The Composition of Inhaled and Exhaled Air. What Should and Shouldn’t Contain?

While air pollution remains an incredibly pressing topic in the twenty-first century, many still fail to realise the true scope of the problem. This is partly due to a lack of understanding about the composition of inhaled and exhaled air—what it contains and what it should (and shouldn’t) contain. In today’s article, we tackle this very important topic and clear things up once and for all.

What Is the Air, Actually?

To start us off, what is the air? In basic terms, the air is a mixture of gases and aerosols that collectively make up the Earth’s atmosphere. However, the chemical composition of air hasn’t remained static throughout our planet’s history, and in fact, has seen considerable changes over time.

In the present day, the current composition of exhaled air is standardised across the whole globe. While the concentration of individual air components still changes slightly depending on numerous factors, these changes are very minor. Of course, there are components in the air that can be called constants and those that can be called variables – the latter depend on various circumstances, hence their greater fluctuations, such as changes in the concentrations of carbon dioxide, water vapour, or sulphur dioxide.

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What Is Our Air Made Of?

So, what is the actual composition of the air? Below, you will find a comprehensive breakdown of its constituent elements:

• Nitrogen
• Oxygen
• Argon
• Carbon dioxide
• Neon
• Helium
• Methane
• Krypton
• Hydrogen
• Xenon

While the above list encompasses the primary components, the air also contains distinguishable mineral and organic suspensions. Among these are particulate matter and plant spores. These microscopic elements play a role in ecological processes and, under certain conditions, can influence air quality.

What Are the Differences Between Inhaled and Exhaled Air?

Due to biological processes, the compositions of exhaled and inhaled air differ slightly. This primarily affects the percentages of individual components.

For example, notice the differing percentage of oxygen in exhaled and inhaled air:

Inhaled air contents:

• Nitrogen – 78%
• Oxygen – 21%
• Other gases – 1%
• Carbon dioxide – 0.04%.

Exhaled air contents:

• Nitrogen – 78%
• Oxygen – 17%
• Carbon dioxide – 4%
• Other gases – 1%.

Inhaled and Exhaled Air – What Should It Not Contain?

Unfortunately, because of problematic air pollution present in many cities, the air in those places around the world contains elements that should not be there. Due to improper (or lacking) emission control measures, various types of particulate matter and harmful pollutants remain in the air under favourable weather conditions.

The biggest offenders usually come in the following forms:

• Factory smoke stacks
• A high number of car traffic
• Coal furnaces
• Waste burning
• Other sources of emissions (aviation, agriculture, power plants, wildfires etc.)

While the specific chemical breakdown of the various pollutants will depend on the prevalence of the above factors in a given city or region, per its most generally applicable definition, smog is understood to contain high concentrations of the following substances:

• Sulphur dioxide
• Nitrogen dioxide
• Carbon monoxide
• Benzene
• Ozone
• PM2.5
• PM10, which also can contain heavy metals like lead, arsenic, nickel, cadmium and benzo(a)pyrene—a chemical compound made of carbon and hydrogen.

All these pollutants exert negative effects on animals and humans alike. They make their way into our respiratory systems and can wreak havoc, causing damage to cardiovascular and pulmonary health, leading to complications such as

• Cardiac arrhythmia
• Hypertension
• Sudden cardiac arrest
• Cancer

That being said, pollutants also accumulate indoors, meaning it’s important to monitor air quality both indoor and outdoor. While a basic test checks carbon dioxide levels, a more accurate assessment considers multiple factors. Knowing the air composition is essential, especially when deciding if an area is suitable for permanent living.

The Takeaway

While inhaled and exhaled air differ slightly in their composition, high concentrations of pollutants should never be found in either. The effects on our health are drastic and should not be ignored. See how Airly is leading the fight against air pollution by checking out our case studies and reading up on how we partner up with renowned brands like Decathlon to spread public awareness.

Author

Marcin Gnat – PR and communication expert at Airly. Devoutly dedicated to the fight for clean air around the world. Fan of music, football, good food, and books.