Question

4.     Explain how following measurements are made. Please mention equipment used during those measures.

a.      Air quality

b.     Wind speed

c.      Carbon Monoxide

d.     Sound level

e.      Personal noise exposure

f.      Vibration

Answer 1

a. Air quality

The Air Quality Index, or AQI, is used to measure air quality. The AQI functions as a thermometer which runs from 0 to 500 degrees. Instead of showing temperature changes, though, the AQI is a way to show changes in the amount of air pollution. In order to understand the quality of air , it is expressed as numerical values. the values may range from 0 to 500.a low AQI value means the air is less polluted.Very high AQI values close to 500 shows that the air quality is hazardous.

there are a lot of digital sensing devices to measure air quality.

b.Wind Speed

wind speed is basically measured using an anemometer.It usually has four cups which are attached to a central axis through separate arms.When wind pushes these cups they rotate thereby rotating the axis. This rotation speed of axis will be proportional to the wind speed.

c.CO

carbon monoxide is measured using a system calls PPM(parts per million). For example, 100 PPM CO means that for every 999,900 molecules of air, there are 100 molecules of CO.Devices used for this are usually called as gas analysers. They can sense the count of CO particles in atmosphere.

d.Sound level

a decibel meter is used to measure sound levels.Sound travel as waves by creating lower and higher pressure areas in the air or any ,medium. Decibel meters sense this pressure and show the sound level.

e.Personal noise exposure

here also, the sound pressure level is measured using various techniques and deices. Dosimeter is one of the most preferred devices  for this purpose.

A noise dosimeter is a small , light tool that clips to the belt of a person with a small microphone that connects to the collar of the person close to an ear. The dosimeter stores information on the noise level, and performs an average operation.

f.vibration

Vibration measuring is usually done by using accelerometer which is a piezoelectric sensor.A piezoelectric material has a property to produce electrical voltage when a mechanical pressure is applied on it.So vibrations can be converted into electrical signals and it can be sensed in digital format.