Carbon Dioxide (CO₂) Gas: What You Should Know

Human activity has added to these natural processes, with energy production, transportation, and industrial manufacturing contributing significantly to atmospheric CO₂ levels.

Although it is colourless and odourless, carbon dioxide has a strong influence on global systems. It is vital for sustaining life, yet it also presents environmental challenges, particularly in connection with climate change. Understanding CO₂—its properties, sources, uses, and impacts—remains critical across industries, environmental management, and workplace safety.

Physical and Chemical Properties

Physical Properties

Carbon dioxide is a colourless, odourless gas at room temperature and atmospheric pressure. It is heavier than air, with a density around 1.5 times that of air, which means it can accumulate in low-lying or enclosed spaces if not properly ventilated.

CO₂ can exist in three physical states depending on temperature and pressure:

• As a gas under standard atmospheric conditions.
• As a liquid when compressed at high pressure and cooled below 31°C (its critical temperature).
• As a solid, known as dry ice, when frozen at temperatures below −78.5°C without passing through a liquid phase under normal atmospheric pressure.

The ability of CO₂ to form dry ice, which sublimates directly from solid to gas without becoming liquid, makes it particularly useful for refrigeration and specialised cooling applications.

Chemical Properties

Chemically, carbon dioxide behaves as an acidic oxide. When it dissolves in water, it forms carbonic acid (H₂CO₃), a weak acid that plays an important role in regulating blood pH in humans and influencing the acidity of oceans.

CO₂ is generally stable and non-flammable. However, it interacts with other substances in important ways:

• It is a natural byproduct of combustion reactions involving carbon-based fuels.
• It is continuously cycled through biological processes such as respiration and photosynthesis.

These properties allow carbon dioxide to participate in both environmental systems and industrial processes without posing a risk of combustion itself.

Sources of Carbon Dioxide

Natural Sources

Carbon dioxide is produced naturally through a variety of processes that are vital to the Earth’s systems. Some of the primary natural sources include:

• Respiration: Animals, plants, and microorganisms release CO₂ as a byproduct of metabolising food for energy.
• Decomposition: As organic matter breaks down, microorganisms consume it and emit carbon dioxide.
• Volcanic Activity: Volcanic eruptions release gases from beneath the Earth’s surface, including substantial amounts of CO₂.
• Ocean-Atmosphere Exchange: The world’s oceans absorb carbon dioxide from the atmosphere and release it back, maintaining a dynamic balance as part of the natural carbon cycle.
  

These sources contribute to a relatively steady background level of CO₂ in the atmosphere under natural conditions.

Human-Made Sources

Since the Industrial Revolution, human activities have significantly increased the amount of carbon dioxide in the atmosphere. Major anthropogenic sources include:

• Fossil Fuel Combustion: The burning of coal, oil, and natural gas for energy and transportation releases large quantities of CO₂.
• Industrial Processes: Manufacturing activities such as cement production, steelmaking, and chemical processing emit carbon dioxide as a byproduct.
• Deforestation and Land-Use Changes: Clearing forests reduces the number of trees available to absorb CO₂ through photosynthesis, while decaying plant material adds further emissions.
• Agriculture: Agricultural practices, including soil management and livestock farming, release both direct and indirect carbon dioxide emissions.
  Waste Management: Decomposition of organic waste in landfills produces carbon dioxide alongside other greenhouse gases.

The growing impact of these human-made sources has contributed to the rising concentration of CO₂ in the atmosphere, influencing climate systems and environmental health worldwide.

Role of Carbon Dioxide in the Environment

The Carbon Cycle

Carbon dioxide is a central component of the Earth’s carbon cycle, the continuous movement of carbon among the atmosphere, oceans, soil, and living organisms.

