If your role involves measuring air quality, you know how crucial it is to capture accurate data and you might be wondering, “are these air quality monitors accurate enough for my project?”. However, determining the accuracy of modern-day air quality monitors is more complex than just knowing their range. To make informed decisions about air quality and protect people, you need a reliable air quality monitor suitable for your specific application. Different types of monitors are out there to choose from:

– Commercial monitors: similar to personal monitors by measuring many parameters, but have been designed to work within the environment with enhanced connectivity and automation capabilities so that you can leave them alone for continuous monitoring
– Reference-grade monitors: often called lab-grade monitors, these are highly accurate but are not practical for most applications as they are very large in size, less user-friendly and significantly more expensive, and are therefore generally reserved for use by governments and scientific research in baseline monitoring
– Consumer-grade monitors: these monitors are the cheapest on the market, but provide less accuracy and features than commercial and lab-grade air quality monitors, making them only suitable for home and personal use

Air quality monitors can come with different sensor types to measure different air quality parameters such as particulate matter, CO2VOCs, and Ozone. Once you have chosen an air quality monitor that measures the parameters relevant to your application, variables such as installation location and placement can affect the accuracy of your data.

So, how accurate do air quality monitors need to be?

It’s worth noting that for air quality monitors used on building sites, commercial or residential settings, having the most precise and accurate reference-grade monitors will not always be essential.

Commercial-grade combines the relative affordability of consumer-grade monitors with the powerful features for the built environment of lab-grade air quality monitors.

When choosing an air quality monitor, your main focus should be on selecting a monitor based on the parameters that you wish to measure, whether you prefer a cloud-based or offline data collection method, which type of software you require to interpret the data, and what your maintenance plan will be to keep your sensors accurate if you plan on long-term monitoring.

That way, with optimal installation location and placement (more on that below), you are in a strong position to gauge the overall quality of the air to make informed decisions and meet health & safety standards, rather than achieving pinpoint precision in measuring a specific pollutant as you would with pricey reference-grade monitors.

Commercial monitors on the market have come a long way, and many use highly accurate sensors such as non-dispersive infrared (NDIR) CO2 sensors (see the TSI BlueSky), which are most suitable for office and commercial settings. For measuring other common outdoor pollutants such as Ozone, many commercial air quality monitors use electrochemical sensors which are less susceptible to cross-contamination with nitrogen dioxide than MOS sensors and provide more consistent readings.

To make the most out of your air quality monitor, ensure that you: 

  • Place monitors in the most frequently occupied spaces, even if that means one in each room for IAQ
  • Install monitors in the zone where people breathe (3-6 meters up from the floor)
  • Place monitors at least 5 meters away from windows, air filters, and diffusers as these can skew results
  • Place at least one monitor on all floors for areas with multiple floors
  • Place enough monitors to cover the entire space for open large spaces

For further information, request a price list here, email london@ashtead-technology.com or call 01462 679 020.

In the following article, Josh Thomas of international equipment specialist Ashtead Technology, sheds light on the dangers of dust on construction sites, Health & Safety Executive (HSE) guidance, emphasises the role that dust monitoring plays in dust control on construction sites, and discusses the types of dust monitors available.


Although progress has been made in reducing the number and frequency of injuries among construction workers, this industry still poses significant risks and is responsible for a sizeable proportion of major and fatal injuries, but what is less recognised are the long-term health problems resulting from day-to-day construction activities.

Construction workers bear the highest occupational cancer rate compared to all other industrial sectors. The industry is responsible for over 40% of occupational cancer deaths and registrations. Every year, past occupational exposures cause over 5,000 cancer cases and around 3,700 deaths. Asbestos is the primary cause of these cancers, accounting for 70%. Silica dusts follow at 17%, and are also responsible for breathing problems and lung diseases that afflict construction workers, making it the second leading cause of death among this demographic. 

In fact, over 500 construction workers are believed to die from exposure to silica dust every year. However, it is important to note that other dusts containing very little to no silica and wood dusts (created from working on softwood, hardwood and wood-based products) are also a danger to health if they are small enough.

Many construction & demolition processes have the potential to create high levels of dust that can lead to diseases like lung cancer, asthmaChronic Obstructive Pulmonary Disease (COPD) and silicosis. These processes include, but are not limited to:

– Cutting paving blocks, kerbs and flags
– Chasing concrete and raking mortar
– Cutting roofing tiles
– Scabbling or grinding
– Soft strip demolition
– Dry sweeping
– Cutting and sanding wood
– Sanding taped and covered plasterboard joints

To ensure safety, it’s important to establish preventative measures that limit exposure to harmful levels. These measures should be clearly outlined in the health and safety document, and regular monitoring should be conducted to demonstrate the effectiveness of these controls.

The Control of Substances Hazardous to Health (COSHH) Regulations require employers to ensure that construction workers are protected against the risks from hazardous construction dusts by following the ‘Assess, Control and Review model‘. Guidance is available from the HSE; see document Construction Dust: CIS 36 and Construction Dust: Specific tasks.

