Handheld CO2 Meter (ppm)

Model: FD-90A-CO2-PPM
User Manual: Click Here
Blog Article: Click Here


  • ⚛️ DETECT: Single-gas detector for carbon dioxide, 0 - 5000ppm with 1ppm resolution. Comes FACTORY-CALIBRATED.
  • 🔋ACCURACY: Dual Beam NDIR sensor with accuracy: ≤ 5% F.S. and response time: T < 30 sec. Zero and span calibration options.
  • 🎆 ALARMS: Adjustable audio, visual, and vibration alarms alert when preset levels are reached.
  • 💪 STRONG: Shockproof, water-resistant, dust-proof, and explosion-proof.
  • 🕵️ TRUSTWORTHY: 1-year limited warranty. Product tested and verified in the USA.

Technical Specifications

Carbon dioxide (CO2) detection: 0 - 5000 with 1ppm resolution
Accuracy: ≤ ± 5% F.S
Response time: T < 30 sec
Indication: LCD indicates the time, concentration, temp, and battery state
Alarm: Indication of alarm, fault, and low voltage with LED, sound, vibration
Operating temperature: 0F - 122F
Humidity: < 95% RH non-condensing
Operating voltage: DC 3.7V Li-battery, 1500 mAh
Working time: > 24 hours
Charging time: 4 hours
Sensor life: up to 7 years
Protection category: IP65
Weight: about 130g (including battery)
Calibration: USA NIST Traceable Gas Source

Video Tutorial

In the Box?

  • CO2 Meter
  • English user manual
  • USB Charging Cable
  • Belt Clip and Sling
  • Calibration Cap Cover
  • USA NIST Calibration Certificate
  • USA Technical Support
carbon dioxide CO2 package ppm levels in air
APPLICATIONS - CO2 Indoor Air Quality
- CO2 Work Occupational Exposure
- CO2 for Confined Spaces
- CO2 Inspection and Assessment
- CO2 for Restraurants, Breweries, Hydroponics, Grow Rooms

Best Handheld CO2 Meter

We present an ideal CO2 handheld meter to track and report your CO2 indoor air quality while providing personal protection alarming. Constructed for professionals in mind such as industrial technicians that are looking to detect CO2 with a robust personal CO2 meter they can clip on their pants and shirt, or hold and take precise CO2 air quality measurements. This unit is also available as a CO2 0-10% version and a CO2 0-100% version.

This handheld CO2 meter is different from the desktop CO2 equivalent since it is made with a more robust design to be used by trade professionals and is designed to be a fully handheld operated unit with full calibration features to enable super high accuracy.

CO2 Meter Carbon Dioxide

CO2 Meter Comparison Chart

We offer a variety of CO2 meters and analyzers. Here we show a comparison chart of some of them to highlight key CO2 meter differences.

carbon dioxide meter comparison chart

Why is CO2 important for Indoor Air Quality?

Academic studies are showing evidence that elevated levels of CO2 in indoor spaces, specifically below 5,000 ppm, could directly impact human health. Increasing background or outdoor CO2 is not helping. The increasing concentration of atmospheric CO2 may lead to more frequent and prolonged exposure indoors due to higher indoor air concentrations and increased indoor time.

Human health risks include inflammation, impaired higher-level cognitive abilities, bone demineralization, kidney calcification, oxidative stress, and endothelial dysfunction. Surprisingly, even at CO2 exposures as low as 1,000 ppm, there seem to be potential health concerns. The 1,000 ppm threshold is often surpassed in many indoor environments with overcrowding and insufficient building ventilation rates.

It is evident that continuous exposure to elevated atmospheric CO2 could become an underestimated stressor in the modern and future environment and does not seem to abate. If anything, CO2 will continue to amplify in importance and the need to handheld CO2 meter will further increase in demand.

Carbon Dioxide in a Confined Space such as a Train
Carbon Dioxide accumulation in a Confined Space such as a Train.

Case Study: CO2 Air Quality in A Hospital

The concentration of carbon dioxide in outdoor air is around 400 parts per million (ppm). In comparison, the human exhaled CO2 breath is about  40,000 ppm (4% vol).

This significant difference in CO2 levels between pure fresh outdoor CO2 air and human exhaled breath highlights the requirement and importance of proper indoor ventilation. Specifically, ventilation in occupied spaces where pathogens can be prevalent such as a hospital or clinic scenario.

HOSPITAL CO2 LEVELS REQUIREMENTS (FRESH AIR) Most hospitals maintain ventilation requirements of 2 air changes of outdoor air per hour in accordance with the American Institute of Architects and American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommendations. This is important to ensure pathogens are continuously diluted with fresh non-polluted air.

When comparing healthcare facilities to residential and commercial buildings, the risk of airborne transmission is lower in healthcare settings due to the specific requirements for increased ventilation.

