Air pollution can be made up of many components such as ozone, volatile organic compounds (VOCs), larger particulate matter like dust and sand found in PM10, and the smallest particulate matter, PM2.5 (particulate matter that are 2.5 microns in diameter or smaller) and ultrafine particles. While particulate matter is the most common air pollutant and has the most direct impact on human health, carbon dioxide shouldn’t be overlooked.

Carbon dioxide can significantly impact human health by increasing blood pressure, raising heart rates, and can contribute to a range of other health symptoms. These pollutants can be invisible for most - until they are made known with the help of an air quality monitor.

What is carbon dioxide?

Carbon dioxide, or CO2, is a nontoxic, noncombustible air pollutant and a colorless greenhouse gas. It’s a natural product of human and animal respiration and can be created naturally through processes like volcanic eruptions. However, most carbon dioxide emissions are human produced through human activity.

Primary sources of carbon dioxide can include (1):

• fossil fuel combustion from transportation
• electricity production
• industrial sources
• heating for homes
• deforestation and wildfires
• agricultural burning

A warming planet with hotter, drier seasons is leading to increases in global carbon dioxide emissions. In just one summer in 2021, wildfires burning in California generated more carbon dioxide than had previously been created in any one summer during the past twenty years (2).

Indoor sources of carbon dioxide can include stovetop flames and ovens, fireplaces, and outdoor sources like factories and vehicle traffic.

Carbon dioxide should not be confused with carbon monoxide (CO), another pollutant and a more deadly gas caused by incomplete combustion.

Carbon dioxide health effects

While carbon dioxide is good for plants as it helps photosynthesis, too much carbon dioxide isn’t good for human beings and animals.

Exposure to small amounts of carbon dioxide is mostly safe. But carbon dioxide can impact indoor air quality and threaten human health when it builds up to dangerous concentrations.

As an asphyxiant, carbon dioxide replaces normal, breathable oxygen. Most of the health affects associated with carbon dioxide exposure come from oxygen depletion.

While outdoor carbon dioxide measurements of 380 parts per million (ppm) are common, they can reach up to 500 ppm in outdoor urban areas (3). Biological functions can be changed at measurements between 500 ppm and 5,000 ppm (4). A large build-up of CO2 concentrations can be life-threatening; measurements greater than 20,000 ppm can impact breathing, while 250,000 ppm can result in death.

Higher concentrations of carbon dioxide can affect health in several ways, including (5,6):

• impaired decision-making
• lethargy
• headache
• restlessness and inattention
• drowsiness
• rapid heart rate
• increased blood pressure
• dizziness, vomiting, and nausea

How to monitor carbon dioxide

One of the most important tools for protecting breathing spaces from airborne pollutants is an air quality monitor equipped to detect carbon dioxide.

AirVisual Series air quality monitors share data and the relative health threat of PM2.5 and carbon dioxide while providing temperature, humidity, and air pressure information.

An AirVisual Outdoor air quality monitor equipped with an optional carbon dioxide sensor provides air pollutant data to the AirVisual mobile app, downloadable on Google play or the Apple Store. Data can also be provided to a dashboard, to a website through a widget, connected to home technology, or shared creatively through APIs.

More practically, air quality monitor data can be connected to a building management system using APIs or IFTTT triggers. When PM2.5 or CO2 thresholds are met, HVAC fans can provide both ventilation and filtration.

Setting a CO2 alert at around 900 to 1,000 ppm may be a good choice to prevent CO2 buildup from reaching dangerous levels. Alerts can be set to the AirVisual app, website, or email to trigger building management system and can be seen on the device display.

When both the indoor and outdoor air quality monitors are paired onsite, it’s then possible to have a more complete picture of air quality in and out of a building.

Air quality data contributors can also share their outdoor air quality data. By registering an air quality monitoring device, local data can be shared for people around the globe. Global air quality awareness increases environmental literacy and informs anyone in the area about possible exposure to pollutants.

The takeaway

Monitoring air pollution empowers action. Monitoring air quality data gives people the ability to take prompt action to counter air pollution threats, including a build-up of carbon dioxide.

If you know there’s too much carbon dioxide in your indoor space, you can control how you respond by immediately improving the ventilation. Allow in fresh air and make sure your HVAC (heating, ventilation, and air conditioning) system is in good working order. If letting in outdoor air increases air pollution exposure, mechanical ventilation with filtration can reduce exposure to pollution while lowering carbon dioxide.