The best ways to measure decibels and sound intensity

Decibels are the measurement used to describe the intensity of sound. Broadly speaking, decibels are effectively a base ten logarithmic unit and consequently increasing the volume of sound by ten decibels would mean you would be exposed to a noise with a base sound that is twice as loud.
Measuring sound intensity and decibel levels is common, particularly in working environments in which standards have to be in place in order for employers to comply with laws and regulation involving noise intensity and exposure. 
Decibel measurement
Decibel levels and sound intensity can be measured by a number of ways. One of the most common and popular ways to measure decibel levels is with sound level meters.
What’s great about these specifically-designed decibel measurer devices is that, despite looking fairly simple and being straightforward to use, they provide an accurate decibel measurement of the levels of sound be produced in a given area.
Whilst sound level meters vary in complexity and capabilities they all share similar characteristics of comprising of a meter and electronic circuits which measure the sound that is detected by the device’s microphone. The sound data that the noise level meter picks up is then shown on a display, typically on a digital LCD display. Sound level meters can often be referred to as decibel meters or a noise dosimeters. 
Comparison charts
Depending on why you are wanting to carry out decibel measures, you may want to use another way to gather decibel levels data, which might not be as accurate as using a professional sound level meter but is less expensive and can be less time consuming using a decibel level comparison chart.
Such charts will give you a general overview of the amount of decibels produced by commonly heard noise and sound. Specifically designed decibel noise comparison charts are also likely to comprise of a column which states the potential health effects of a given sound.

For example, a decibel comparison chart may start with silence, which creates zero decibels and being exposed to silence has no potential risks to our health. The chart would then map out different sounds, going from the ‘quietest’ sound produced such as silence, breathing, whispering and libraries, moving through to louder sounds, such as TVs, highway traffic and food processors, right up to very loud sounds like a jackhammer, rock concert, steel mill, chainsaw and aircrafts taking off.
The chart would inform of the general decibel levels and decibel measures of such sounds. For example, a food processor is likely to produce 80 decibels of noise, which could potentially cause hearing damage after lengthy and consistent exposure. A jackhammer creates 100 decibels of noise, which could result in serious hearing damage following lengthy exposure. One of the loudest noises, an aircraft taking off, produces between 130 and 150 decibels of noise, which could have the potential of causes immediately hearing loss or eardrum rupture.

However, whilst such charts are useful as ‘quick reference’ guides, if you are wanting an accurate decibel measure, using a noise level meter as a decibel measurer will give you a much clearer reading of the decibel levels being created in a given environment.