Do Air Purifiers Get Rid of Carbon Dioxide Effectively

Most air purifiers do not effectively remove carbon dioxide (CO₂), as standard filters like HEPA and activated carbon target pollutants such as dust, allergens, and VOCs—not CO₂. Only specialized systems with CO₂ scrubbers or ventilation integration can significantly reduce carbon dioxide levels, making standalone air purifiers a poor solution for high-CO₂ environments.

Key Takeaways

• Air purifiers do not remove carbon dioxide because they are designed for particles, not gases.
• CO2 reduction requires ventilation—open windows or use HVAC systems to exchange stale indoor air.
• HEPA filters capture pollutants like dust and allergens but not carbon dioxide molecules.
• Activated carbon filters absorb odors and VOCs but have limited impact on CO2 levels.
• Monitor indoor CO2 with detectors to assess air quality and know when to ventilate.
• Improve air exchange regularly to maintain safe CO2 levels in enclosed spaces.

Do Air Purifiers Get Rid of Carbon Dioxide Effectively

Let’s be honest—most of us think about air purifiers when we’re sneezing from pollen, worried about pet dander, or trying to keep our homes smelling fresh. But what about something invisible, odorless, and constantly being produced in our homes just by breathing? That’s carbon dioxide, or CO₂. It’s a natural byproduct of human respiration, and while it’s not toxic at normal levels, too much of it can make you feel sluggish, drowsy, or even give you a headache—especially in tightly sealed, poorly ventilated spaces.

I remember the first time I noticed it. I was working from home in my small, cozy office with the windows shut and the door closed. After a few hours, I started feeling foggy, like I couldn’t focus. I blamed it on screen fatigue or lack of coffee. But then I started paying attention—my energy would dip every afternoon, right around the time I’d been sitting still for hours. A quick search led me to CO₂ buildup. That’s when I started wondering: Do air purifiers get rid of carbon dioxide? I bought one, set it up, and waited. Spoiler alert: it didn’t fix the problem. But it did lead me down a rabbit hole of research that changed how I think about indoor air quality.

Understanding Carbon Dioxide: What It Is and Why It Matters

Before we dive into whether air purifiers can tackle CO₂, let’s get clear on what carbon dioxide actually is. CO₂ is a colorless, odorless gas that’s naturally present in the atmosphere. We exhale it every time we breathe, and it’s also produced by burning fuels, cooking, and even houseplants at night (yes, really). In outdoor environments, CO₂ levels typically hover around 400–450 parts per million (ppm). But indoors, especially in energy-efficient homes with limited airflow, levels can easily climb to 1,000 ppm or higher.

How CO₂ Builds Up Indoors

Think about your home on a cold winter day. Windows are shut, the heating system is running, and maybe you’ve got a fireplace going. It’s cozy, but it’s also trapping everything inside—including the CO₂ you’re breathing out. The same thing happens in offices, classrooms, and even cars. Without proper ventilation, CO₂ accumulates. And unlike pollutants like smoke or dust, CO₂ doesn’t settle or get filtered out easily. It just keeps building up.

Health Effects of Elevated CO₂ Levels

You might be wondering, “Is a little extra CO₂ really that bad?” The short answer: it depends on the concentration. At levels between 600–1,000 ppm, most people don’t notice any issues. But once you hit 1,000–2,000 ppm, symptoms start to appear. These can include:

• Headaches
• Drowsiness or fatigue
• Difficulty concentrating
• Increased heart rate
• Shortness of breath in sensitive individuals

At extremely high levels (above 5,000 ppm), CO₂ can become dangerous, but that’s rare in typical home environments. Still, even moderate increases can impact cognitive performance. A Harvard study found that people working in environments with CO₂ levels around 950 ppm scored significantly lower on decision-making tests compared to those in cleaner air.

