what causes air pressure to change

What causes air pressure to change? Air pressure is a significant aspect of Earth’s atmosphere since it controls global wind and weather systems.

And it is clear that the air pressure does not remain the same everywhere. But, what many people do not know is the number of factors causing the pressure to change.

So, what causes air pressure in an area to change? Why is it important to keep an eye on those changes?

A change in temperature, altitude, weather systems, and human activities can cause air pressure to change in any particular area. 

More about Air Pressure and How to Measure It

how to measure air pressure

There is the air around you everywhere and it presses on everything all the time. And that pressure is called atmospheric or air pressure.

Millibars (mb) and inches of mercury (inHg) are the standard units for describing atmospheric pressure (inHg).

The average pressure of the atmosphere is about 1013 millibars (mb) (or 29.92 inHg) at sea level.

Fact: Isobars are lines used to depict air pressure on weather maps, and these lines connect regions with the same atmospheric pressure. 

Measuring Air Pressure in An Area

It is possible to measure air pressure in different ways. For instance, barometers are commonly used to measure atmospheric pressure.

It is important to note that barometers can be of different types, including:

  • Mercury-based barometer
  • Aneroid-based barometer
aneroid-based barometer

Let’s dig more about these two types of devices used to measure air pressure around you. 

Mercury Barometer

A mercury barometer is essentially an inverted glass tube submerged in a larger mercury-filled container.

A column of mercury in the tube rises above the container’s surface; its height is directly related to the pressure outside.

Barometric pressure, often known as the height of the mercury column, can be measured in either millimeters or inches. 

Aneroid Barometers

wall mounted aneroid barometer

Compared to mercury barometers, aneroid barometers are lighter and smaller.

An aneroid cell is a pressurized metal chamber that can expand and contract in response to variations in air pressure.

The pressure reading is shown on a dial through a mechanical indication linked to the aneroid cell.

In the fields of meteorology and aviation, aneroid barometers are a common tool. 

Additional Tools to Monitor Changing Air Pressure

The atmospheric pressure can be monitored with a variety of tools besides barometers.

A couple of more common ones include:

  • Pressure Transducers
  • Weather Balloons
monitoring air pressure of weather balloon

Electronic sensors known as pressure transducers can detect and convert variations in ambient pressure into an electrical output.

Barometers are just one of the many instruments that may be sent into the upper atmosphere on weather balloons.

These enormous balloons filled with helium or hydrogen are used to detect atmospheric pressure, temperature, and humidity.

Fact: Those areas of the atmosphere that have high pressure are called anticyclones, and those with low pressure are called cyclones or depressions. 

What Causes Air Pressure to Change?

earth atmosphere causes air pressure change

As mentioned already, the force produced by the weight of Earth’s atmosphere on Earth’s surface is known as air pressure or atmospheric pressure.

Alterations in atmospheric pressure can have far-reaching effects on both weather and human health.

Temperature, height, weather systems, and human activities are only a few of the variables that might affect the local air pressure. 


One of the most influential things that can alter atmospheric pressure is temperature.

Heat causes air to expand and lose density, leading to buoyancy. As a result, atmospheric pressure close to the surface of the planet drops.

When air is cooled, however, it contracts and its density increases, leading to the opposite effect with the air sinking. In turn, this causes atmospheric pressure to rise. 


Altitude is another contributor to shifts in atmospheric pressure. High altitudes have lower air pressure because the atmosphere’s weight reduces with height.

When you reach a mountain’s peak, for instance, the air pressure drops.

Altitude sickness, brought on by the reduced air pressure at higher heights, is a common problem for mountaineers and hikers. 

Weather Systems

Pressure shifts in the atmosphere can also be brought on by weather systems, including:

  • Tornadoes
  • Hurricanes
  • Thunderstorms
lightning and thunderstorm

Systems like these are distinguished by low-pressure regions that draw in surrounding air, forcing it to rise and condense, ultimately resulting in precipitation.

Pressure on Earth’s surface drops as air rises.

