Negative effects of carbon dioxide on the environment

Also known as: Carbonic acid gas; Dry Ice; CO2; Diesel Exhaust Component
Chemical reference number (CAS): 124-38-9

Table of Contents Show

Transportation and Climate Change
EPA Programs to Reduce Carbon Pollution from Transportation
Setting GHG Emissions Standards for Cars and Trucks
Increasing the Use of Renewable Fuels
Taking First Steps to Set a Greenhouse Gas Standards for Aircraft
Greening the Federal Fleet
Reducing Greenhouse Gas Emissions Associated with Moving Goods
Informing Consumers Information on Fuel Economy and Advanced Technology Cars
State and Local Transportation Resources Center
The Road Ahead
How does carbon dioxide negatively affect the environment?
How is carbon affecting the environment?

CO2 is the fourth most abundant gas in the earth's atmosphere. At room temperature, carbon dioxide (CO2) is a colorless, odorless, non-flammable gas, at other temperatures and pressures, carbon dioxide can be a liquid or a solid. Solid carbon dioxide is called dry ice because it slowly changes from a cold solid directly into a gas.

Carbon dioxide is a byproduct of normal cell function when it is breathed out of the body. CO2 is also produced when fossil fuels are burned or decaying vegetation. Surface soils can sometimes contain high concentrations of this gas, from decaying vegetation or chemical changes in the bedrock.

In its solid form, carbon dioxide is used in fire extinguishers, in laboratories, and in theater and stage productions as dry ice to make fog. The use of dry ice can elevate indoor CO2 if the air is not ventilated.

Where CO2 levels in soils are high, the gas can seep into basements through stone walls or cracks in floors and foundations. CO2 can also build up in buildings that house a lot of people or animals, and is a symptom of problems with fresh air circulation in the building or home. High levels of CO2 can displace oxygen (O2) and nitrogen (N2), potentially causing health problems.

How to avoid exposure:

Have an HVAC or weatherization contractor measure CO2 levels within your home. If the levels exceed 1,000 ppm, the furnace should be tuned to increase levels of fresh air coming into the building. If levels are above 2,000 ppm, this can be a serious condition that could warrant HVAC modification.
Never use a fire extinguisher or dry ice in a manner by which it was not intended.
Never enter a liquid manure pit without protective equipment since CO2, along with ammonia, methane, and hydrogen sulfide generated from decomposing manure can quickly cause loss of consciousness and death.
Use care when entering silos since CO2 can build up from the decomposing grain.

There are no indoor air standards for CO2; however, high indoor air levels of carbon dioxide could be an indicator the HVAC (heating, ventilation, and air conditioning) system is not working properly.

The amount of carbon dioxide in a building is usually related to how much fresh air is being brought into that building. In general, the higher the CO2 level in the building, the lower the amount of fresh air exchange. Therefore, examining levels of CO2 in indoor air can reveal if the HVAC systems are operating within guidelines. CO2 levels are usually measured in percent (%) of air or parts per million (ppm). High CO2 levels, generally over 1000 ppm, indicate a potential problem with air circulation and fresh air in a room or building. In general, high CO2 levels indicate the need to examine the HVAC system. High carbon dioxide levels can cause poor air quality and can even extinguish pilot lights on gas-powered appliances.

Everyone's Reaction is Different

A person's reaction to chemicals depends on several things, including individual health, heredity, previous exposure to chemicals including medicines, and personal habits such as smoking or drinking. It’s also important to consider the length of exposure to the chemical, the amount of chemical exposure, and whether the chemical was inhaled, touched, or eaten.

Exposure to CO2 can produce a variety of health effects. These may include headaches, dizziness, restlessness, a tingling or pins or needles feeling, difficulty breathing, sweating, tiredness, increased heart rate, elevated blood pressure, coma, asphyxia, and convulsions.

The levels of CO2 in the air and potential health problems are:

400 ppm: average outdoor air level.
400–1,000 ppm: typical level found in occupied spaces with good air exchange.
1,000–2,000 ppm: level associated with complaints of drowsiness and poor air.
2,000–5,000 ppm: level associated with headaches, sleepiness, and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present.
5,000 ppm: this indicates unusual air conditions where high levels of other gases could also be present. Toxicity or oxygen deprivation could occur. This is the permissible exposure limit for daily workplace exposures.
40,000 ppm: this level is immediately harmful due to oxygen deprivation.

Last Revised: June 15, 2022

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Transportation and climate change
EPA programs to reduce carbon pollution

Transportation and Climate Change

Burning fossil fuels like gasoline and diesel releases carbon dioxide, a greenhouse gas, into the atmosphere. The buildup of carbon dioxide (CO2) and other greenhouse gases like methane (CH4), nitrous oxide (N2O), and hydrofluorocarbons (HFCs) is causing the Earth’s atmosphere to warm, resulting in changes to the climate we are already starting to see today.

Greenhouse gas (GHG) emissions from transportation account for about 27 percent of total U.S. greenhouse gas emissions, making it the largest contributor of U.S. GHG emissions. Between 1990 and 2020, GHG emissions in the transportation sector increased more in absolute terms than any other sector.

