# Moisture Ratio in Air: Why Do Tables Stop at 50°C?

• Vector1962
In summary, moisture ratio in air is a measure of the amount of water vapor in the air compared to the maximum amount of water vapor that can be held at a certain temperature. Tables that show moisture ratio typically stop at 50°C because at this temperature, the air is considered to be fully saturated and can hold no more water vapor. This is known as the saturation point. Beyond this point, the air is unable to hold any additional moisture and it would start to condense into liquid form. Therefore, it is not necessary to go beyond 50°C in moisture ratio tables as it is the maximum capacity for water vapor in the air at that temperature.
Vector1962
Homework Statement
Why do moisture ratio tables related to temperature, humidity and dew point only go up to about 50 deg C?
Relevant Equations
N/A
Wondering why moisture ratio tables related to temperature and air only go up to roughly 50 C or so? is that temperature a "boundary" on the amount of water air can hold?

Vector1962 said:
Problem Statement: Why do moisture ratio tables related to temperature, humidity and dew point only go up to about 50 deg C?
Relevant Equations: N/A

Wondering why moisture ratio tables related to temperature and air only go up to roughly 50 C or so? is that temperature a "boundary" on the amount of water air can hold?
My guess is that since humidity and dew points are weather related, the graphs and tables would only display "Earthly" weather values.
According to my googling, a place called Dallol Ethiopia is the hottest location in the world:
Record high: 49°C​
Average high: 46.7°C​

I'm not sure why anyone but scientists would want to know what the values are above 50°C.
Given the linearity of the graph at wiki regarding Dew Points, without even doing any maths, my guess is that 50°C is not a boundary.
Guessing that 100°C might be considered a boundary though, at atmospheric pressure.

I appreciate your reply. I don't really consider myself a scientist but rather more curious concerning the values between 50C and 100C. Seems like with the amount of information currently available regarding water that the tables and graphs would routinely go to 100C . Don't suppose you have any idea where to get one?... maybe a CRC chem book?

Vector1962 said:
I appreciate your reply. I don't really consider myself a scientist but rather more curious concerning the values between 50C and 100C. Seems like with the amount of information currently available regarding water that the tables and graphs would routinely go to 100C . Don't suppose you have any idea where to get one?... maybe a CRC chem book?
This calculator seems to give similar results as my interpolation/eyeballing of the wiki dew point graph, up to 100°C.
(Within 4.1% of each other from 20 to 100% RH)

## What is moisture ratio in air?

Moisture ratio in air, also known as humidity ratio or specific humidity, is the amount of water vapor present in the air compared to the amount of dry air.

## Why do tables for moisture ratio in air stop at 50°C?

The tables for moisture ratio in air are based on the saturation point of water vapor in air. At 50°C, the air can hold the maximum amount of water vapor, making the tables unnecessary for higher temperatures.

## How is moisture ratio in air calculated?

Moisture ratio in air can be calculated using the following formula: MR = (m_w / m_d), where MR is the moisture ratio, m_w is the mass of water vapor, and m_d is the mass of dry air.

## What is the importance of knowing moisture ratio in air?

Moisture ratio in air is important in various industries, such as HVAC, agriculture, and food processing. It helps in determining the level of humidity and the potential for condensation, which can affect product quality and safety.

## How does temperature affect moisture ratio in air?

As temperature increases, the moisture holding capacity of air also increases. This means that at higher temperatures, air can hold more water vapor, resulting in a higher moisture ratio. However, at 100% humidity, the moisture ratio remains constant regardless of temperature.

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