Common Sources of Indoor CO₂

So where does all this CO₂ come from? Here are the usual suspects:

• Human respiration: Just breathing adds CO₂ to the air. The more people in a room, the faster it builds up.
• Cooking: Gas stoves and ovens release CO₂ as a byproduct of combustion.
• Fireplaces and space heaters: Any fuel-burning appliance contributes to CO₂ levels.
• Houseplants at night: While plants absorb CO₂ during the day through photosynthesis, they release it at night during respiration.
• Poor ventilation: Modern homes are built to be airtight for energy efficiency, which means less fresh air exchange.

Understanding these sources is the first step in managing indoor CO₂. But the big question remains: can an air purifier help?

How Air Purifiers Work: What They’re Designed to Do

To answer whether air purifiers get rid of carbon dioxide, we need to understand how they actually work. Most air purifiers on the market today use one or more of the following technologies: HEPA filters, activated carbon filters, UV-C light, ionizers, or electrostatic precipitators. Each has a specific job, but none are designed to remove CO₂.

HEPA Filters: The Gold Standard for Particles

HEPA (High-Efficiency Particulate Air) filters are the most common and effective type for removing airborne particles. They can capture 99.97% of particles as small as 0.3 microns—things like dust, pollen, mold spores, pet dander, and even some bacteria and viruses. But here’s the catch: CO₂ molecules are about 0.33 nanometers in size. That’s thousands of times smaller than what a HEPA filter can trap. So while HEPA filters are fantastic for cleaning the air of allergens and pollutants, they do nothing for carbon dioxide.

Activated Carbon Filters: Great for Odors, Not for CO₂

You might think activated carbon filters could help, since they’re great at absorbing gases and odors—like smoke, cooking smells, or VOCs (volatile organic compounds). And you’re right—they’re excellent for those things. But CO₂ is a stable, non-reactive gas. It doesn’t bind well to carbon surfaces, especially at the low concentrations found in homes. So while activated carbon can help with some gaseous pollutants, it’s not effective for reducing CO₂ levels.

Other Technologies: UV-C, Ionizers, and More

Some air purifiers use UV-C light to kill bacteria and viruses, or ionizers to charge particles so they stick to surfaces. Others use ozone generators (which we don’t recommend due to health risks). But none of these technologies target CO₂. UV light doesn’t break down CO₂ molecules. Ionizers don’t remove gases. And ozone? That’s a whole other problem—it can irritate the lungs and doesn’t reduce CO₂.

Real-World Example: My Air Purifier Experiment

When I first got my air purifier, I was hopeful. I set it up in my office, turned it on high, and monitored CO₂ levels with a cheap sensor I bought online. Over the course of a day, with the door closed and no ventilation, CO₂ levels climbed from 500 ppm to over 1,200 ppm. I ran the purifier for 6 hours straight. The particle count dropped, the air felt cleaner, but the CO₂ level? Still over 1,200 ppm. The purifier was doing its job—just not the job I thought it was doing.

This experience taught me an important lesson: air purifiers are powerful tools, but they’re not magic. They’re designed to clean the air of particles and some gases, not to manage CO₂. If you’re looking to reduce carbon dioxide, you’ll need a different approach.

The Truth About Air Purifiers and CO₂ Removal

So, do air purifiers get rid of carbon dioxide? The straightforward answer is no. Standard consumer air purifiers—whether they use HEPA, carbon, UV, or ionization—are not equipped to remove CO₂ from the air. They simply weren’t designed for that purpose. CO₂ is a dissolved gas, not a particle, and it doesn’t respond to filtration or ionization in the way that dust or smoke does.

Why CO₂ Is Different from Other Pollutants

To understand why air purifiers can’t handle CO₂, it helps to compare it to other common indoor pollutants. Let’s break it down:

Pollutant Type	Size/Form	Can Air Purifiers Remove It?	Example
Particles	0.3–10 microns	Yes (with HEPA)	Dust, pollen, pet dander
Gases & Odors	Molecular	Yes (with activated carbon)	VOCs, smoke, cooking smells
Carbon Dioxide (CO₂)	0.33 nanometers (gas)	No	Breathing, gas stoves
Bacteria & Viruses	0.1–5 microns	Sometimes (HEPA or UV)	Flu virus, mold spores

As you can see, CO₂ falls into a category of its own. It’s a gas, but not one that reacts well with filters or ionization. It’s also naturally occurring and essential to life—we need some CO₂ in the air. The problem isn’t the gas itself, but the concentration in enclosed spaces.

