Do Air Purifiers Get Rid of CO2 The Truth Revealed

Air purifiers do not remove CO2—most use filters like HEPA or activated carbon that target pollutants, allergens, and odors, but not carbon dioxide. To reduce CO2 levels, proper ventilation or specialized systems like ERVs are essential, as traditional air purifiers simply recirculate existing air without lowering CO2 concentration.

Key Takeaways

• Air purifiers do not remove CO2: they target particles and gases, not carbon dioxide.
• Ventilation is key for CO2 reduction: open windows or use HVAC systems to lower CO2 levels.
• CO2 accumulates in sealed spaces: monitor indoor levels, especially in offices or classrooms.
• Use CO2 monitors: track levels to know when to improve airflow.
• Plants have minimal impact: they absorb little CO2 and won’t solve high concentrations.
• Choose purifiers for pollutants, not CO2: focus on HEPA and activated carbon filters for other contaminants.

Do Air Purifiers Get Rid of CO2? The Truth Revealed

You’ve probably seen the sleek air purifiers sitting quietly in living rooms, bedrooms, and even offices—whirring away like tiny guardians of clean air. Maybe you’ve even bought one, hoping it would clear the stuffy feeling in your home, reduce allergies, or help you breathe easier. But here’s a question that often gets buried under marketing claims and technical jargon: Do air purifiers actually get rid of CO2?

I’ll be honest—I used to assume they did. After all, they’re called “air purifiers,” right? If they clean the air, surely they remove carbon dioxide too. But the more I dug into how these devices actually work, the more I realized I had it wrong. CO2—carbon dioxide—is a colorless, odorless gas that we all exhale with every breath. It builds up indoors, especially in tightly sealed homes or crowded rooms, and high levels can make you feel drowsy, unfocused, or even give you a headache. So it’s natural to wonder: can an air purifier fix that?

The short answer? No, standard air purifiers do not remove CO2 from the air. But that doesn’t mean they’re useless—or that you’re out of options. In this post, I’ll walk you through what air purifiers actually do, why they can’t handle CO2, and what you can do to reduce indoor CO2 levels. Think of this as your friendly, no-nonsense guide to understanding indoor air quality—without the sales pitch.

What Is CO2 and Why Does It Matter Indoors?

Before we dive into air purifiers, let’s talk about CO2 itself. Carbon dioxide is a natural part of Earth’s atmosphere. We produce it when we breathe, and plants absorb it during photosynthesis. In outdoor environments, CO2 levels hover around 400–420 parts per million (ppm). That’s perfectly normal. But indoors, especially in energy-efficient homes with little airflow, CO2 can climb much higher.

How CO2 Builds Up Inside Your Home

Every time you breathe, you exhale CO2. If you’re in a room with poor ventilation—say, a bedroom with the windows closed all night—CO2 levels can rise quickly. The same goes for offices, classrooms, or even your home gym. Add in a few people, and the problem gets worse. Studies show that CO2 levels in classrooms can exceed 1,000 ppm during the day, and in some cases, even reach 3,000 ppm.

Here’s why that matters: while CO2 isn’t toxic at these levels, it does affect how you feel and think. At around 1,000 ppm, people often report feeling tired or having trouble concentrating. At 2,000 ppm or higher, symptoms like headaches, dizziness, and increased heart rate can kick in. It’s not dangerous in the short term, but it’s definitely not comfortable—and it can hurt productivity and sleep quality.

Common Sources of Indoor CO2

• Human respiration: The biggest source in most homes. More people = more CO2.
• Gas stoves and heaters: These burn fuel and release CO2 as a byproduct.
• Fireplaces and candles: Even small flames produce CO2.
• Poor ventilation: Without fresh air coming in, CO2 accumulates.

So while CO2 isn’t a pollutant in the same way as smoke or mold, it’s still something you want to manage—especially if you spend a lot of time indoors. The challenge? Most air purifiers aren’t designed to tackle it.

How Do Air Purifiers Actually Work?

Now that we understand CO2, let’s look at what air purifiers are built to do. The truth is, they’re not one-size-fits-all devices. Different models use different technologies, and each has its strengths and limitations.

HEPA Filters: The Gold Standard for Particles

The most common type of air purifier uses a HEPA (High-Efficiency Particulate Air) filter. These filters are incredibly effective at trapping tiny particles like dust, pollen, pet dander, and even some bacteria and viruses. A true HEPA filter can capture 99.97% of particles as small as 0.3 microns.

