News Blog

Superior service and expertise help ET retain prestigious Greater Manchester contract.

PR5 Enclosure

Stroud based air quality monitoring equipment and service contract provider, Enviro Technology Services (ET), are both proud and delighted to have retained the Greater Manchester Air Quality Network (GMAQN) yet again, following on from a recent tender exercise.

The GMAQN currently comprises of 20 real-time monitoring stations on what is, one of the largest regional metropolitan networks in England. The monitoring stations, located in Wigan, Trafford, Tameside, Stockport, Salford, Rochdale, Oldham, Manchester, Bury and Bolton are all professionally serviced, maintained, and supported by ET.

The unification and harmonisation of the AQM stations operated by the various Greater Manchester local authorities began in 2013 with the birth of the GMAQN, and ET is proud to have been involved with this network since its inception.

ET has a proven track record over the years, providing the network with excellent all-round service and support and consistently high data capture rates.

ET’s Managing Director, Duncan Mounsor concludes “we are extremely proud to continue our association with the GMAQN and our retention of this contract truly does reflect our commitment to quality and focus on superior customer service. I’m also as ever, thankful to our customer support admin team and of course our team of service engineers, especially our regionally based engineers in the Greater Manchester and surrounding areas”.

PR5 Enclosure with 2 x BAMs and 1 NOx Manchester

Where’s My Data?

Data grapgh

Somewhere, in an innocuous looking, typically green, roadside enclosure near you, instruments will be humming away, sucking in ambient air, analysing it and recording data - day and night, week after week, year after year. But nobody is interested in that, are they? Just as long as the data keeps flowing.

Meanwhile, miles away in an office somewhere and with coffee in hand, you or your data manager, sit in front of a computer screen, browse to a website and review a graph or numbers in a table – or maybe instead of a website, a few additional keystrokes result in those hidden instruments being interrogated remotely. Either way, your air quality data appears onscreen and its looking good. You smile and move on to your next task of the day.

Combined Graph fro CS blog

But what will you do if one day, like a tap running dry, your vital data suddenly stops streaming in? Who would be the first to notice? You? Your community? Local activists? What would they have to say if the outage wasn’t resolved immediately? Suppose it happened during a high pollution incident - in a location of significant community interest? Would they think you’re hiding something? How difficult could they make things for you?

The instrumentation supplying your air quality data is very likely, right at the back of your mind. As long as the data streams in reliably and continuously, there’s no reason to give them any consideration, is there? But when the tap turns off, the screen goes blank and the phone starts ringing, where do you turn?

ET sees air quality monitoring from a different perspective. We understand that when you buy air quality monitoring instruments or a service and maintenance contract from us, you’re actually buying data and peace of mind. This is why we only supply the best, most reliable and independently certified instruments; fully supported by a regionally-based team of factory-trained service engineers with over 250 years of collective experience.

We know that if you get the basics right, your data will be too. So, if you’ve invested in proven, certified, monitoring equipment, your defensible data will not only keep flowing but if the worst should happen and the data tap turns off, your service and maintenance contract with ET means that you simply pick up the phone or drop us an email and an ET expert will be there to turn it on again.

ET supports Cheltenham and Gloucester Hospital Charity following massive strain on NHS services in 2020 & 2021

Cheltenham and Gloucester Hospitals charity logo

Ever since ET’s CSR committee was set up, following an inspiring CSR day held by one of our forward thinking suppliers some years ago, we have been committed to supporting environmental and conservation charities. Including: The Woodland Trust, The Bumblebee Conservation Trust, Cotswold Canal Trust and South West Ambulance Service.

Charity logo's

Now, following the massive strain on the NHS throughout 2020 – 2021, we feel it’s fitting to support an NHS charity this time round. And now, after making an initial donation to Cheltenham and Gloucester hospitals charity in June, we are busy planning some fundraising ideas so that we can continue support this worthy cause.

When they’re not coming up with fundraising initiatives, ET’s CSR committee look for ways to lower ET’s impact on the environment and seek out ways to make a positive difference in the places ET operate, and in the lives of our employees.