Misconceptions and Marketing Claims

Unfortunately, some air purifier brands blur the lines. You might see ads claiming their products “clean the air” or “remove harmful gases,” which can lead people to believe they’re tackling CO₂. But unless a purifier specifically mentions CO₂ removal (and even then, you should be skeptical), it’s not doing that job. Always read the fine print. Look for third-party testing and certifications like AHAM or CADR ratings, which measure performance for particles, not gases like CO₂.

What Air Purifiers Can Do for Your Indoor Air

Just because air purifiers don’t remove CO₂ doesn’t mean they’re useless. In fact, they’re incredibly helpful for improving overall air quality. Here’s what they can do:

• Reduce allergens like pollen, dust mites, and pet dander
• Capture mold spores and some bacteria
• Neutralize odors from cooking, pets, or smoke
• Lower levels of VOCs when equipped with activated carbon
• Improve sleep and reduce allergy symptoms

So while they won’t solve your CO₂ problem, they can make your home feel fresher and healthier in other ways. Think of them as part of a broader air quality strategy—not a standalone solution.

Effective Ways to Reduce Carbon Dioxide Indoors

If air purifiers can’t remove CO₂, what can you do? The good news is that there are several proven, practical ways to lower indoor CO₂ levels. The key is increasing ventilation and managing sources. Here are the most effective strategies:

1. Increase Ventilation

The single most effective way to reduce CO₂ is to bring in fresh outdoor air. This dilutes the concentration of CO₂ and other indoor pollutants. Here’s how:

• Open windows: Even just cracking a window for 10–15 minutes a few times a day can make a big difference.
• Use exhaust fans: Turn on bathroom and kitchen fans to pull stale air out and draw fresh air in.
• Install a heat recovery ventilator (HRV) or energy recovery ventilator (ERV): These systems exchange indoor and outdoor air while retaining heat or coolness, making them energy-efficient and effective.

2. Monitor CO₂ Levels

You can’t manage what you don’t measure. A CO₂ monitor is a small investment (many cost under $100) that can give you real-time feedback on air quality. Place one in your bedroom, office, or any frequently used room. Aim to keep levels below 1,000 ppm. If they consistently rise above that, it’s a sign you need more ventilation.

3. Limit Occupancy in Small Spaces

The more people in a room, the faster CO₂ builds up. If you’re in a small meeting room, classroom, or home office, try to limit the number of people or take breaks outside. Even stepping out for 5 minutes can help reset the air.

4. Avoid Unnecessary Combustion

Gas stoves, fireplaces, and space heaters all add CO₂ to the air. Use them sparingly, and always ensure proper ventilation when they’re in use. Consider switching to electric appliances where possible.

5. Add Houseplants (With a Caveat)

Plants absorb CO₂ during the day, so they can help a little—but don’t expect miracles. You’d need a lot of plants to make a noticeable difference. Plus, they release CO₂ at night, so they’re not a complete solution. Still, they’re great for improving humidity and adding a touch of nature.

6. Use a CO₂ Scrubber (For Extreme Cases)

In rare cases—like in submarines, spacecraft, or tightly sealed labs—specialized CO₂ scrubbers are used. These devices use chemicals like lithium hydroxide or sodium hydroxide to absorb CO₂. But they’re expensive, complex, and not practical for home use. For most people, ventilation is the best and simplest solution.

Combining Air Purifiers with Other Strategies for Better Air Quality

Now that we know air purifiers don’t remove CO₂, how can we use them effectively as part of a larger air quality plan? The answer is simple: combine them with ventilation and monitoring for a comprehensive approach.

