The five types of white cells and the approximate percentage they make up in the blood are: 1  Neutrophils (55% to 70%) 2  Band neutrophils (0% to 3%) 3  Lymphocytes (20% to 40%) 4  Monocytes (2% to 8%) 5  Eosinophils (1% to 4%) 6  Basophils (0.5% to 1%)
A sound level meter is an instrument that can measure sound level, commonly used in noise pollution studies for the quantification of different kinds of noise, especially for industrial, environmental and aircraft noise. common variant of the sound level meter is a noise dosemeter (dosimeter in American English). However, this is now formally known as a personal sound exposure meter (PSEM) and has its own International standard IEC 61252:1993.
The human ear responds more to frequencies between 500 Hz and 8 kHz and is less sensitive to very low-pitch or high-pitch noises. The frequency weightings used in sound level meters are often related to the response of the human ear, to ensure that the meter is measuring pretty much what you actually hear. It is extremely important that sound level measurements are made using the correct frequency weighting - usually A-weighting.