Best Carbon Monoxide Detection Apps

250+ iOS apps curated and reviewed

4.3 avg rating

20 free apps

Updated October 2026

OTG CO Leak Detector is the household name in carbon monoxide detection, but it's far from the only option. We track 250+ alternatives and competitors on iOS — many free, many higher-rated than you'd expect.

Compare top Carbon Monoxide Detection Apps (October 2026)

#	App	Price	Rating	Ads	In-App Purchases	Updated
1	OTG CO Leak Detector	Free	—	No	No	May 2026
2	CO2 sensor	Free	3.4★ (7)	No	No	Oct 2026
3	Tracer - Gas Detector	Free	5.0★ (1)	No	No	Sep 2026
4	My AQI Air Quality & Pollution	Free	4.6★ (2.6K)	Yes	Yes	Oct 2026
5	Detector CO2	Free	2.0★ (1)	No	No	May 2026
6	Carbostar Sense	Free	—	No	No	Jun 2026
7	EMF Detector - Ghost Hunting	Free	—	No	No	Jul 2026
8	CO2 Monitor 2	Free	—	No	No	May 2026

Top Picks for Carbon Monoxide Detection

#1

OTG CO Leak Detector by Baby Alert International Inc

Indoor Air Safety

Editor's Choice

0.0(0 ratings)

Free

OTG CO Leak Detector screenshot 1

OTG CO Leak Detector screenshot 2

OTG CO Leak Detector screenshot 3

OTG CO Leak Detector screenshot 4

OTG CO Leak Detector screenshot 5

#2

CO2 sensor by sighmon

Display SCD-41 CO2 readings.

Strong Contender

3.4(7 ratings)

Free

CO2 sensor screenshot 1

CO2 sensor screenshot 2

CO2 sensor screenshot 3

CO2 sensor screenshot 4

CO2 sensor screenshot 5

CO2 sensor screenshot 6

Monitor CO2, temperature, and humidity levels in real-time using a Bluetooth sensor. Save readings with location data and sync them across Apple devices via iCloud. View historical data on a map.

#3

Tracer - Gas Detector by ReFleX Wireless Inc.

for various gas leak detection

Worth Considering

5.0(1 ratings)

Free

Tracer - Gas Detector screenshot 1

Tracer - Gas Detector screenshot 2

Tracer - Gas Detector screenshot 3

Tracer - Gas Detector screenshot 4

This app works with a smartphone-powered USB device to detect various gas leaks like methane and formaldehyde. It provides real-time monitoring and alerts to enhance safety at home or work. Pinpoint emission sources effortlessly for peace of mind.

More Carbon Monoxide Detection apps to explore

My AQI Air Quality & Pollution

My AQI Air Quality & Pollution

My AQI Air Quality & Pollution

Live PM2.5, Smog Map & Widget

Check real-time air quality and pollution levels for your current location or any city worldwide. Understand the concentration of various pollutants and receive alerts for unhealthy conditions. Find protection equipment and manage respiratory health.

Real-time AQI and pollutant concentrationSearch and save global locationsWildfire and smog monitoring

free with in-app purchases

by Geotap Games S.L.

Measure ambient CO2 levels using a compatible device. This utility app provides environmental data for your surroundings.

Measure CO2 levelsUtilizes device capabilitiesEnvironmental data display

Carbostar Sense

Carbostar Sense

Carbostar Sense

Smart CO₂ Air Monitor

EMF Detector - Ghost Hunting

EMF Detector - Ghost Hunting

EMF Detector - Ghost Hunting

Detect Paranormal Activity

by Life-Gard Marine

SPARROW - CO & Air Quality

SPARROW - CO & Air Quality

SPARROW - CO & Air Quality

This app works with a portable carbon monoxide monitor to provide real-time air quality data and safety alerts. It displays CO levels, tracks exposure over time, and can send emergency text alerts to a designated contact.

Real-time CO level displayCustomizable warning levelsExposure tracking and graphing

💪 Health & Fitness

Metal Detector and EMF Scanner

Metal Detector and EMF Scanner

Metal Detector and EMF Scanner

Scan Metal, Coins & Objects

Transform your phone into a versatile detection tool. Identify metals, coins, stones, and measure electromagnetic fields using your device's sensors and AI. Explore your surroundings and discover hidden objects with real-time scanning and smart recognition.

Metal detectionEMF scanningLive camera object detection

free with in-app purchases

by CHEERSAIL TECHNOLOGY SHARES CO., LIMITED

Stud Finder: Metal Detector

Stud Finder: Metal Detector

Stud Finder: Metal Detector

Wall Scanner for Pipes & Wires

Transform your iPhone into a precise wall scanner. Easily locate studs, pipes, wires, and other hidden metal objects for DIY projects and home improvements. Offers multiple detection modes and adjustable sensitivity for accurate results.

All-in-one wall scannerDetects studs, pipes, wires, and more4 distinct detection modes

ecobee by Generac

ecobee by Generac

ecobee by Generac

Comfort, security, resilience.

Control your smart home devices, including thermostats, cameras, and sensors. Automate your home for comfort and peace of mind, and monitor entryways and cabinets with intelligent alerts. Save energy with custom schedules and find potential rebates.

Control SmartThermostat, SmartCamera, and SmartSensorStep-by-step installation guidesCustomizable thermostat schedules

free with in-app purchases

Your link to safety.

This app connects to smart home safety devices, providing real-time alerts for smoke, CO, air quality, and water leaks. It offers features like Smart Hush, remote notifications to loved ones, and advanced indoor air quality monitoring through a subscription service.

Real-time alarm notificationsSmart Hush functionalityQR code setup for Wi-Fi connection

by Air Advice For Homes Inc

BLE Gas Sensor Monitor

GasVigil User App

FAQ about Carbon Monoxide Detection

Are there free carbon monoxide detection apps for iPhone?

Yes — 20 of the top carbon monoxide detection apps we rank are free to download, including OTG CO Leak Detector and CO2 sensor.

Does OTG CO Leak Detector have ads or in-app purchases?

OTG CO Leak Detector has no ads and has no in-app purchases, according to its App Store listing as of October 2026.

How many carbon monoxide detection apps are on the App Store?

We track 250+ carbon monoxide detection apps on the iOS App Store as of October 2026, ranked by rating, recency, and analysis of real user reviews.

Related searches

free carbon monoxide detector carbon monoxide detector