• Photosynthesis: Plants, algae, and certain bacteria absorb CO₂ from the atmosphere and use it to produce energy through photosynthesis, releasing oxygen as a byproduct.
• Respiration and Decomposition: Animals and plants return carbon dioxide to the atmosphere through respiration. When organisms die, decomposers break them down, releasing stored carbon back into the environment.
• Ocean-Atmosphere Exchange: Oceans act as both a sink and a source for carbon dioxide, absorbing it from the atmosphere and releasing it depending on temperature, salinity, and biological activity.

This natural cycling of carbon helps regulate atmospheric CO₂ levels, maintaining conditions suitable for life.

Impact on Climate and Environment

Carbon dioxide is one of the primary greenhouse gases responsible for trapping heat in the Earth’s atmosphere. While this natural greenhouse effect is necessary to sustain life by keeping the planet warm, excessive CO₂ levels intensify the effect, contributing to global warming and climate change.

Elevated atmospheric CO₂ concentrations have been linked to:

• Rising global temperatures.
• Increased frequency of extreme weather events.
• Shifts in climate patterns and precipitation.
• Rising sea levels due to the melting of ice caps and thermal expansion of seawater.

In addition, the absorption of excess atmospheric CO₂ by the oceans leads to ocean acidification, which affects marine ecosystems, particularly coral reefs, shellfish, and other organisms that rely on calcium carbonate for their shells and skeletons.

Contribution to Plant Growth

Carbon dioxide is essential for plant growth, and higher concentrations can, under controlled conditions, promote more vigorous photosynthesis and potentially higher crop yields. This phenomenon, sometimes referred to as the “CO₂ fertilisation effect,” has been observed in greenhouse environments where CO₂ levels are carefully regulated.

However, outside of controlled systems, the benefits of increased atmospheric CO₂ for agriculture are often offset by changes in temperature, water availability, and other climatic factors, making the overall impact complex and variable across regions.

Applications of Carbon Dioxide

Industrial Applications

Carbon dioxide is widely used across industries for its chemical and physical properties.

• Beverage Industry: CO₂ is used to carbonate soft drinks, beer, and sparkling water, giving them their distinctive effervescence.
• Refrigeration and Cooling: Solid carbon dioxide, known as dry ice, is commonly used for transporting perishable goods. Dry ice provides cooling without leaving liquid residue, making it ideal for temperature-sensitive items.
• Fire Suppression: CO₂ is used in fire extinguishers for electrical fires and flammable liquid fires. It works by displacing oxygen, thereby suffocating the fire without damaging sensitive equipment.
• Welding and Metal Fabrication: In industries such as automotive manufacturing, CO₂ serves as a shielding gas in metal inert gas (MIG) welding processes, protecting the weld area from atmospheric contamination.

Environmental and Energy Applications

The role of carbon dioxide in environmental management and energy production is expanding.

• Carbon Capture and Storage (CCS): Industrial facilities use CCS technology to capture CO₂ emissions before they enter the atmosphere. The gas is then compressed and stored underground in geological formations, helping to reduce greenhouse gas emissions.
• Enhanced Oil Recovery (EOR): In the energy sector, CO₂ is injected into depleted oil fields to increase pressure and stimulate the extraction of additional oil. This process both boosts resource recovery and stores carbon dioxide underground.

Medical and Healthcare Applications

Carbon dioxide also plays important roles in medical science and healthcare:

• Surgical Procedures: During minimally invasive surgeries such as laparoscopies, CO₂ is used to inflate the body cavity, providing better visibility and access for surgeons.
• Respiratory Therapy and Diagnostics: Medical-grade CO₂ is used in respiratory therapies and as part of diagnostic procedures to assess lung function and blood pH levels.
• Cryotherapy: Solid and liquid carbon dioxide can be used in cryotherapy treatments for removal of skin lesions and in certain dermatological therapies.

