The Dangers of High Carbon Dioxide (CO2) Levels

Although carbon dioxide (CO2) is a byproduct of many natural processes, high levels of CO2 can cause a variety of health effects on humans. In this article, we explain at what levels CO2 becomes dangerous and the negative health effects of these high CO2 levels. Also, how do CO2 levels become high in the first place?

How Carbon Dioxide (CO2) Levels Become High

Carbon dioxide (CO2) gas is produced by both natural processes (respiration, volcanoes) and human activity (fossil fuels/deforestation). Indoor spaces are more at risk of high CO2 levels due to the lack of fresh air. Fresh air helps dilute high concentrations of CO2. 

Indoor spaces are at risk of high CO2 levels when large amounts of people occupy spaces that are small or have poor ventilation. This is because the CO2 produced through respiration by the occupants builds up over time and has nowhere to go.

Dangers of high CO2 levels
Humans are CO2 spewing machines

Even larger spaces such as grocery stores can have higher CO2 levels with enough occupants.

CO2 monitor in grocery story

Homes can also be at risk when CO2 levels in the soil below are high and the gas seeps through the cracks in the basement floor and foundation. 

Carbon dioxide levels typically are not a concern outside but can reach dangerous levels during a volcanic eruption. Volcanoes emit large amounts of CO2 during eruptions.

The Danger of Cabon Dioxide to Humans

Unlike dangerous PM2.5 pollution, low levels of CO2 are not dangerous. But at high levels, the CO2 can displace oxygen resulting in a variety of negative effects on humans.

Typical outdoor carbon dioxide levels range from 350-450 ppm (parts per million). But carbon dioxide will build up if people are in an enclosed, unventilated room.

At moderate levels, CO2 makes people tired, affects cognitive skills, and causes headaches. Studies show even moderate increases in CO2 levels from 600 ppm to 1000ppm decrease cognitive ability and decision making.

At very high levels, CO2 can make people sick or even die.

Health effects of different CO2 concentration levels

Using CO2 Monitors to Test CO2 Levels

To ensure CO2 levels do not reach dangerous levels in crowded areas, a CO2 monitor can be used. At Smart Air, we have tested the accuracy of two of the most popular CO2 monitors on the market. Our tests indicate that the monitors likely track true CO2 levels quite closely.

Using a monitor to test CO2 levels

Bottom Line: When Do CO2 Levels Become Dangerous and What are the Health Effects?

Studies show even moderate increases in CO2 levels from 600 ppm to 1000ppm decrease cognitive ability and decision making. CO2 levels of 5000ppm can cause headaches, and levels of 70000ppm can kill you.

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