Say hello to the AQS1 compact air quality monitor!

Say hello to the AQS1 compact air quality monitor!

Article Details

Last Updated

18 November 2021


02 February 2017



Introducing the AQS1

We are pleased to announce a new arrival in our ambient air monitoring product line up – the AQS 1 compact air quality station. Our factory is now accepting advance orders for delivery in March 2017.

The AQS 1 combines the proven particle measurement technology from Aeroqual’s AQM 65 and Dust Sentry products (1000s of units sold) with our world-beating sensor-based gas analyser modules from the AQM 65.

The initial release combines the particle monitor and ozone (O3) sensor-based analyser module from the AQM 65 in a more compact Dust Sentry-sized enclosure. PM2.5 and O3 make a logical combination. They are important background pollutants. Air quality agencies in many parts of the world are getting to grips with PM2.5, but for many ozone formation and distribution remains poorly understood.

What is it?

The AQS 1 combines a nephelometer, PM2.5 sharp cut cyclone, and Aeroqual’s industry leading GSS (gas sensitive semiconductor) ozone sensor technology. Housed in a rugged, lockable weatherproof enclosure, the monitor is lightweight (less than 13kg) and can be installed and moved with ease.

The AQS 1 can be configured to measure PM2.5 and ozone simultaneously, or PM2.5 only, or ozone only. It can also be configured to measure other particle fractions e.g. TSP, PM10, and PM1. Because it is modular you may order the unit with just PM2.5 for example and add ozone at a later date (without returning to the factory).

Numerous field tests have shown our GSS ozone sensor correlates very closely with US EPA / EU reference equivalent instruments. It has excellent sensitivity (down to 1 part-per-billion) and is not cross sensitive to other pollutants such as nitrogen dioxide, which is a common issue with other O3 sensors. The sensor is minimally affected by changes in temperature and humidity. That allows the AQS 1 package to deliver similar Near Reference data quality as the AQM 65 (see field test results below).

The AQS 1 is a fully integrated monitor. It includes an industrial PC which runs an embedded software system for remote technical support, data management and analytics. The PC has storage for more than 5 years of data, and it includes WIFI and Ethernet connectivity as standard features. Data transmission over cellular network is possible with the inclusion of an optional modem.

Like all Aeroqual’s ambient air monitoring stations the AQS 1 runs Aeroqual Connect our instrument operating system and can be used with Aeroqual Cloud, our cloud-base data acquisition system. Connect and Cloud allow for advanced data analysis and remote technical support.

Why did we make it?

Lots of our Dust Sentry customers have expressed interest in measuring gases alongside particulate matter. The AQM 65 compact air monitoring station is one option. But some customers don’t need to measure multiple gases (the AQM 65 can measure up to eight) – they just want to measure one or two. The AQS 1 is therefore an instrument for those seeking to answer targeted air quality questions.

For example at a mining site measuring PM10, they might also want to know how much nitrogen dioxide or sulphur dioxide their workers are being exposed to. Or a customer measuring PM2.5 in a wide area network might want to know how ozone levels map across their airshed. A consultant monitoring volatile organic compounds from a remediation site might also want to know how much dust the activity is creating. In time the AQS 1 will be able to provide a solution in all these cases.

We also have customers who want to use our amazing GSS ozone sensor for distributed outdoor air quality surveys. In the past we have directed them to our portable ozone monitor, and some customers have achieved incredible results. Unlike our portable monitors however, the AQS 1 is designed for long term fixed monitoring. It is fully weather proof, has in built data and communications, and can be calibrated in the field.

That’s how the need for the AQS 1 arose – customers with specific gas and particulate monitoring needs who don’t need something as big as the AQM 65 air monitoring station.

How is it different to the AQM 65?

The key differences between the AQS 1 and the AQM 65 are set out in the table below:

AQM 65

  • Measures up to six gases and four particulate fractions simultaneously

  • Fully temperature controlled enclosure, rated for -35°C to +50°C

  • Integrated remote field calibration system optional


  • Measures one gas and one particulate fraction simultaneously

  • No temperature control – rated for -10°C to +45°C

  • Can be field calibrated by portable calibration equipment

How does the AQS1 perform?

In field tests the main thing we wanted to check was the effect of temperature on the ozone sensor. Having run thousands of Dust Sentries in the field, we knew that the particle monitor technology performed well in a non-temperature controlled environment. We had some field experience with our portable ozone monitors and lab tests show that the ozone sensor is stable in various temperature conditions, but we wanted to check temperature and/or humidity effects in real world conditions.

Field tests were run over several months in China and the US during high summer. The results are covered in the following reports – China and USA.

Focusing on the China test results, data capture rates were above 96%.  The results show excellent correlation with independently run EPA-approved reference methods. The 1-hour average O3 concentrations measured by the AQS 1 showed excellent correlation with the reference O3 analyzer with an r² = 0.97. The 24-hour average PM2.5 concentrations measured by the AQS 1 also showed a good correlation to the reference PM2.5 instrument with an r² = 0.78.

The AQS 1 was exposed to ambient temperatures that ranged from 18.8 to 34.1 °C and relative humidity that ranged from 31.3 to 100 %. During this period, the internal temperature of the AQS 1 was approximately 12 °C higher than ambient which was expected and well within design parameters. No significant temperature or relative humidity interference effects were observed on either the AQS 1 O3 or PM2.5 measurements.


What's next?

The AQS 1 is being introduced to our global distributor network and advanced orders are now being accepted for delivery from March 2017. This is for the initial ozone/PM combination (or ozone only).

Over the coming months Aeroqual is working on other gas modules that will be tested in the AQS 1. Currently the most in-demand gas modules are NO2 and VOC in that order. If you have a specific gas of interest, we’d love to hear from you.

The AQS 1 is the first product from a larger R&D programme that aims to achieve Near Reference levels of data quality whilst reducing the size and cost of the instrument. A critical challenge in the programme is how to deal with temperature and humidity effects on the sensors in a way that doesn’t compromise data quality or traceability. The AQS 1 shows that we are well on our way.

Further prototypes are under development and we look forward to sharing them with you as they become available.

What one?

Learn more about the AQS 1 on the following product pages:

To inquire about the AQS 1 please contact us. We’ll answer your questions directly or introduce you to one of our many qualified service partners around the world.

Thanks for your interest and attention!

Learn more about the AQS1

Get in touch to discuss how the AQS1 can help on your next air monitoring project.