But here’s the catch: CO2 molecules are way smaller—about 0.0004 microns. That’s over 700 times smaller than what HEPA filters are designed to catch. So while a HEPA filter can make your air feel cleaner by removing allergens and irritants, it does absolutely nothing for CO2.

Activated Carbon Filters: Great for Odors, Not Gases Like CO2

Some air purifiers include activated carbon filters, which are great at absorbing odors, smoke, and volatile organic compounds (VOCs) like those from cleaning products or paint. The carbon has a porous structure that traps certain chemicals as air passes through.

But again, CO2 is a small, non-reactive gas. It doesn’t bind well to carbon the way larger, more complex molecules do. So while activated carbon can help with smells and some chemicals, it’s not effective for reducing CO2 levels.

Other Technologies: UV, Ionizers, and Ozone

Some purifiers use UV light to kill bacteria or ionizers to charge particles so they stick to surfaces. Others produce ozone, which can react with pollutants—but is itself a lung irritant and not recommended for home use.

None of these technologies remove CO2. UV light doesn’t break down CO2 molecules. Ionizers don’t capture gases. And ozone generators? They’re more likely to make your air quality worse than better.

So while air purifiers can make a real difference for people with allergies or asthma, they’re not the solution for CO2 buildup. That’s an important distinction—and one that’s often overlooked in product descriptions.

Why Air Purifiers Can’t Remove CO2

By now, it should be clear: standard air purifiers aren’t built to remove CO2. But why is that? Let’s break it down from a scientific and practical standpoint.

The Physics of Gas Molecules

CO2 is a gas, and gases behave very differently from particles. Air purifiers are designed to capture solid or liquid particles suspended in the air—like dust or mold spores. But CO2 molecules are free-moving and don’t stick to filters the way particles do. They zip right through HEPA and carbon filters without a second thought.

To remove CO2, you’d need a system that can chemically react with it or physically trap it at a molecular level. That’s not something a typical home air purifier can do.

Energy and Cost Limitations

Even if a purifier could remove CO2, it would require a lot of energy and specialized materials. CO2 removal systems used in industrial settings or spacecraft are complex, expensive, and consume significant power. Scaling that down for home use isn’t practical—or affordable.

Plus, CO2 is naturally present in outdoor air. Even if you could remove it indoors, it would just seep back in through windows, doors, and cracks. The only real solution is to bring in fresh air from outside.

Misleading Marketing Claims

Some air purifier brands claim their devices “improve air quality” or “reduce indoor pollutants”—which is true, but vague. They’re usually referring to particles, not gases like CO2. Unfortunately, this can lead to confusion. If you’re buying a purifier hoping to reduce CO2, you might end up disappointed.

The bottom line: air purifiers are excellent tools for certain problems, but CO2 isn’t one of them. Understanding their limits helps you make smarter choices about indoor air quality.

What Actually Works to Reduce Indoor CO2?

So if air purifiers don’t remove CO2, what does work? The good news is, there are simple, effective strategies you can use to keep CO2 levels in check.

Ventilation: The #1 Solution

The most effective way to reduce CO2 is to bring in fresh outdoor air. Open windows, use exhaust fans, or install a mechanical ventilation system. Even cracking a window a few inches can make a big difference.

For example, I started opening my bedroom window at night, even in winter. At first, I worried about the cold, but using a blanket and adjusting the opening helped. Within a week, I noticed I was sleeping better and waking up more refreshed—likely because CO2 levels dropped overnight.

Air Exchangers and Energy Recovery Ventilators (ERVs)

If you live in a cold or hot climate and don’t want to lose heat or cool air, consider an ERV or heat recovery ventilator (HRV). These systems bring in fresh air while recovering energy from the outgoing air. They’re especially useful in tightly sealed, energy-efficient homes.

An ERV can reduce CO2 levels significantly without spiking your energy bills. They’re more expensive than a window fan, but they’re a long-term investment in comfort and health.

CO2 Monitors: Know Your Levels

You can’t manage what you don’t measure. A CO2 monitor is a small device that tracks the concentration of CO2 in your home. They’re affordable (many under $100) and easy to use.

I bought one for my home office. It sits on my desk and gives me a real-time reading. When the number creeps above 1,000 ppm, I know it’s time to open a window or take a break outside. It’s been a game-changer for staying alert during long work sessions.

