Question

Which of the following measures can be taken to control noise pollution in our surroundings.
A) By using silencers in vehicles
B) Planting trees
C) Using noise mufflers
D) All of the above

Answer 1

Hint: High frequency signals are usually interpreted as being louder than low frequency signals with the same amplitude by those with natural ears. This is why electronic sound level metres for calculating noise level take the differences of perceived light with pitch into account. Frequency filtering in metres refers to the response of the human ear and the relative loudness of different sounds.

Complete step by step solution:
A sound attenuation, which is a decrease of sound volume, decreases the amount of noise emission. The energy dissipates sound over long distances before not much energy is left to vibrate air molecules. Natural attenuation takes place. Vegetation speeds up normal absorbent, deflective, refractive and mask attenuation processes.

Leaves, twigs and branches absorb the sound energy of trees, shrubs and herbaceous growth. Pressure waves are refracted as pressure hits vegetative walls and curves through plant structures. Vegetation makes masking noises like rustling leaves, roots and stalks. Wildlife sounds like birds and insects enticing urban veggies, as well as noise pollution by mask.

Precise sound measurements and empirical explanations vary from other subjective human sound impressions and beliefs. Both the pitch and the loudness of subjective human responses to sound. Through using silencers in cars, production equipment and home appliances, noise emissions can be minimised by reducing the use of car horns, low-volume TV, and radio and music systems. It is also beneficial to minimise noise emissions by planting trees near roads and houses.

Correct option is (D).

Note: An increased interval between source and receiver will go a long way to reducing the emission of noise by zoning noisy industrial districts, coach terminals and train stations, aerodromes, etc. from home areas. The residential areas, educational institutions and particularly the hospitals should be silent.