Below are a few of the recent CSR initiatives ET and it's employees have been involved in.

Ecobrick CSR
Crisp packet CSR initiative
Travel CSR initiative
Mental Health CSR initiative
Cancer care CSR initiative


The Smogmobile analyses data and builds awareness at Gloucestershire school & in Westminster for Clean Air Day 2021

Upton st leonard school

As many businesses and environment bodies around the UK prepared for Clean Air Day 2021, ET’s zero emissions air quality laboratory - the Smogmobile, was no exception. 

After a thorough check over of all it’s highly sensitive analysers, the Smogmobile took to the road ahead of June 17th to do some preparatory analysis of air quality at Upton St Leonard Primary School in Gloucestershire, at morning drop off. Pupils were asked to walk, cycle or scoot to school so a comparison study could be performed a week later on CAD 2021.

Upton St Leonards tweet on CAD 2021

During the school's assembly ET’s MD, Duncan Mounsor, gave a virtual presentation about the dangers of air pollution and the small actions we can all take to reduce it. On CAD itself, a truck with an idling engine delivering to the school showed up as a huge spike in emissions, illustrating how there’s no place for idling engines, especially near schools!

CAD graph at Upton St Leonard school June 2021

Two days ahead of CAD Duncan took the Smogmobile down to Westminster to measure modern urban pollutants including NO2 and PM10 & PM2.5. The study was commissioned by Westminster City Council in conjunction with The Northbank BID as part of their ‘Air Quality Action Day’ initiative. Initially monitoring at The Strand and later at Regents St, it was able to provide real time measurements of nitrogen dioxide emissions, particulates and black carbon to highlight the risks created by pollution from vehicles and engine idling.

Westminster City Council are working hard to improve air quality and reduce carbon emissions through their diesel surcharge scheme and #Don’tbeidle campaign. 

Westminster CAD photo

ET received a lovely email of thanks the following day...

Westminster Testimonial 3
ET take pride in helping these kind of initiatives raise community awareness. 

Luckily with the Smogmobile we have the perfect tools to do just that!

ET have already taken a number of booking enquiries for the Smogmobile for Clean Air Day 2022.

You can see Duncan Mounsor talk about how the Smogmobile monitored pollution for Westminster City Council and The Northbank BID in the video below.

DMN on Westminster vid

For more information on the Smogmobile, check out our brochure.

Easy smartphone connection now available with Graywolf Smart IAQ and Toxic Gas Probes

GrayWolf smartphone capability

With indoor air quality being more topical than ever, ET are pleased to announce that our long-standing supplier for indoor air quality monitoring products, GrayWolf Sensing Solutions, have performed upgrades to the GrayWolf DirectSense® II probes so they now connect via Bluetooth LE wireless to Apple and Android devices.

The highly reliable, adaptable DSII probes for indoor air quality (IAQ) and toxic gas testing/monitoring have Apps for iOS and Android operating systems available (free) on the Apple and Google App stores.

You can now use your smartphone or tablet as a multi-parameter display, data-logger and far more.

Choose from over 25 highly accurate, smart indoor air quality, green building, industrial hygiene, and HVAC sensors including TVOCs (PID), Carbon Dioxide (NDIR), Ozone (electrochemical), CO, NO2, NH3, SO2, NO, Cl2, H2S, HCN, HCl, O2, H2, %RH, °C/°F and many others.

Each probe accommodates from two, up to eight, true plug-and-play sensors into a single handheld, desktop, or wall-mounted housing. Proven sensors offer low limits of detection and exceptional accuracy.

School IAQ Interior Probe Monitor FNL

Store “snapshot” logs during walk-throughs or set up logging over time at the interval of your choice on the smartphone. Display up to eight real-time readings simultaneously or show trend graphs on your screen.

