# BelAir vs GUS

The clearest difference is update cadence: BelAir at every 2 months against GUS's every 8 months. BelAir also leads on iOS requirement (13.0 vs 15.0). On price, ads, in-app purchases and device support there is nothing between them.

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

BelAir ships an update every 2 months, GUS every 8 months. The most recent releases landed on October 20, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | BelAir | GUS |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 12.2% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 2 months** | Every 8 months |
| Monetization | Free | — |
| Size | 60 MB | 15 MB |
| Requires iOS | **13.0** | 15.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Belgian Interregional Environment Agency (IRCEL - CELINE)](https://appshunter.io/developer/1040177412) | [Trainin](https://appshunter.io/developer/1732652497) |

## What reviewers say

### BelAir

[App page](https://appshunter.io/ios/app/belair/id1441924418)

Provides real-time and forecasted air quality scores across Belgium. It uses a comprehensive index based on various pollutants and offers insights into long-term air quality trends and health impacts.

**Highlights:** Real-time air quality scores, Air quality forecasts, Long-term air quality evolution, BelAQI index explanation, Pollutant concentration data, Health impact insights

**Features:** macOS Compatibility

**In-app purchases:** none


### GUS

[App page](https://appshunter.io/ios/app/gus/id6745213156)

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

**In-app purchases:** none


## Frequently asked questions

### Is BelAir free?

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

### Is GUS free?

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

### Do BelAir or GUS have ads?

Neither BelAir nor GUS shows ads.

### Which is updated more often, BelAir or GUS?

BelAir ships an update every 2 months, and GUS every 8 months. Most recently, BelAir was updated on October 20, 2026 and GUS on October 28, 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.*