Houseplants: A Nice Bonus, But Not a Solution

You’ve probably heard that houseplants can “clean the air.” While they do absorb CO2 during the day through photosynthesis, the effect is minimal in a typical home. You’d need dozens—or even hundreds—of plants to make a noticeable dent in CO2 levels.

That said, plants are great for mood, humidity, and aesthetics. Just don’t rely on them to solve your CO2 problem.

When Might You Need More Than Ventilation?

For most people, ventilation is enough to manage CO2. But in some cases, you might need a more advanced solution.

High-Occupancy Spaces

Classrooms, conference rooms, and gyms can have very high CO2 levels due to the number of people. In these cases, mechanical ventilation systems with CO2 sensors can automatically increase airflow when levels rise.

Sealed Environments

In submarines, spacecraft, or cleanrooms, CO2 buildup is a serious issue. These environments use chemical scrubbers—like lithium hydroxide—to absorb CO2. But again, these aren’t practical for homes.

Emerging Technologies

Researchers are exploring new ways to capture CO2 from indoor air, including advanced filters and electrochemical systems. Some companies are even developing “CO2 air purifiers,” but these are still in early stages and not widely available.

For now, ventilation remains the most reliable and cost-effective method.

Air Purifiers vs. CO2: A Practical Comparison

To help you understand the difference, here’s a quick comparison of what air purifiers can and can’t do:

Air Quality Issue	Can Standard Air Purifiers Help?	Best Solution
Dust, pollen, pet dander	✅ Yes (HEPA filters)	HEPA air purifier
Smoke, odors, VOCs	✅ Yes (activated carbon)	Air purifier with carbon filter
Bacteria, viruses	✅ Partially (HEPA + UV)	HEPA purifier with UV-C
Carbon dioxide (CO2)	❌ No	Ventilation, ERV/HRV, CO2 monitor
Radon, formaldehyde	❌ Limited	Source control, ventilation, specialized filters

This table shows that air purifiers are powerful tools—but only for certain problems. CO2 isn’t one of them.

Final Thoughts: Making Smart Choices for Better Air

So, do air purifiers get rid of CO2? The answer is clear: no, they don’t. But that doesn’t mean they’re not worth having. If you struggle with allergies, asthma, or just want to breathe cleaner air, a good air purifier can make a real difference. Just don’t expect it to solve your CO2 problem.

The real key to healthy indoor air is balance. Use an air purifier to tackle particles and odors, but pair it with smart ventilation strategies to manage CO2 and other gases. Open a window when you can. Use exhaust fans in the kitchen and bathroom. Consider an ERV if you live in a tightly sealed home. And invest in a CO2 monitor so you know what’s really going on in your space.

At the end of the day, clean air isn’t just about gadgets—it’s about habits. By understanding what your devices can and can’t do, you can create a healthier, more comfortable environment for yourself and your family. And that’s something worth breathing easy about.

Frequently Asked Questions

Do air purifiers get rid of CO2 effectively?

Most standard air purifiers cannot remove carbon dioxide (CO2) because they are designed to filter pollutants like dust, pollen, and VOCs—not gases. CO2 requires specialized technology like molecular filters or CO2 scrubbers to capture.

Can HEPA air purifiers remove CO2 from the air?

No, HEPA filters only trap particulate matter, not gaseous CO2. While they improve air quality by removing allergens, they won’t reduce CO2 levels in a room.

What type of air purifier removes CO2?

To reduce CO2, you need air purifiers with activated carbon filters or systems like pressure swing adsorption (PSA). These technologies chemically bind to or absorb CO2 molecules, unlike standard filters.

Do air purifiers get rid of CO2 if I have poor ventilation?

Air purifiers alone can’t solve high CO2 levels caused by poor ventilation. Increasing airflow (e.g., opening windows) is the most effective way to dilute CO2, though some advanced purifiers may assist.

Why don’t regular air purifiers target CO2?

CO2 is a stable, non-toxic gas at normal levels, so most purifiers prioritize harmful pollutants. Removing CO2 also requires more energy-intensive processes, making it less common in consumer-grade units.

Are there air purifiers that get rid of CO2 for home use?

Yes, but they’re rare and expensive. Look for models with amine-functionalized filters or CO2 scrubbers, often used in industrial settings. For homes, improving ventilation is typically more practical.