Feature-rich, the smartphones can add photos, videos, text, audio notes and more directly to data files for efficient, reliable documentation. On-board educational info will be added soon, such as help videos, sensor, and feature tips. Easily e-mail logged data, with all notes attached, and utilise GrayWolf’s WolfSense® PC software for download, graphing and analysis, or optional Advanced Report Generator for automated, detailed reports and custom report template creation.

Where other manufacturers have prioritised convenience over performance, GrayWolf’s extensive development effort was put into assuring that the sensor smartboards would not introduce noise or degrade accuracy, stability, or limits of detection (LODs) for the convenience of end-user swappable sensors.

The full range of GrayWolf’s indoor air quality products can be purchased in the UK and Ireland from Enviro Technology Services.

View our Indoor Air Quality products here.

View the GrayWolf DirectSense Brochure here.

Spotlight on ET supplier – Digitel Elektronik AG

Digitel employees

Digitel AG is a world-renowned manufacturer of specialist, high-quality, automatic air samplers for both high and low volume air monitoring applications. Meeting the technical performance and quality assurance requirements for use on regulatory networks worldwide, Digitel samplers are also suitable for PM2.5 and PM10 measurements according to EN12341:2014. 

As one might expect from a precision Swiss manufacturer, Digitel instruments are supremely well engineered and have a reputation for quality, high reliability and long life in the field.

Digitel Fact File

  • Digitel is a family business, started in 1970 by Dölf Muther
  • It employs 17 people in Switzerland and 2 in Austria
  • Digitel’s main office is in Volketswil, Switzerland (in the greater Zurich area)

LEA 1122 2
LEA 0966 2
Swiss flag copy
Located in the heart of Europe, Zurich is one of the most important economic, cultural, and social centres of Switzerland. Situated on the shore of Lake Zurich, with the Alps on the horizon, the city is both historic and diverse, and the surrounding areas provide numerous exciting and relaxing recreation areas for locals and visitors alike.


The two most popular Digitel samplers sold by Enviro Technology in the UK and Ireland are the DHA-80 High Volume and DPA-14 Low Volume samplers. These types of samplers are used on several of the UK’s Defra national regulatory networks as well as at several university ‘super-sites’ including, Manchester, Birmingham and London.

DIGITEL Aerosol Sampler DHA-80
High volume sampler (HVS) for autonomous, continuous measurements.
Digitel HVS DHA 80

  • Flow rate: 420 – 600 l/min.
  • Optional flow rate: 100 – 1000 l/min.
  • Accuracy of measured flow rate: <+/- 2%
  • Suction blower average lifespan: 36,000 hours
  • Number of filters: 15, automatically changed on pre-programmed basis
  • Filter size: 150 mm diameter
  • Built within IP54 rated external field housing OR 19” rack mounted
  • Optional compressor for cooled sample storage
  • USB, RS232, Ethernet, RS485, GSM module (option)
  • PM10, PM2.5, PM1.0, TSP inlet heads available
  • PAH cartridges (single or 4 cartridge automatic)
  • Many other options – widely configurable
  • For PM2.5 and PM10 measurements according to EN12341

DIGITEL Aerosol Sampler DPA-14
Low volume sampler (LVS) for autonomous, continuous measurements.
Low Volume Sampler1 DPA 14

  • Automatic filter changer for 24 filters
  • Filter diameter 47 mm
  • Constant and precise flow: 5 – 50 l/min
  • Volume flow control accuracy: <2%
  • Mean life of suction unit >16,000 hours
  • Built within IP54 rated external field housing
  • Ambient temperature and pressure sensor
  • TSP, PM10, PM2.5 and PM1.0 inlets available
  • For PM2.5 and PM10 measurements according to EN12341:2014
  • Wide range of options and accessories
  • Fully programmable touchscreen operation
  • Optional compressor for cooled sample storage
  • USB, RS232, Ethernet, RS485, GSM module (option)

Click here for further details on the Digitel DHA-80

Click here for further details on the Digitel DHA-14

And for more information the DHA-80, DPA-14 and all other Digitel products visit:

Enviro Technology Services (ET) signs with Nikira Labs to offer Open-Path Extinction Analysers (OEAs) – the next generation instruments for visibility and aerosol studies.


