Many people associate poor air quality with bad smells — but not all harmful air is noticeable. In fact, carbon dioxide (CO₂) is completely colorless and odorless, even at high concentrations.

That makes it invisible and undetectable to human senses — and that’s exactly what makes it so risky in enclosed spaces.

🧪 What Is CO₂?

Carbon dioxide is a natural gas produced by:

• Human and animal respiration
• Combustion (e.g., engines, cooking)
• Fermentation, industrial processes

In outdoor air, CO₂ levels are typically around 420 ppm (parts per million) — completely safe. But in closed environments like cars, bedrooms, offices, or classrooms, CO₂ can rise quickly due to human breathing, especially when ventilation is poor.

😴 The Hidden Effects of CO₂ Buildup

Because CO₂ has no smell, no taste, and no color, people don’t realize when it’s accumulating. But even without a warning smell, high CO₂ levels can cause:

• Drowsiness and fatigue
• Headaches
• Difficulty concentrating
• Increased heart rate and discomfort
• Reduced decision-making performance

These symptoms typically start when CO₂ levels exceed 1000–1500 ppm — a common situation in closed cars or poorly ventilated rooms.

🚗 Why It Matters in Cars

Inside a vehicle with the windows closed and air conditioning set to recirculation mode, CO₂ levels can exceed 2000 ppm in under an hour — especially with multiple passengers.

And because it doesn’t smell bad, you’d never know — until you start feeling tired, groggy, or lightheaded.

✅ The Solution: Measure What You Can’t Smell

That’s why a CO₂ meter is essential. Since you can’t smell CO₂, the only way to know if the air is fresh and safe is to monitor it with a sensor. <div style=”text-align:center;”> <img src=”https://your-image-link.com/co2-meter.jpg” alt=”CO2 meter image” width=”60%”> <p style=”font-size:14px;”>Our EvoDevice CO₂ meters track invisible CO₂ buildup in real time — helping you stay alert and safe.</p> </div>

📌 In Summary

• CO₂ is odorless, colorless, and tasteless — it gives you no warning signs.
• It can accumulate in cars, bedrooms, meeting rooms, or anywhere ventilation is limited.
• A CO₂ monitor is the only reliable way to stay aware and take action.

If you can’t smell it, you can’t manage it. Let EvoDevice help you measure what matters.

When you’re sitting in a car with the windows closed and the air conditioning set to recirculation mode, it’s easy to assume that the air is clean and safe — especially if the temperature feels comfortable. But in reality, carbon dioxide (CO₂) levels can rise rapidly, even with just one person inside.

Here’s Why:

1. The same air is being reused.
Recirculation mode means the HVAC system is only reusing the air already inside the car — no fresh air from outside is being introduced. While this helps maintain temperature, it also traps exhaled gases, including CO₂.

2. Human breathing produces a lot of CO₂.
An average adult exhales about 0.3 to 0.4 liters of CO₂ per minute. In a sealed vehicle, this CO₂ accumulates quickly — especially with multiple passengers.

3. CO₂ levels can exceed 2000 ppm within 20–40 minutes.
Many tests have shown that in recirculation mode:

• CO₂ can reach 1500–2000 ppm in under 20 minutes with just one person.
• With more passengers, levels may exceed 3000 ppm, which can cause drowsiness, headaches, and reduced concentration — dangerous during long drives.

What You Can Do:

• Switch to fresh air (outside air) mode every 8–16 minutes.
• Crack a window slightly to allow natural air exchange.
• Use a CO₂ meter to monitor cabin air quality, especially during long commutes or group travel.

Final Thoughts:

Comfortable temperature ≠ clean air.
Even if the cabin feels perfect, poor ventilation can lead to high CO₂ levels that affect your alertness and well-being. Understanding how recirculation works — and when to switch it off — is key to a safer, healthier driving experience.

It is currently the most mainstream, accurate, and stable method for measuring CO₂ levels.

🔬 How It Works in Detail:

🔹 1. Each gas absorbs infrared light at specific wavelengths

CO₂ molecules strongly absorb infrared light at a wavelength of 4.26 micrometers.
This is similar to how sunglasses block certain colors of light — CO₂ “blocks” a specific band of infrared light.

🔹 2. Core Structure of an NDIR Sensor:

ComponentFunction DescriptionInfrared Light SourceEmits infrared light around 4.26 μmGas ChamberAllows air (containing CO₂) to pass throughOptical FilterOnly allows CO₂-specific infrared wavelengths to passPhotodetectorDetects the intensity of transmitted infrared lightMicrocontrollerConverts light intensity change into a CO₂ ppm reading

🔹 3. Measurement Flow (can be visualized in a diagram):

Infrared source → emits IR light → passes through air chamber → CO₂ absorbs part of it → reaches detector →
weakened signal → microcontroller calculates CO₂ concentration

📊 Example:

• The higher the CO₂ concentration, the more infrared light is absorbed.
• The weaker the light reaching the detector → the higher the CO₂ level.
• The final ppm reading is calculated based on this absorption.

