged exposure to high level of noise is very much harmful to the health of mankind.

Artificial noise barriers are solid obstructions built between the highway and the residential areas along a highway. They block major portion of noise produced by passing vehicles on a highway. Effective noise barriers typically reduce noise levels by as much as half or more. The construction of noise barrier may be built in the form of earth mounds, vertical wall along the highways for creation of blockage of sound generated by heavy vehicles. The effectiveness of mitigation of sound depends upon the height of the mounds or walls. Function of noise barriers are: (1) it can reduce the loudness of traffic noise by as much as half; (2) It may not completely block all traffic noise, but gives certain relief to the residents; (3) It may be effective, regardless of the material used; (4) It must be tall and long with no openings for making it more effective; (5) It must be designed to be visually appealing looking into the aesthetic value of the site.

Apart from constructing artificial noise barriers, creation of greenbelt, by plantation of trees along the highways. The space between the residences and highways may be utilized for creation of greenbelt. As more and more noise pollution problem is being cropped-up, city planners are increasingly adopting various methods to

Control of Air pollution by controlling Particulate Matters

Airborne Particulate Matters (PM) - Pollution Prevention and Control:

Airborne particulate matters (PM) emissions can be minimized by pollution prevention and emission control measures. Prevention, which is frequently more cost-effective than control, should be emphasized. Special attention should be given to mitigate the effects, where toxics associated with particulate emissions may pose a significant environmental risk.

Measures such as improved process design, operation, maintenance, housekeeping, and other management practices can reduce emissions. By improving combustion efficiency in Diesel engines, generation of particulate matters can be significantly reduced. Proper fuel-firing practices and
combustion zone configuration, along with an adequate amount of excess air, can achieve lower PICs (products of incomplete combustion). Few following steps should be adhered to control PM:

1. Choosing cleaner fuels - Natural gas used as fuel emits negligible amounts of particulate matter.

2. Low-ash fossil fuels contain less noncombustible, ash-forming mineral matter and thus generate lower levels of particulate emissions.

3. Reduction of ash by coal cleaning reduces the generation of Particulate Matter (PM) emissions.

4. The use of more efficient technologies or process changes can reduce PIC emissions.

5. Advanced coal combustion technologies such as coal gasification and fluidized-bed combustion are examples of cleaner processes that may lower PICs by approximately 10%.

6. A variety of particulate removal technologies, are available – these are (a) Inertial or impingement separators, (b) Electrostatic precipitators (ESPs) , (c) Filters and dust collectors (baghouses), (d) Wet scrubbers that rely on a liquid spray to remove dust particles from a gas stream.

The principal methods for controlling the release of particulate matter are summarized here.

• Identify measures for improving operating and management practices.

• Consider alternative fuels such as gas instead of coal.

• Consider fuel-cleaning options such as coal washing, which can reduce ash content by up to 40%.

• Consider alternative production processes and technologies, such as fluidized bed combustion, that result in reduced PM emissions.

• Select optimal particulate removal devices such as ESPs and Baghouses.

Air pollution by Particulate matters (Fine and Coarse Dust particles):

Air pollution by Particulate matters (Fine and Coarse Dust particles):

‘Fine particles’ are less than 2.5 micron in size and require electron microscope for detection, however, they are much larger than the molecules of Ozone etc., and other gaseous pollutants, which are thousands times smaller and cannot be seen through even electron microscope.

Fine particles are formed by the condensation of molecules into solid or liquid droplets, whereas larger particles are mostly formed by mechanical breakdown of material or crushing of minerals. ‘Coarse particles’ are between 2.5 to 10 micron size, and cannot penetrate as readily as of Fine particle; however, it has been seen these are responsible for serious health hazards. The severity of the health hazards vary with the chemical nature of the particles.

The inhalation of particles has been linked with illness and deaths from heart and lung disease as a result of both short- and long-term exposures. People with heart and lung disease may experience chest pain, shortness of breath, fatigue etc., when exposed to particulate-matter pollutants. Inhalation of particulate matter can increase susceptibility to respiratory infections such as Asthma, Chronic Bronchitis. The general medical term given for such lung diseases is ‘Pneumoconiosis’.

Emissions from diesel-fuel combustion in vehicles / engines / equipments; Dusts from cement plants, power plants, chemical plants, mines are a special problem, specially for those individuals breathing in close proximity to such atmosphere. Cars, trucks and off-road engines emit more than half a million tones of diesel particulate matter per year.