ET, the UK’s leading supplier of environmental monitoring technology has teamed up with Silicon Valley based Nikira Labs to offer next-generation, highly portable optical extinction analysers for a wide range of visibility and aerosol monitoring applications.

The OEA-532 measures optical extinction and visibility in air with unprecedented accuracy, it combines open-path cavity ringdown measurements with a patented self-referencing system resulting in high precision, minimal sample handling and little or no drift.

Weighing in at only 7.7 kg and measuring just 49 cm x 33 cm x 18 cm, it is built into a rugged, water-resistant Pelican case, making it highly portable and supremely versatile.

And with low power consumption of just 35 Watts, the OEA-532 can run on battery power for extended periods in the field where mains power may not always be available. The instrument features onboard data storage for more than 2-years of continuous data and data can be accessed via USB or remotely via a cellular modem.

The single wavelength (532 nm) OEA-532 is available in two formats, 1-Hz (standard) or the super-fast 10-Hz version for Eddy Covariance applications (model OEA-532EC).

Applications are many and include airports, highways, tunnels, military, air quality, air pollution, aerosol research, national parks, forest areas, volcanic areas, clean rooms and semiconductor fab and research.

ET’s Managing Director Duncan Mounsor, and Nikira Labs CEO Rupal Gupta are both excited about this positive collaboration, and Duncan concludes by saying “ET is all about brining innovative technology to market, and the advanced and compact Nikira Labs OEA-532 fits perfectly into our portfolio of instruments aimed primarily at aerosol researchers and earth/environmental scientists. There is also crossover into other sectors such as airports and highways, and ET is well placed to serve all of these areas”.

ET’s agreement with Nikira Labs is for sales in the UK and Ireland as well as other selected territories.

For further information contact the ET Sales team today on +44 1 (0)1453 733200 or email

Optical Extinction Analyser (OEA-532) (

ET gears up for Clean Air Day!

Our favourite time of year has come around again. The suns shining (at last) and Clean Air Day is just around
the corner (June 17th).

After a year of lockdowns and a drastic reduction in traffic, Clean Air Day is timely this year. As covid measures lift and traffic ramps up again what better time to support UK’s largest air pollution campaign, Clean Air Day.

As in previous years, our zero-emission mobile air quality monitoring laboratory, the Smogmobile, will be out and about measuring pollutants and raising awareness. This year’s CAD theme is protect our children’s health from air pollution so we felt there was no better way to support this than monitoring pollutants at a local school.

CAD 2021 themed social image

ET’s MD, Duncan Mounsor will be taking smoggy to Upton St Leonards primary the week before Clean Air Day to check up on local levels of NOx and PM2.5 at drop off. He’s going to stick around for a bit so the children can come and have a look at his highly sensitive precision analysers collecting data. Later in the day Duncan will connect virtually with the school to educate the children about where air pollution comes from and what we can do about it.

The school are whole heartedly behind the plan and are very active in encouraging the pupils to think about the environment and are committed to promoting Clean Air Day both internally and externally. Pupils who travel greener on the 17th June will be awarded house points.

The Smogmobile has proved successful at monitoring pollutants at schools previously. In this case study gloucestershire-county-council-school-study.pdf ( you can read how Gloucestershire County Council commissioned the Smogmobile to monitor at 7 schools to determine the spatial distribution of air pollutants (particularly nitrogen dioxide, PM10, and ozone) to compare levels during half term and term time.

On June 17th The Smogmobile will be out again taking measurements around ET’s hometown of Stroud, Gloucestershire where it will be on patrol to give a second-by-second picture of common pollutant levels and identifying localised air pollution hot spots.

Look out for Clean Air Day updates and photos on our social media channels.

For more information on how the Smogmobile can help you monitor pollutants, contact ET today.    01453 733200

Ammonia – a toxic modern day pollutant

Ammonia infographic

As one of the most toxic modern-day pollutants, Ammonia emissions are an increasingly active area of research.