✅ Summary of Advantages:

FeaturePerformanceHigh Accuracy±50 ppm or betterExcellent StabilityMinimal long-term driftNo Cross-Gas InterferenceUnaffected by water vapor or VOCsNo Chemicals or ConsumablesLong lifespan, maintenance-free

www.amazon.com/evodevice

1. CO₂ molecules are too small — no mask can stop their diffusion

N95, KN95, and surgical masks have filter pore sizes around 0.3 microns.
CO₂ molecules, however, are only ~0.00033 microns in diameter — far too small to be blocked.

Even when wearing a mask, exhaled CO₂ still enters the surrounding air, leading to rising concentrations.

2. The feeling of “stuffy air” isn’t due to less CO₂, but rather more of your own exhaled CO₂

Inside a sealed mask area, CO₂ can reach over 5000 ppm, much higher than the surrounding air.
While this doesn’t significantly affect overall CO₂ in the car, you’ll feel more fatigued and dizzy.

📊 Real-world research (great for awareness)

According to Japan’s Traffic Safety Research Center:

• A driver wearing a mask vs. not wearing a mask showed no significant difference in CO₂ levels inside a closed car after 30 minutes.
• In fact, multiple people wearing masks while talking or breathing heavily reduced the likelihood of opening windows, causing CO₂ levels to rise faster.

❌ Common Misconceptions

Claim: “Wearing a mask reduces the amount of CO₂ you exhale into the air.”

❌ False

Explanation: CO₂ passes through the mask almost completely.

Claim: “Masks can absorb CO₂.”

❌ False

Explanation: Mask filters aren’t designed to absorb gas molecules.

Claim: “Wearing a mask makes the air feel cleaner.”

⚠ Misleading. Actually, CO₂ builds up inside the mask and makes breathing harder.

✅ What You Should Do:

• Monitor CO₂ levels in real time
• When CO₂ exceeds 1200–1400 ppm, try: Briefly switching to outside air mode. Rolling down the windows for ventilation. Avoiding long periods of sealed recirculation with multiple passengers

www.amazon.com/evodevice

When the Tesla Model 3 is in automatic air conditioning circulation mode, it automatically switches to internal circulation after the carbon dioxide concentration exceeds 1,600. We can see that the carbon dioxide concentration starts to drop, but the rate of decrease is very slow. Hoping to reduce the carbon dioxide concentration more quickly, we manually turned on the external circulation, and at this point, the carbon dioxide concentration quickly dropped to a safe level.

http://www.amazon.com/evodevice

We often think about road safety in terms of distractions, fatigue, or even bad weather. But there’s one hidden factor that rarely gets mentioned — yet it affects millions of drivers every day:

Carbon Dioxide (CO₂) buildup inside your car.

You can’t see it. You can’t smell it. But its effects are real — and scientifically proven.

🚗 What Happens When CO₂ Builds Up in a Car?
When you breathe, you exhale CO₂. In an enclosed space like a car — especially with the windows closed and the AC on recirculate — CO₂ can accumulate surprisingly fast.

The more passengers, the faster the buildup.

And while CO₂ isn’t toxic like carbon monoxide (CO), it affects your brain and body in subtle but dangerous ways.

🔬 CO₂ Levels and Their Impact on the Human Body (Backed by Research)
400–800 ppm, feels fresh and comfortable.

800–1000 ppm, Mild stuffiness, slight decline in focus.

1000–1500 ppm, Reduced attention span, slower reaction time, light fatigue begins.

1500–2000 ppm, Noticeable drowsiness, headaches, yawning, irritability. Severe fatigue, impaired judgment, increased risk of error

5000 ppm, Possible hypoxia, nausea, vomiting, risk of fainting — dangerous driving conditions

Source: Indoor air quality research and vehicle cabin environment studies (ASHRAE, Harvard School of Public Health, etc.)

🚦 Why It Matters for Drivers
At just 1500 ppm, you may start yawning.
At 2000+ ppm, your brain function slows down significantly — not enough to make you notice immediately, but enough to impair your judgment, reaction time, and decision-making behind the wheel.

You may feel “tired for no reason” or “mentally foggy” while driving, even if you’re well rested.
CO₂ could be the silent cause.

✅ How to Reduce CO₂ While Driving
Switch AC from “recirculation” to “fresh air” mode regularly

Crack a window, even a small opening makes a big difference

Avoid long periods of idling with windows up

Use a CO₂ monitor to understand your in-cabin air quality

Take breaks and get fresh air on longer drives

Final Thoughts
We talk a lot about distracted driving and fatigue. But there’s another kind of fatigue that creeps up invisibly — caused by the very air we breathe inside our cars.

If you’re driving for long periods — especially with others — CO₂ may be quietly compromising your alertness and safety.

It’s time we paid more attention to what’s in our air, not just how fast we’re moving through it.

http://www.amazon.com/evodevice