The speed of sound in air has really nothing to do with the sea level and its atmospheric pressure.
Speed of sound is dependent on the temperature.
Look at the link: "Speed of Sound in Air and the effective Temperature".
Sea level.
At sea level, air has a density of approximately 1.2 kg/m3.
The higher the elevation the lower the air pressure. Sea level is considered the standard for air pressure measurement.
As you go above the sea level, pressure of air decreases.Atmospheric pressure at sea level is 1 atm.On top of mountain, air is thin which suggests less atmospheric pressure at that place.
Usually we talk about speed of sound. Speed is the rate of change of distance with time. Velocity is a measure of both speed and direction of a moving object. Velocity is the rate of change of displacement with time. Speed is a distance an object goes, velocity is measurment of speed AND direction. Speed of sound at 20 degrees Celsius (68 degrees Fahrenheit) is 343 meters per second.
The velocity of sound in air at sea level at normal temperature and pressure is 3.4329 metres/second.
Do you mean speed of sound at sea level? Scroll down to related links and look at "Speed of sound - temperature matters, not air pressure".
sea level
The air pressure is greatest at sea level.
Below sea level atmospheric pressure increases with depth. Air pressure at sea level is about 14.7 psia. Air pressure below sea level would be slightly higher.
Sea level pressure, sometimes as mean sea level pressure.
Sea level
At sea level
Sea level pressure.
About 186,000 miles per second at sea level.
It is not, air pressure is greatest at sea level. This is because the air pressure is caused by the weight of the air above you and at sea level the depth of the air column above you is at its maximum.
The air pressure must be higher in a valley below "sea level". The air mass above this point is more than at sea level.