# Hazel - 1-hour PM2.5 PSI Readings for Singapore

> Real-time 1-hour PSI readings for Singapore haze. (iPhone/iPad app by Clean Shaven Apps.)

- Source: https://appshunter.io/ios/app/hazel-1-hour-pm25-psi-readings-for-singapore/id1047060107 (this page in markdown: same URL + `.md`)
- Developer: [Clean Shaven Apps](https://appshunter.io/developer/599220569)
- Category: Weather
- Price: Free
- Rating: 5.00/5 from 1 App Store ratings
- Age rating: 4+
- Requires: iOS 8.0 · 19 MB
- Languages: American English
- Released: 2015-10-25
- Data updated: 2026-08-12
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/hazel-1-hour-pm25-psi-readings-for-singapore/id1047060107/reviews.md

## What is Hazel?

Hazel tells you how bad the haze is right now, right where you are.

Make better decisions about whether you need a mask, or if you should be bringing your baby out.



Hazel calculates the 1-hour PSI using a formula provided by NEA. It converts the concentration of PM2.5 pollutant into a scale from 0–500.

Hourly push notifications keeps you up to date about the latest 1-hour PSI readings the moment NEA releases the data.

## Key features

- 1-hour PSI readings
- PM2.5 concentration conversion
- NEA formula implementation
- Hourly push notifications
- Haze level assessment


## Frequently asked questions about Hazel

### What is Hazel's current PSI reading?

Hazel provides real-time 1-hour PSI readings for Singapore, calculated using the NEA's formula for PM2.5 concentration. The app displays this on a scale from 0-500 to indicate haze severity.

### How does Hazel calculate PSI?

Hazel utilizes a formula provided by the NEA to convert the concentration of PM2.5 pollutants into a PSI (Pollutant Standards Index) scale ranging from 0 to 500.

### Does Hazel offer updates on haze levels?

Yes, Hazel sends hourly push notifications to keep users informed about the latest 1-hour PSI readings as soon as NEA releases the data.

### Is Hazel available on Android devices?

Hazel is currently supported on iPhone and iPad devices. It is not available for Android at this time.

### What is the age rating for Hazel?

Hazel has an age rating of 4+, making it suitable for a wide range of users concerned about air quality.

### How often is Hazel updated?

Hazel was last updated on October 25, 2015, with version 1.0. Further update frequency is not specified.

### What do users like about Hazel?

Based on its rating of 5.0 stars from 1 rating, users likely appreciate its direct and timely information regarding Singapore's haze conditions.

### Does Hazel have ads?

No, Hazel is an ad-free application. Users can access all its features without encountering advertisements.

## Version history (last 1 release)

### 1.0 — 2015-10-25

This app has been updated by Apple to display the Apple Watch app icon.

## Apps similar to Hazel

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [ASEAN Air](https://appshunter.io/ios/app/asean-air/id6502939879) | — | Free | Weather |
| [Pollen, Air Quality-Airlytica](https://appshunter.io/ios/app/pollen-air-quality-airlytica/id6756318761) | — | Free | Weather |
| [Haze@SG](https://appshunter.io/ios/app/hazesg/id663816616) | 5.0 (2) | Free | Weather |
| [SG Air](https://appshunter.io/ios/app/sg-air/id881004442) | 3.0 (2) | Free | Weather |
| [DewPtFm](https://appshunter.io/ios/app/dewptfm/id6504697113) | — | Free | Weather |
| [Perfect Air](https://appshunter.io/ios/app/perfect-air/id6448851304) | — | Free | Weather |

## More apps by Clean Shaven Apps

- [Elk Currency Converter](https://appshunter.io/ios/app/elk-currency-converter/id1189748820)

All apps by Clean Shaven Apps: https://appshunter.io/developer/599220569

## Related topics

[haze explore](https://appshunter.io/ios/topics/haze-explore) · [pm2.5](https://appshunter.io/ios/topics/pm2-5)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-12.*