# Airthings vs Smell Annotator

The clearest difference is rating: Airthings at 4.4 against Smell Annotator's 1.0. Airthings also leads on ratings volume (3K vs 1). Smell Annotator's advantage is monetization model (free vs free with in-app purchases) and iOS requirement (15.0 vs 17.6). On price, update cadence, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Airthings holds the better App Store score, 4.4 against 1.0. That said, the two scores are not equally well evidenced: Airthings has 3K ratings behind it against 1, so its average is the more settled of the two.

Airthings ships an update fortnightly, Smell Annotator monthly. The most recent releases landed on September 22, 2026 and September 14, 2026 respectively.

## The numbers

| Metric | Airthings | Smell Annotator |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.4 (3K ratings)](https://appshunter.io/ios/app/airthings/id1560329275/reviews)** | [1.0 (1 ratings)](https://appshunter.io/ios/app/smell-annotator/id1607528175/reviews) |
| Number of ratings | **3K** | 1 |
| Positive reviews | 33.3% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Fortnightly** | Monthly |
| Monetization | Free with in-app purchases | **Free** |
| Size | 102 MB | 53 MB |
| Requires iOS | 17.6 | **15.0** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Airthings ASA](https://appshunter.io/developer/1101077902) | [SmartNanotubes Technologies](https://appshunter.io/developer/1607528177) |

## What reviewers say

### Airthings

[App page](https://appshunter.io/ios/app/airthings/id1560329275)

Monitor and improve your indoor air quality with smart devices. Get real-time insights, track trends, and receive actionable advice to enhance focus, reduce allergies, and sleep better. Control your air purifier and stay informed about pollen forecasts.

**Highlights:** Quick device setup, At-a-glance air quality indicators, Detailed trend tracking, Air purifier remote control, 5-day pollen forecast, Air quality notifications, Personalized air reports

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none

**What reviewers like**

- 🚀 Simple to understand and setup
- 🚀 Intuitive and easy to use app
- 🚀 Efficient and fast
- 🚀 Provides great information on air quality
- 🚀 Accurate and reliable sensor readings

**What reviewers complain about**

- 🐛 App has connectivity issues, often fails to sync
- 🐛 App is buggy and has many errors
- 🐛 Inaccurate or inconsistent sensor readings
- 🐛 Difficult to set up and connect devices
- 🐛 Lack of customization options for thresholds and notifications

**Reported bugs**

- App crashes frequently
- Unable to add new devices or accounts
- Incorrect color coding and data display
- Delayed or missing sensor data updates
- Bluetooth connectivity issues

**Requested features**

- Add HomeKit integration
- Allow custom thresholds and notifications
- Improve data visualization and historical trending
- Add more detailed information on air quality issues and remedies
- Provide an iPad-optimized version of the app


### Smell Annotator

[App page](https://appshunter.io/ios/app/smell-annotator/id1607528175)

This application enables machines to digitally sense and analyze smells using nanomaterial-based technology. It allows users to view, annotate, and recognize smell measurements in real-time, functioning as part of a developer kit.

**Highlights:** Smell recognition, Smell digitalization and annotation, Saving and loading measurements, Real-time measurement visualization, Offline data collection, Graph synchronization

**Features:** Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Airthings free?

Airthings is free to download, with no in-app purchases.

### Is Smell Annotator free?

Smell Annotator is free to download, with no in-app purchases.

### Which has better reviews, Airthings or Smell Annotator?

Airthings is rated higher. Airthings averages 4.4 out of 5 from 3K ratings, while Smell Annotator averages 1.0 from 1 ratings.

### Do Airthings or Smell Annotator have ads?

Neither Airthings nor Smell Annotator shows ads.

### Which is updated more often, Airthings or Smell Annotator?

Airthings ships an update fortnightly, and Smell Annotator monthly. Most recently, Airthings was updated on September 22, 2026 and Smell Annotator on September 14, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*