Commercial Applications

Beyond industrial and medical uses, CO₂ finds applications in everyday commercial activities:

• Food Preservation: Carbon dioxide is used in modified atmosphere packaging to extend the shelf life of fresh produce, meats, and bakery products by slowing microbial growth.
• Industrial Cleaning: Dry ice blasting, which uses solid CO₂ pellets, is an environmentally friendly cleaning method used to remove contaminants from equipment, machinery, and surfaces without the use of chemical solvents.

These diverse applications underline carbon dioxide’s role as a versatile industrial and commercial resource, even as efforts continue to better manage its environmental impact.

Health Hazards of Carbon Dioxide

Although carbon dioxide is a natural part of the air we breathe, elevated concentrations can present serious health risks, particularly in confined or poorly ventilated spaces.

Toxicity and Exposure Risks

At typical atmospheric levels, carbon dioxide is harmless. However, when concentrations rise above normal levels, it can displace oxygen in the air, creating an environment where breathing becomes difficult. High levels of CO₂ can lead to asphyxiation without any noticeable warning signs, as the gas is both colourless and odourless.

Confined spaces such as basements, storage rooms, fermentation tanks, and underground facilities are particularly vulnerable to dangerous CO₂ accumulation if proper ventilation and monitoring are not in place.

Short-Term Exposure Effects

Exposure to elevated levels of carbon dioxide can cause a range of symptoms depending on the concentration and duration. Common short-term effects include:

• Headaches
• Dizziness
• Shortness of breath
  Increased heart rate
• Fatigue and confusion

At concentrations above 5,000 parts per million (ppm), symptoms can become more pronounced, and exposure to levels above 40,000 ppm can quickly lead to unconsciousness or death without intervention.

Long-Term Exposure Risks

Chronic exposure to moderately elevated CO₂ levels, such as in some poorly ventilated work environments, may lead to more persistent health issues. These can include:

• Respiratory problems
• Impaired cognitive function
• Sleep disturbances

For workplaces where elevated carbon dioxide levels may be present, it is essential to monitor air quality and implement appropriate ventilation and safety measures to protect workers’ health over the long term.

Environmental Impacts of Carbon Dioxide

Contribution to Climate Change

Carbon dioxide is a major greenhouse gas, playing a significant role in warming the Earth’s atmosphere. As more CO₂ is emitted, more heat is trapped near the planet’s surface, disrupting natural climate systems. This enhanced greenhouse effect has been linked to:

• Rising average global temperatures.
• Increased frequency and severity of droughts, floods, and storms.
• Changes in regional climate patterns, affecting agriculture and water supplies.
• Accelerated melting of polar ice and glaciers, contributing to rising sea levels.

The steady accumulation of atmospheric CO₂, primarily from the burning of fossil fuels, remains a central driver of current climate change challenges worldwide.

Ocean Acidification

Another serious consequence of excess atmospheric carbon dioxide is ocean acidification. As oceans absorb CO₂, it reacts with seawater to form carbonic acid, lowering the pH of marine environments.

This change in ocean chemistry impacts many marine species, particularly those that rely on calcium carbonate to form shells and skeletons, such as:

• Corals
• Molluscs
• Crustaceans

Weakened shells and coral bleaching events can have widespread effects on marine biodiversity, fisheries, and coastal economies dependent on healthy ocean ecosystems.

Role in Deforestation

Deforestation not only releases stored carbon dioxide when trees are cut down and burned or left to decompose, but also removes vital carbon sinks that would otherwise absorb CO₂ from the atmosphere.

The loss of forests contributes to:

• Higher atmospheric CO₂ concentrations.
• Disruption of local and global climate regulation.
• Decreased biodiversity and ecosystem resilience.

Protecting and restoring forests is widely recognised as a key strategy for managing atmospheric carbon dioxide levels and mitigating broader environmental impacts.

Monitoring and Detection of CO₂

Accurate monitoring of carbon dioxide levels is essential in many environments, particularly where CO₂ emissions or accumulation could pose risks to human health, operational processes, or environmental compliance.