Learn more:

Global emissions by economic sector
Fast facts on transportation greenhouse gas emissions

EPA Programs to Reduce Carbon Pollution from Transportation

EPA is addressing climate change by taking the following actions to reduce GHG emissions from the transportation sector. Many of these programs have benefits beyond cutting carbon. For example, decreasing fuel consumption can reduce our dependence on foreign oil and save consumers money at the pump.

Setting GHG Emissions Standards for Cars and Trucks

EPA and DOT issued a joint rule-making that set GHG emissions and fuel economy standards for the largest sources of greenhouse gases from transportation, including cars, light trucks, and heavy-duty trucks.

Light-duty GHG regulations for passenger vehicles and trucks are projected to:

Cut 6 billion metric tons of GHG emissions over the lifetimes of the vehicles sold in model years 2012-2025 and allowing manufacturers flexibility in meeting the standards;
Nearly double the fuel efficiency while protecting consumer choice; and
Reduce America’s dependence on oil and provide significant savings for consumers at the pump.

Heavy-duty GHG regulations are projected to:

Reduce CO2 emissions by about 270 million metric tons over the life of vehicles built under the program, saving about 530 million barrels of oil; and
The proposed “Phase 2” program includes standards that would further reduce GHG emissions and improve the fuel efficiency of medium and heavy-duty trucks.

Learn more:

Regulations for GHG emissions from passenger cars & trucks (light-duty)
Regulations for GHG emissions from commercial trucks & buses (heavy-duty)
The Automotive Trends Report (formerly the Manufacturer Performance Report)
Analyses and reports for setting GHG emissions standards for cars and trucks

Increasing the Use of Renewable Fuels

Congress created the Renewable Fuel Standard program in an effort to reduce greenhouse gas emissions and expand the nation’s renewable fuels sector while reducing reliance on imported oil. Renewable fuels are produced from plants, crops and other biomass, and can reduce greenhouse gas emissions when compared to burning the fossil fuels they replace.

Renewable Fuel Standard Program

Taking First Steps to Set a Greenhouse Gas Standards for Aircraft

EPA along with the Federal Aviation Agency at the United Nations' International Civil Aviation Organization have developed international carbon dioxide emissions standards for aircraft. EPA is also now working through the process of potentially setting domestic regulations under the Clean Air Act that address GHG emissions from certain classes of engines used in aircraft.

Learn more:

Regulations for GHG emissions from aircraft

Greening the Federal Fleet

The 2007 Energy Independence and Security Act requires federal agencies to only acquire cars, light trucks, or medium-duty passenger vehicles that are low greenhouse gas emitting. Each year, EPA evaluates the greenhouse gas emissions performance of the fleet to determine which vehicles in each class emit less harmful greenhouse gases. The law requires federal agencies to purchase these high performing vehicles. Over time this will result in a greener federal fleet.

Learn more:

Federal fleets

Reducing Greenhouse Gas Emissions Associated with Moving Goods

SmartWay helps the freight transportation sector improve supply chain efficiency, reducing greenhouse gases and saving fuel costs for companies who participate. Through SmartWay, EPA and its partners are making significant gains in the efficiency of how our nation moves goods, helping address air quality challenges, improving public health and reducing freight’s contribution to climate change.

Learn more:

SmartWay

Informing Consumers Information on Fuel Economy and Advanced Technology Cars

Since the mid-1970s EPA has required automakers to display a label on new cars and light trucks with information on vehicles' fuel economy and fuel costs. Labels on today's cars also include ratings on greenhouse gas and smog-forming pollutants. EPA provides online resources, such as the Green Vehicle Guide and the joint EPA-DOE website fueleconomy.gov, to help consumers identify vehicles that can save them money at the pump and reduce their transportation-related emissions.

EPA’s SmartWay light duty program goes further and identifies the top performing vehicles in terms of fuel economy and emissions to assist consumers in making an environmentally friendly purchase.

Learn more:

Green Vehicle Guide
Fueleconomy.gov
Consider a SmartWay vehicle

State and Local Transportation Resources Center

For information on emission reduction strategies, national policies and regulations, incentive-based and voluntary programs, funding sources, calculators, transportation conformity, and other types of assistance to help states and local areas achieve their air quality and transportation objectives.

Learn more:

State and Local Transportation Resources

The Road Ahead

While transportation continues to contribute a large percentage of U.S. emissions, there are many opportunities for the sector to deliver greenhouse gas reductions. Low-carbon fuels, new and improved vehicle technologies, strategies to reduce the number of vehicle miles traveled, and operating vehicles more efficiently are all approaches to reducing greenhouse gases from transportation.

How does carbon dioxide negatively affect the environment?

CO2 has proven to be a significant contributor to air pollution, taking a substantial role in the greenhouse effect. That's because carbon dioxide traps radiation at the ground level, resulting in ground-level ozone. That prevents the earth from cooling during the night and warms ocean waters.

How is carbon affecting the environment?

Our carbon footprint has a negative impact on the environment in multiple ways: It is the main cause of human-induced climate change, it contributes to urban air pollution, it leads to toxic acid rain, it adds to coastal and ocean acidification, and it worsens the melting of glaciers and polar ice.