Create a Layered Air Quality Strategy

Think of indoor air quality like layers of protection. Air purifiers handle particles and some gases. Ventilation tackles CO₂ and brings in fresh air. Monitoring gives you feedback. Together, they create a healthier environment. For example:

• Use an air purifier with a HEPA filter in your bedroom to reduce allergens while you sleep.
• Open windows in the morning to flush out CO₂ buildup from the night.
• Keep a CO₂ monitor on your desk to alert you when levels rise during the day.
• Run the kitchen exhaust fan while cooking to remove both odors and combustion byproducts.

Choose the Right Air Purifier for Your Needs

Even though air purifiers don’t remove CO₂, choosing the right one can still make a big difference. Look for:

• A true HEPA filter (not “HEPA-type”)
• Activated carbon for odor and VOC control
• A CADR rating appropriate for your room size
• Low noise levels for bedrooms or offices
• Energy-efficient operation

Brands like Levoit, Coway, and Blueair offer reliable models that balance performance and price. Just remember: no matter how good the purifier, it won’t fix high CO₂ levels on its own.

When to Call in the Pros

If you’ve tried ventilation and monitoring but still have consistently high CO₂ levels, it might be time to consult an HVAC professional. They can assess your home’s airflow, recommend ventilation upgrades, or install an ERV/HRV system. This is especially important in newer, energy-efficient homes that are nearly airtight.

Final Thoughts: Managing CO₂ for a Healthier Home

So, do air purifiers get rid of carbon dioxide? The answer is clear: no, they don’t. But that doesn’t mean they’re not valuable. Air purifiers are excellent tools for removing particles, allergens, and odors—just not CO₂. To manage carbon dioxide effectively, you need to focus on ventilation, monitoring, and smart habits.

Think of it this way: air purifiers clean the air, but they don’t refresh it. For that, you need fresh air from outside. By combining both approaches, you can create a home that’s not only clean but also comfortable and energizing. Whether you’re working, sleeping, or just relaxing, good air quality starts with understanding what’s in your air—and knowing how to manage it.

Next time you feel that mid-afternoon slump, don’t just reach for another cup of coffee. Check your CO₂ levels. Open a window. Take a breath of fresh air. Your brain—and your body—will thank you.

Frequently Asked Questions

Do air purifiers get rid of carbon dioxide effectively?

Most standard air purifiers are not designed to remove carbon dioxide (CO2) from the air. They focus on filtering particles like dust, pollen, and VOCs, but CO2 requires specialized technology such as molecular filters or ventilation systems to reduce levels effectively.

Can air purifiers help with high CO2 levels in a room?

Air purifiers with activated carbon or molecular filtration may slightly reduce CO2, but they are not efficient for significant CO2 removal. Proper ventilation or dedicated CO2 scrubbers are far more effective solutions for lowering carbon dioxide concentrations.

What type of air purifier removes carbon dioxide?

To remove carbon dioxide, you need an air purifier with advanced molecular filters, such as those using amine-functionalized materials or pressure swing adsorption. Standard HEPA or carbon filters found in most purifiers cannot capture CO2 effectively.

Do air purifiers get rid of carbon dioxide as well as odors?

While air purifiers with activated carbon excel at trapping odors and volatile organic compounds (VOCs), they do not target carbon dioxide. CO2 requires different technologies, so relying on a purifier for this purpose is not practical.

Is it necessary to remove carbon dioxide with an air purifier?

In most homes, CO2 levels are not high enough to pose health risks, so removing it isn’t a priority. Instead, focus on ventilation or plants to naturally regulate CO2, while using air purifiers for pollutants like allergens and smoke.

How can I reduce carbon dioxide without a specialized air purifier?

Opening windows, using exhaust fans, or adding indoor plants are natural ways to lower CO2. For extreme cases, consider energy recovery ventilators (ERVs) or dedicated CO2 scrubbers instead of relying on standard air purifiers.