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Engineer and PhD Student Launch CO2 Breathing Emission Calculator 

Engineer and PhD Student Launch CO2 Breathing Emission Calculator 
20 July 2021 | Updated 21 July 2021

A PhD student and civil engineer have designed a CO2 measurement tool for indoor settings, based on their experiences of poor-quality air in offices.

Kenneth Alambra is a civil engineer with a passion for innovation, and, like millions of people, an office worker. After experiencing headaches due to clammy indoor air, full of exhaled CO2, he designed a tool to compute the room’s air quality based on how many people are in it throughout the workday.

Using the Omni Calculator Project framework, Alambra built the CO2 Breathing Emission Calculator with Dominik Czernia, a PhD student in physics.

Based on the type of room, the number of occupants, and the time they spend there, it calculates the CO2 concentration and shows the potentially negative effects.


CO₂ Breathing Emission Calculator



The Effects of CO2 on Indoor Air Quality 


The emission of carbon dioxide from human activity is a well-known threat to our planet and is often considered one of the main contributors to the greenhouse effect. However, Alambra and Czernia are primarily interested in what happens when you breathe in carbon dioxide.

Although the carbon dioxide levels in the outside air is still relatively low, the problem arises in closed spaces where people constantly exhale CO2 as a natural consequence of breathing. To investigate this problem, they decided to create the breathing emission calculator, which estimates whether the CO2 concentration in a room is at an acceptable level. It can then advise whether the room required additional ventilation.

Exposure to high CO2 concentrations may cause drowsiness, increased heart rate, blood pressure, unconsciousness, and even life-threatening complications. 

Although CO₂ gas is generally non-toxic for humans, it can be dangerous in excessive amounts for two reasons:


  1. Chemical - CO2 dissolves in the body's water, enters the bloodstream, forms carbonic acid, and eventually makes the blood acidic. That lowers the blood pH, and too low blood pH is dangerous for health. Interestingly, too low CO2 concentration results in elevated blood pH, which causes alkalosis, which is also a dangerous state.
  2. Mechanical - CO2 acts as an asphyxiant, a gas that displaces the normal oxygen in air. As a result, the oxygen content is reduced, which can lead to death by suffocation in extreme cases. What's more, CO2 is odourless, and we might not even notice if it's present in high concentrations.

The US Food Safety and Inspection Service prepared a health hazard information sheet for carbon dioxide, where you can find the following table describing symptoms of different levels of CO₂ exposure:


CO2 Concentration


< 10,000 PPM (1%)

Permissible exposure limit (for 8-hour exposure)

10,000 - 15,000 PPM (1% - 1.5%)  

Typically no effects, possible drowsiness

15,000 - 30,000 PPM (1.5% - 3%)

Mild respiratory stimulation for some people

30,000 - 40,000 PPM (3% - 4%)

Moderate respiratory stimulation, increased heart rate and blood pressure

40,000 - 50,000 PPM (4% - 5%)

Immediately dangerous to life or health

50,000 - 80,000 PPM (5% - 8%)

Strong respiratory stimulation, dizziness, confusion, headache, shortness of breath

> 80,000 PPM (8.0%)

Dimmed sight, sweating, tremor, unconsciousness, and possible death


What Level of CO2 is Dangerous?


CO2 becomes dangerous when its air concentration exceeds about 3 per cent. The symptoms are shortness of breath and increased heart rate and blood pressure. They may vary between each person and depends on how long they breathe in this air.


How Can You Reduce CO2 Concentration Indoors?


  • Install and maintain a ventilation system that will bring in fresh outdoor air. The CO2 particles will dilute in this air keeping a low CO2 concentration.
  • If you don't want to invest in expensive indoor air quality systems, you can ventilate your home manually by opening a window. Do it for 10 - 15 minutes, and the CO2 levels will be drastically lower. This is especially important when you cook, light candles or a fireplace (open flame consumes O2 and produces CO2). It is also a good idea to open a window or at least a bedroom door while sleeping. Scientists have shown the fresh air will help you sleep better.
  • Smoke outside or open a window to prevent smoke from seeping back indoors.
  • Studies have shown the highest CO2 readings were found in crowded areas during commuting (e.g., train) or indoors. Try to avoid such situations or let some fresh air inside by opening windows or doors.

Picture: a photograph of some people working at a table on laptops

Article written by Ella Tansley | Published 20 July 2021


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