Conversely, high-pressure systems, where air sinks to the Earth’s surface and causes higher air pressure there, are associated with sunny skies and mild weather. 

Human Activities

Human actions can bring about changes in atmospheric pressure.

Large-scale industrial activities, including oil and gas drilling, can affect atmospheric pressure by releasing gases into the atmosphere.

The displacement of air by the construction equipment is another possible source of atmospheric pressure variations during massive construction projects like the construction of skyscrapers. 

Air Masses

confluence of air masses

When answering, “what causes atmospheric pressure to change?” you cannot ignore the role air masses play.

The term “air mass” refers to big clusters of air that share comparable conditions in terms of temperature and humidity.

If two masses of air with notably different temperatures and/or relative humidity come into contact, you are sure to notice a change in air pressure in that region.

This can happen when a cold front collides with a warm front and the cold air pushes the warmer air upward, causing a decrease in atmospheric pressure.

Fact: Clear weather is indicated by persistently high air pressure, while a drop in air pressure indicates deteriorating weather. 

Why Is It Important to Measure Change in Air Pressure?

There are several compelling reasons why it is essential to monitor atmospheric pressure.

It has important applications in meteorology, climatology, air quality monitoring, and industrial safety. 

Importance in Weather Forecast

Monitoring atmospheric pressure is a crucial component of modern weather prediction system.

Tracking shifts in air pressure can aid meteorologists in predicting shifts in temperature, humidity, and precipitation because of this close relationship.

importance in weather forecast

Predicting the development and path of weather systems like tropical storms and hurricanes is important to disaster planning and public safety.

And meteorologists can do this by tracking changes in air pressure over time. 

Importance in Regulating Air Quality

In congested metropolitan areas, air quality can be impacted by shifts in atmospheric pressure.

Certain low-pressure systems have the ability to trap pollutants close to the ground, which can reduce air quality and pose health hazards.

If environmental agencies monitor atmospheric pressure fluctuations, they can pinpoint potential hotspots for air quality problems and take corrective measures before they become serious.

Importance in Maintaining Health

Any shifts in atmospheric pressure can have negative effects on human health.

A variety of health issues, such as altitude sickness and hypoxia, can be the result of being at high altitudes where the air pressure is lower.

Therefore, keeping an eye on the air pressure is important for the well-being of those who live or work at high elevations.

Fact: Air pressure fluctuations affect several fields, including aircraft, oil and gas exploration, and scuba diving, and pressure measurements help keep their safety standards updated. 

What Would Happen If Air Pressure Stays the Same?

different weather systems

Global air circulation, the formation of weather systems, and the redistribution of heat and moisture over the planet are all dependent on atmospheric pressure.

It would have a major effect on weather, atmospheric circulation, and the viability of life on Earth if air pressure were constant everywhere.

Lack of mobility of air masses due to the constant pressure would lead to a uniform, boring weather. 

Leading to Disturbed Circulation Pattern

The air is always migrating from higher to lower altitudes as pressure differences around the globe fluctuate.

The trade winds, the jet stream, and the Hadley cells are all examples of atmospheric circulation patterns made possible by this flow. 

If atmospheric pressure were constant worldwide, there would be no reason for the air to circulate, leading to the collapse of the current system.

Disrupting Global Water Cycle

disrupting global water cycle

Water on Earth flows naturally from higher to lower pressure, an effect of the air around it.

It means oceans, rivers, and lakes would dry up if air pressure were the same everywhere.

Such a change would have far-reaching consequences for the global water cycle and the allocation of freshwater supplies.

Fact: The letters "H" and "L" on a weather map respectively denote areas of high and low pressure. 


What causes air pressure to change? Temperature, height, weather systems, human activities, and different air masses are all potential causes of a shift in air pressure.

By learning more about what triggers shifts in atmospheric pressure, we may better anticipate and prepare for weather events.

It may also help lessen the negative effects of human activities on the environment and gain a deeper familiarity with the workings of Earth’s atmosphere.