Detection Technologies

Several technologies are used to measure and monitor carbon dioxide concentrations reliably:

• Infrared Sensors: These sensors detect CO₂ by measuring the absorption of infrared light at specific wavelengths. They offer precise, stable readings and are widely used in fixed and portable gas detection systems.
• Non-Dispersive Infrared (NDIR) Sensors: NDIR sensors are a common choice for industrial applications. They use an optical filter to detect specific gas concentrations without interference from other gases, making them highly reliable.
• Portable CO₂ Monitors: Handheld devices allow workers to measure carbon dioxide levels in confined spaces or during inspections. These monitors are particularly important in industries such as brewing, manufacturing, and food processing.

Each of these technologies provides critical early warning capabilities, helping to prevent dangerous accumulations of carbon dioxide in workspaces.

Monitoring in Industrial and Environmental Settings

Continuous monitoring is a standard practice in industries where carbon dioxide is produced, stored, or used. Key applications include:

• Workplace Safety: Fixed CO₂ detection systems are installed in production facilities, laboratories, breweries, and storage areas. These systems provide real-time readings and trigger alarms if concentrations approach unsafe levels.
• Environmental Monitoring: Beyond workplace environments, CO₂ levels are tracked for emissions reporting and compliance with environmental regulations. Monitoring stations around the world collect data to assess long-term trends in atmospheric carbon dioxide concentrations.

Implementing accurate detection systems supports safer work environments, regulatory compliance, and environmental stewardship.

Safety Measures and Protocols

Given the potential health risks of elevated carbon dioxide levels, especially in confined or industrial environments, implementing effective safety measures is essential to protect personnel and maintain safe operations.

Industrial Safety Practices

• Ventilation Systems: Ensuring adequate ventilation is one of the most effective ways to prevent carbon dioxide buildup. Systems should be designed to maintain safe ambient air concentrations, especially in enclosed or underground areas.
  
• Gas Detection and Alarm Systems: Installing continuous monitoring equipment with audible and visual alarms helps alert workers to elevated CO₂ levels before they reach dangerous thresholds.
• Regular Maintenance and Inspection: Safety equipment, including sensors and ventilation systems, must be inspected, calibrated, and maintained regularly to ensure reliable performance. (Find out more: The Importance of Gas Detection Audits)

Personal and Emergency Safety

• Worker Training: Employees who work in environments where carbon dioxide is present should receive training on recognising the signs of CO₂ exposure, using monitoring equipment, and following emergency response procedures.
• Personal Protective Equipment (PPE): In high-risk areas, workers may require PPE such as respirators, particularly during maintenance activities or in the event of a leak.
• Emergency Protocols: Clear plans should be in place for evacuations and emergency response. Facilities should conduct regular drills to ensure all personnel know how to respond to a CO₂ incident.

Engineering Controls

Beyond ventilation and monitoring, additional engineering solutions can help manage carbon dioxide risks:

• Emission Control Systems: Technologies can be implemented to capture or neutralise CO₂ emissions at the source, reducing workplace concentrations.
• Process Modifications: Adjusting industrial processes to minimise CO₂ release can also contribute to a safer environment.

Establishing a comprehensive safety programme that combines detection, engineering controls, worker education, and emergency preparedness forms the foundation for effective carbon dioxide management.

Global Efforts and Regulations

As carbon dioxide emissions continue to drive environmental change, global and national initiatives have been introduced to manage and reduce CO₂ levels. These efforts focus on both mitigation and adaptation strategies to limit long-term impacts on the planet.

International Agreements

• Paris Climate Agreement: Adopted in 2015, the Paris Agreement aims to limit global warming to well below 2°C above pre-industrial levels, with efforts to restrict the increase to 1.5°C. Participating countries have committed to reducing greenhouse gas emissions, including carbon dioxide, through nationally determined contributions (NDCs) and periodic progress reviews.
• Global Carbon Neutrality Initiatives: Many international organisations, industries, and alliances have set goals to achieve net-zero carbon emissions by mid-century. These initiatives encourage the adoption of renewable energy, reforestation, carbon capture technologies, and sustainable development practices.