The UK has national emission reduction commitments for overall UK emissions of five damaging air pollutants, one of these is ammonia. (DEFRA Clean Air Strategy 2019)

Having experienced a fall in ammonia emissions from 1990’s up until 2013, the UK then saw a reverse in trend and now there’s a significant increase in levels ( Quality: explaining air pollution – at a glance).

Ammonia graphic

There are two main causes for concern:

1. its contribution to the formation of secondary fine particulate matter (PM) including PM2.5, one of the most dangerous modern-day air pollutants with far-reaching human health impacts.

2. ammonium deposition which causes significant long-term damage to sensitive habitats and ecosystems as well as eutrophication, the over-nutrification and excess nitrogen in aquatic environments leading to acidification and a reduction in species richness and biodiversity.

As part of our growing knowledge bank of gas and particulate factsheets, ET have produced a factsheet, one in a series, that explains what ammonia is, why it’s so important to measure and the challenges faced by those in pollution control.

You can read our ammonia factsheet here.

Los Gatos Research

Traditionally ammonia has been difficult to measure in trace concentrations in ambient air (i.e. at ppb levels) due to the extremely reactive nature of the gas. ET’s ABB-Los Gatos Research’s range of monitoring solutions for the measurement of ammonia provide a highly precise measurement with a low sensitivity to interference. These are popular with field and lab-based researchers alike. Available in rack-mounted and ultraportable form, they can suit your exact requirements.

• Ultraportable Economical Ammonia Analyser (17kg, built into Pelican case)

• Rackmount Economical Ammonia Analyser (19” rack mount, standard configuration)

• Enhanced-Performance Rackmount Economical Ammonia Analyser (19” rack mount with temperature regulation for improved precision and drift)

• Trace Ammonia Analyser (19” rack mount, Quantum Cascade Laser for highly-sensitive measurements in the mid-infrared, liquid nitrogen cooled detector, temperature regulation)

We also offer robust ammonia measurements using photo acoustics and quantum cascade laser allowing for continuous monitoring with a detection limit of 1ppb with our range of LSE NH3 monitors

LSE monitors .

• NH3 1700 rack-mounted, photoacoustic, 2ppb precision

• NH3 1710 rack-mounted, photoacoustic, 25ppb precision

You can find these and our full range of air quality monitors at

To speak to a specialist, contact ET today.     01453 733200

Opsis DOAS for the measurement of air pollutants

Kevin Wyche

Many of today’s air quality analysers are based on the more traditional point source monitoring technologies, the lesser known DOAS open-path system from Opsis is different and offers many advantages over more conventional methods.

In the paper Differential Optical Absorption Spectroscopy for the Measurement of Air Pollutants produced by DR Kevin Wyche and DR Kirsty Smallbone for project Joaquin (Joint Air Quality Initiative) at the University of Brighton in 2015, they explore its performance when measuring NO2, O3, SO2, HCHO and HONO.

The research concludes that DOAS technology offers an excellent platform to provide high time resolution long term monitoring of air pollutants with high specificity and sensitivity.

Sometimes it’s good to be different.

You can read the full paper here.

Kevin Wyche Paper
By measuring over a wide path, the Opsis DOAS Open-path system gives an average measurement. This means the data is more representative and can be a far more effective technique for applications involving modelling and forecasting which allows for an early warning system for high pollutant episodes so that preventative measures can be taken to reduce the impact.

The Opsis Open-path system can be configured to measure multiple gases in one system including NO, NO2, SO2, O3, Benzene, Toluene, Xylene, Formaldehyde, NH3 etc.

As an internationally approved (MCERTS), multi-parameter, monitoring solution, the Opsis Open-path system really is an emerging future technology for measuring AQ.

In the video below you can see how the Opsis Open-path system has been effective in helping Swansea City Council forecast high pollution episodes which has allowed them to put preventative measures in place to reduce the impact.

For more information on how the Opsis Open-path system can work for you, call to speak to one of our specialists today.

01453 733200

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