The good news is that in recent studies using CO2 meters focusing on COVID-19 wards, the levels of carbon dioxide consistently remained below 800 ppm, indicating adequate ventilation. However, some investigations have shown elevated carbon dioxide levels in hospitals, especially in areas with high room occupancy.

Furthermore, airborne pathogen transmission in healthcare facilities often occurs in ancillary care and outpatient areas where ventilation might not be optimal. Exposures also frequently happen in places like breakrooms, which can be a concern for infection spread.

To address these ventilation concerns a unique study was investigated. Carbon dioxide levels were monitored in various settings throughout an acute care hospital.

CO2 Levels In a Conference Room Located in a Hospital
CO2 Levels In a Conference Room Located in a Hospital Monitored using a Handheld CO2 Meter
CO2 Levels In a Office Room Located in a Hospital Monitored using a Handheld CO2 Meter
CO2 Levels In a Office Room Located in a Hospital Monitored using a Handheld CO2 Meter
CO2 in a Hospital Waiting Room
CO2 Levels can rise and the Probability of pathogen transmission can be high in Hospital Waiting Rooms.
Handheld CO2 Meter
Handheld CO2 Meter detecting Carbon Dioxide Gas.

CO2 Levels in Various Parts of a Hospital

Location (volume m3) Peak carbon dioxide level (ppm) Peak # people present Time period monitored
Main lobby 577 75 12 h (7 AM-5 PM)
Cafeteria 756 68 12 h (7 AM-5 PM)
Physical therapy 552 14 12 h (7AM-5 PM)
Emergency department* 701 20 12 h (7AM-5 PM)
Elevators (N = 2) (8.5 m3) 638 1 to 6 20 min
Large conference room (55.5 m3) 638 37 60 min
Small conference room (31 m3) with overcrowding 1246 8 60 min
Small conference room (31 m3) without overcrowding 774 4 60 min
Breakrooms (N = 2) (52 m3) ≤628 3 20 min
Office #1 (38.5 m3) 1226 3 24 min
Offices (N = 4) (24.8 m3) ≤788 3 24 min
Inpatient rooms (N = 5) (43 m3) ≤567 2 20 min
Outpatient clinic rooms (N = 5) (24 m3) ≤709 3 20 min
Bathrooms in patient care area (N = 3) ≤636 2 10 min
Bathroom in patient care area (N = 1) 908 2 10 min
CONCLUSION (CASE STUDY CO2 LEVELS IN HOPSITALS) - During the testing conducted in five offices, the carbon dioxide levels consistently stayed below 800 ppm when the door was open and there were 2 or 3 people present. Only one office experienced levels exceeding 800 ppm.
- In one bathroom the carbon dioxide level rose to 908 ppm even with two people present, and they were spaced at least 1.8 meters apart.
- The good news is that in both inpatient rooms and outpatient clinic rooms with an air exchange rate of 6-9 air changes per hour (ACH), the carbon dioxide levels remained below 800 ppm when there were 2-3 people present. This suggests that the ventilation in these areas was effective in maintaining low carbon dioxide levels even with the presence of occupants.

Are Cheap CO2 Meters Accurate?

CO2 Meter accuracy is not dependent on the actual cost of the CO2 meter. In fact, there are many very cheap units that work excellent. The most critical part of a CO2 gas meter accuracy is correct CALIBRATION. Yes, calibration. You can think of calibration as the fine "tuning" process of making a CO2 meter read accurately. If the tuning or calibration process is not done to USA NIST traceable gas sources, then your expensive or cheap meter (irrelevant of cost), will not be accurate!

How can I test my CO2 levels at home?

To test home CO2 levels, you need a handheld CO2 meter. These units all vary in features, but the Handheld CO2 meter here is small and easy to operate with one hand to take your CO2 levels in different parts of your home.

What is it Lacking?

  1. NO CO2 DATALOGGING: In order to reduce costs, we decided not to include CO2 data logging features. Since less than 5% of customers expressed interest in this functionality, it didn't make sense for the remaining 95% to pay for a feature they do not want. The additional expenses primarily stem from the need for more microchips to enable memory functionality.
  2. NO CO2 LIVE GRAPHING: We made a deliberate choice not to incorporate CO2 live graphing on the front screen. While some may find it "novel" and "neat," we discovered that it tends to clutter the display and make it complicated to read. In essence, it becomes distracting. Instead, we opted for larger CO2 digits to provide a quick and easy CO2-level reading, which most users prioritize.
  3. NO DIGITAL COMMUNICATION: The CO2 meter lacks Bluetooth or WiFi communication capability. Due to the low demand for this feature (less than 3% of customers), we decided against including it to keep costs down. Adding Bluetooth and WiFi chipsets would have incurred additional expenses, which we chose to avoid to ensure affordability for our customers.
  4. NO USB CHARGER: To reduce packaging, size, and cost, our CO2 meter does not come with a USB charger, but it includes a USB cable. We recognize that most people already have USB block chargers or adapters at home and in their computer ports. Including an extra USB charger would have been unnecessary. However, if someone truly requires one, they can reach out to us, or they can easily purchase one online for a nominal price. We also believe in minimizing waste and saving resources, hence the decision not to include an extra charger.
  5. NO PUMP: Unlike some CO2 analyzer reading in ppm units that have a built-in pump to force air to the sensor. This handheld CO2 meter does not include a pump feature as it is not intended for use with a probe or external air sampling.
Gas Meter Design