Collaborative international efforts are critical for addressing the global nature of CO₂ emissions and their environmental consequences.

National Policies

Countries around the world have implemented a variety of measures to regulate carbon dioxide emissions at the national level:

• Emission Standards: Governments establish permissible limits for CO₂ emissions from industries, vehicles, and energy producers to promote cleaner operations.
• Carbon Pricing Mechanisms: Tools such as carbon taxes and cap-and-trade systems place a financial cost on emitting carbon dioxide, incentivising businesses to reduce their carbon footprint.
• Investment in Renewable Energy: Many countries provide support for solar, wind, hydroelectric, and hydrogen energy projects to shift away from fossil fuels.
• Afforestation and Reforestation Programmes: Encouraging the planting of trees and restoring forests helps create additional carbon sinks to absorb atmospheric CO₂.

The combination of global cooperation and national action represents a growing commitment to managing carbon dioxide emissions and protecting environmental health for future generations.

Innovations and Future Outlook

Ongoing innovation and investment are shaping how industries and governments manage carbon dioxide emissions. New technologies and evolving strategies offer promising approaches to reducing atmospheric CO₂ and adapting to environmental challenges.

Carbon Capture and Utilisation (CCU)

Beyond simply capturing carbon dioxide, carbon capture and utilisation technologies seek to transform CO₂ into valuable products. Some of the leading developments include:

• Synthetic Fuels: Captured CO₂ can be combined with hydrogen to create synthetic fuels that serve as alternatives to conventional fossil fuels.
• Building Materials: Carbon dioxide is being used to cure concrete and produce carbon-negative building blocks, helping to store CO₂ permanently while reducing emissions from construction.
• Industrial Chemicals: Researchers are developing processes to convert CO₂ into chemicals used in plastics, fertilisers, and other industrial applications.

These technologies aim to create circular carbon economies, where carbon dioxide is not simply treated as waste but used as a resource.

Renewable Energy Development

The global transition to renewable energy sources remains one of the most effective strategies for reducing carbon dioxide emissions:

• Solar and Wind Power: Advances in efficiency and storage technology are making renewable energy sources more viable for large-scale electricity generation.
• Hydrogen Energy: Hydrogen produced from renewable sources (“green hydrogen”) offers a clean alternative for industries that are difficult to decarbonise, such as steelmaking and aviation.

Investing in renewable infrastructure reduces reliance on fossil fuels, helping to slow the rise of atmospheric CO₂ concentrations.

Goals for Carbon Neutrality

Many countries, industries, and organisations have set targets to achieve carbon neutrality within the coming decades. Strategies to reach these goals include:

• Increasing energy efficiency across all sectors.
• Expanding afforestation efforts to enhance carbon sinks.
• Developing more resilient agricultural systems that reduce emissions while maintaining food security.

Continued progress will rely on combining technology, policy measures, and community engagement to build a more sustainable relationship with the Earth’s carbon cycle.

* * *

Carbon dioxide is a natural and necessary part of the Earth’s atmosphere, playing a critical role in supporting plant life and regulating the planet’s climate. However, rising CO₂ levels linked to human activities have brought new challenges, including global warming, ocean acidification, and disruptions to natural ecosystems.

Understanding the properties, sources, impacts, and applications of carbon dioxide provides valuable insight into how industries, governments, and communities can better manage its presence. Through monitoring, safety protocols, technological innovation, and global cooperation, there are clear pathways to balancing carbon dioxide’s benefits with its risks.

Managing carbon dioxide effectively is not just a technical challenge—it is a collective responsibility across sectors and societies.

For expert advice on carbon dioxide monitoring, detection solutions, or workplace safety assessments, contact OBW Technologies today. Our team is ready to support your operations with reliable expertise and advanced technologies.