What is the partial pressure of nitrogen at 135 feet of seawater (fsw)?

To determine the partial pressure of nitrogen at 135 feet of seawater, it is essential to understand the relationship between depth and pressure in a diving environment.

At sea level, the ambient pressure is approximately 1 ATA (atmosphere absolute). As you descend underwater, the pressure increases by approximately 1 ATA for every 33 feet of seawater due to the weight of the water above you. Therefore, the total pressure at 135 feet can be calculated as follows:

1. Calculate the pressure at depth:

• The depth, 135 feet, includes the atmospheric pressure at the surface.

• For the first 33 feet, add 1 ATA for each additional 33 feet of seawater. In this case:

• 135 feet / 33 feet per ATA = 4.09 ATA (rounded)

• However, since we start counting the first atmosphere at the surface, we add 1 ATA for atmospheric pressure:

• Total pressure = 1 ATA (surface) + 4.09 ATA = 5.09 ATA.

2. Now, to find the partial pressure of nitrogen (N2), we need to consider that nitrogen makes up about 79% of the atmosphere. Therefore, the