Do you live under the CO2 Dome?

Daniel Lux
The Startup
Published in
5 min readJun 25, 2019


Many towns are in the danger zone!

Illustration of a CO2 dome

As depicted in the illustration above, we can sometimes experience conditions with highly increased levels of CO2 in the atmosphere. This occurs in certain weather conditions, where there is little wind combined with the lack of rain. The air is not well circulated, and thus the exchange with cleaner air does not happen. These are the same conditions that also cause what we call smog. Some towns are more in danger of such domes. Towns that are located in a valley have a higher risk of bad air, as their location acts as a bowl where air pollution can be collected. Towns where hills shield from the wind are also at risk.

Since CO2 is one of the heaviest components of our atmosphere, CO2 will stay close to the earth’s surface, forming a so-called CO2 dome. In Paris, for example, already today the atmosphere can sometimes reach levels of CO2 of 950 ppm (parts per million). This is more than twice the normal atmospheric level of CO2 in the atmosphere, which is currently a bit above 400 ppm.

Surprisingly, CO2 is only measured in very few places on our planet, and rarely in real time. This is due to some unfortunate circumstances where:

  1. CO2 is considered a natural part of the atmosphere
  2. CO2 levels are actually difficult to measure accurately
  3. CO2 is not toxic

Due to all of the above, CO2 was not included in the standard set of required measurements for meteorology as defined by the World Meteorological Organization (WMO).

Try to take a look at the “Air Quality Index” (AQI).

AQI Category, Pollutants and Health Breakpoints. Source: Wikipedia

Notice something?

CO2 is not one of the components that are measured.

Searching the internet, one quickly finds that local CO2 measurements are not as widely available as the measurements in the AQI.

More detailed measurement and more widely and openly available data would, however, enable us to analyse the impact of CO2 levels on our daily life. Just like a study by the National Bureau of Economic Research found that temperatures have an effect on learning and test results, scientists could use statistical methods to analyse the effect of CO2, if data were available.

For example, some of the following questions could be answered:

  • Is there a correlation between illnesses and CO2?
  • Is there a correlation between test results in schools and CO2?
  • Is there a correlation between economic output and CO2?

CO2 has an effect on our health and intelligence

Most of us have experienced being in a badly ventilated room. After some time, you start to feel tired, and in extreme cases we might even get a headache. There has been research that suggests a relationship between increased CO2 levels and decreased cognitive capabilities. Since indoors CO2 levels are relatively higher than outdoors CO2 levels, the effect of a CO2 dome is even stronger indoors.

I have written another article, where I sum up the effect of increased CO2 levels by comparing the effects on the body to the effect of alcohol. Fortunately the really severe effects only materialize at very high CO2 concentrations. From my investigations, however, I found out that there are grey spots in our knowledge where it comes to long-term effects and effects on children when growing up in environments with increased CO2 levels.

Does CO2 harm your body?

Higher outdoor CO2 levels result in increased energy usage

Next to the more abstract questions that can be researched, there are also more direct consequences that arise from a higher atmospheric CO2 level. The current limit, that many ventilation systems for buildings are set to, is 1000 ppm. So when the level of CO2, measured indoors, increases above 1000 ppm, the ventilation system will start to circulate air. The higher the level of CO2 is in the outside air, the more air will need to be circulated to get the indoor air below 1000 ppm. In the case where the outside air might actually reach 1000 ppm, the ventilation system would never stop, even if there are no people in the building and the air therefore wouldn’t need to be exchanged.

Some increased CO2 levels are also just temporary. Take the example of a building next to a road with heavy rush hour traffic. During the rush hour, the CO2 level might increase dramatically, causing the ventilation system to use extra energy. If the same building were ventilated before the rush hour, and then again after, the inside air quality would end up being better overall, while the system would still have used less energy.

More measurements and data would enable connected ventilation systems to optimize the timing of the ventilation cycles which would result in reduced energy usage. Since energy has a cost, this means that having CO2 data available can be turned into a business opportunity.

Do domes of fresh air also exist?

CO2 domes are created due to certain weather conditions. But what if these weather conditions were present in areas where there were a lot of woods and little human activity? Would the CO2 level be lower in such areas?

Today we don’t know, as we do not have enough measurement points.

I would certainly like to know if such locations exist. Wouldn’t that make a good destination for a next vacation with the family?

Let’s start measuring!

In order to understand and potentially mitigate the effects that increased levels of CO2 most likely have, we have to start measuring the stuff, more fine grained and more widespread.

There are numerous open source hardware and software projects measuring air quality already today. It would be great if these projects were to include CO2 sensors as well, not only carbon monoxide, micro particles, NOx and the like.

There are also business opportunities in this type of data. We will be able to save energy on ventilation systems, and tourism can use this information for making destinations more attractive.


Composition of the atmosphere, scientific details

Widory, D. and Javoy, M. 2003. The carbon isotope composition of atmospheric CO2 in Paris. Earth and Planetary Science Letters 215: 289–298.

Air Quality Index AQI

Temperature affects learning and test results

Does CO2 harm your body?

Associations of Cognitive Function Scores with Carbon Dioxide, Ventilation, and Volatile Organic Compound Exposures in Office Workers: A Controlled Exposure Study of Green and Conventional Office Environments



Daniel Lux
The Startup

What scares me about climate change is the effect that high CO2 levels have on our bodies and intelligence, yet very few are writing about this.