What is the Lifetime of a CO2 NDIR Sensor and a O2 sensor?

CO2 NDIR (Non-Dispersive Infrared) sensors exhibit remarkable durability as they are solid-state components, capable of lasting between 5 to 15 years. The primary component to monitor in these sensors is the IR source, which, although it rarely occurs, may degrade or fail completely. Nevertheless, NDIR sensors are impressive inventions, and their prices have significantly decreased over the past decade due to advancements in micromachining and the miniaturization of electronic components.

In contrast, O2 sensors are of the electrochemical type and not solid-state. They rely on ionic conduction involving a mixture of electroactive solutions. As a consequence, O2 sensors are quite delicate and typically last between 2 to 3 years. Time is the main factor responsible for their degradation, but it's important to note that these sensors may also leak acid, which can lead to the corrosion of sensor plug connections and other electronics in your analyzer. To ensure accurate readings and avoid potential damage, frequent calibration and regular inspections of O2 sensors are crucial.

FUN FACT! Did you know CO2 is heavier than air? For consistent comparison results, it is always best practice to take CO2 measurements at the same height whenever comparison room-to-room measurements. Make sure you are consistent when indoor air quality monitoring.

How often must I Calibrate my Handheld CO2 Monitor?

We recommend calibrating between 6 to 12 months. Now please don't forget, gas calibration is all about accuracy. The more often you calibrate, the more accurate your CO2 meter will be reading. Our company offers a CO2 gas calibration service or you can do it yourself with a calibration kit that consists of the following items:

Calibration Kit
Calibration Gas (CO2)
Calibration Gas Regulator (C10)

Best CO2 Detectors

How long will the CO2 Monitor Last?

The good news is that CO2 monitors boast impressive longevity when compared to other gas sensors, like electrochemical cells. They rely on NDIR (Non-Dispersive Infrared) sensors, which are solid-state electronic components known for their extended lifespan, typically lasting between 5 to 15 years. Among these components, the infrared source tends to be the most vulnerable, as it may gradually degrade over time. Hence why we recommend annual calibration.

What is a good CO2 level indoors?

Different agencies provide recommended "good" CO2 levels. But to start with, we must understand that lower is better, and higher is worse. For example, the outdoor CO2 levels is the "freshest" CO2 levels that exist and hover at about 410 ppm. When humans are indoors, due to breath and exhalation this CO2 level increases and gets worse with time (all things being equal). Some examples of permissible CO2 concentration levels are as follows:

California State Assembly Bill AB841:
- Requirement: Classrooms must have CO2 monitors that trigger an alarm at 1,100 ppm.

American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE):
- Recommendation: Indoor CO2 concentrations in schools should be maintained below 1,000 ppm and below 800 ppm in offices.

German Federal Environment Agency:
- Recommendation: CO2 levels in classrooms and offices should be kept below 1,000 ppm.

Occupational Safety and Health (OSHA):
- Recommended 8-hour Time-Weighted Average (TWA) exposure limit: 5,000 ppm.

How Should I Store my CO2 Monitor?

For optimal sensor lifespan and precise measurements during operation, it is advised to store the CO2 monitor in a controlled environment with a humidity level of 50% RH and a room temperature of approximately 70°F.


  • A Handheld CO2 meter is an imperative tool to inspect and monitor indoor air quality.
  • CO2 meters are widely used in various inspection instances to monitor like classrooms, gyms, workplaces, and offices.
  • CO2 meters serve as an excellent indicator of pathogen transmission risk.
  • When CO2 levels reach over 1000 ppm they can have negative effects on humans.
  • BEWARE: Do not confuse carbon dioxide (CO2) with carbon monoxide (CO) monitoring. They are both two different gases that require each their unique gas detectors.


This article was written by me, Dr. Koz (no ghostwriters and no AI content here!). I am the President of Forensics Detectors (CA, USA). I am also a subject matter expert on gas sensor technology, gas detectors, gas meters, and gas analyzers. I have been designing, building, manufacturing, and testing toxic gas detection systems for over 20 years.... and still love it.

Email:  drkoz@carbondioxidedetector.com

dr Koz
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