The COSHH definition of a substance hazardous to health includes dust of any kind when present at a concentration in air equal to or greater than 10 mg/m3 8-hour time-weighted average of inhalable dust, or 4 mg/m3 8-hour TWA of respirable dust. This means that any dust will be subject to COSHH if people are exposed to dust above these levels. Some dusts have been assigned specific workplace exposure limits (WELs) and exposure to these must comply with the appropriate limits. For example, the WEL for RCS is 0.1 mg/m3 8-hour TWA.

The role of dust monitoring for dust control on construction sites

Dust exposure monitoring plays a key role in checking that dust control measures are working, and it’s the only way to ensure that WELs comply with COSHH guidelines.

To ensure safety, dust exposure monitoring can be carried out both indoors, within building premises, vehicle cabs, etc., and outdoors, in the surrounding environment of the construction or demolition site. Although the technology for monitoring is similar, each application requires different equipment.

Ashtead Technology also supplies personal air sampling pumps when it is necessary to conduct compliance monitoring, or when the identification and measurement (in a laboratory) of a specific dust type, such as RCS, is required.

Once the dust risks at a construction site have been assessed, ongoing monitoring is more often conducted with direct reading instruments that employ optical techniques to measure the different particulate fractions. Portable battery-powered instruments such as the TSI SidePak and the DustTrak are ideal for this purpose and feature heavily in Ashtead Technology’s fleet of equipment for both sale and rental.

The same dust monitoring technology is employed by fixed units such as the TSI DustTrak Environmental (DTE) or TSI BlueSky, which have been developed specifically for continuous outdoor applications such as dust monitoring on construction sites. 

Fully compliant with stringent MCERTS performance requirements, the DTE employs a ‘cloud’ based data management system, which provides users with easy access to real-time data on dust levels, with the optional addition of other sensors.

Alarm conditions can be set by users so that email alerts are issued when threshold levels arise. The DTE monitors PMTotal, PM10, PM2.5 and PM1.0 mass fractions simultaneously, which provides detailed information on the type of dust present, and means that alarms can be set for specific fractions.

BlueSky air quality monitors are popular choices due to their affordability, and they are also lightweight and easy to install. Each monitor can transmit real-time data to TSI Link Solutions, which allows for secure remote access 24/7. 

One or multiple Bluesky monitors can be set up to create a network of sensors that provide accurate, real-time readings of air quality and dust on site. Additionally, the monitors come with an SD memory card for extra data storage. Optional accessories to go with both BlueSky models include the TSI 12 VDC power solar system and TSI cellular system – both of which enable real-time outdoor air quality monitoring in remote locations.

See the below table for a comparison of the parameters that continuous dust monitors measure.

Continuous dust monitor comparison for dust control

TSI BlueSky 8143TSI BlueSky 8145DustTrak Environmental 8543
Particulate size fractionsPM1, PM2.5, PM4 & PM10PM1, PM2.5, PM4 & PM10 , O3, CO, CO₂, NO2 and SO2PMTotal, PM1, PM2.5 and PM10
Also measuresTemperature and humidityTemperature, humidity and
barometric pressure
Temperature, humidity, plus wind speed and direction with the optional Lufft sensor
Indoor or outdoor monitoringIndoors and outdoorsIndoors and outdoorsOutdoors

It is important to note that dust pollution may be intermittent depending on activity on construction sites, so continuous monitors can identify peaks and thereby assist in the attribution of sources.

Rechargeable batteries and solar panels with the Bluesky or DTE mean that monitors can operate unattended for extended periods in a remote location. With web-based access to the data, site visits are minimised and costs lowered.

Dust control on construction sites summarised

Continuous dust monitoring is the ultimate way of protecting workers as it enables monitoring whilst conditions change significantly on-site and whilst different tools are used, meaning that dust control measures can be reviewed to optimise their effectiveness.

Changes in construction practices and weather can affect environmental conditions on-site, and workplace exposure can be affected by a wide range of factors such as high energy tools which produce a lot of dust, dry weather, not using water to control dust clouds, how enclosed a space is, how long work takes and the frequency.

With a variety of applications for dust monitoring, appropriate technology must be employed, therefore the Ashtead Technology equipment fleet has been developed to meet almost every need, and technical advice is available to help consultants and site managers ensure that dust hazards and effectively managed.

International equipment rental and solutions specialist Ashtead Technology will be attending the Air Quality & Emissions show with TSI Instruments, who they have worked with for over 15 years, on the 12th-13th October 2022.

As a Gold Channel Partner with TSI, Ashtead Technology offers rental and purchase options for TSI’s advanced air quality & dust monitoring equipment. They will be showcasing this equipment range at the event, including the brand new TSI BlueSky  8145 air quality monitor which measures additional gas and weather parameters compared to the standard BlueSky™.

The new BlueSky  8145 can be rented or purchased from Ashtead Technology, alongside a large number of TSI products. Ashtead Technology also offer maintenance and calibration services for the TSI range, during which you can obtain a rental replacement to ensure your air quality & dust monitoring tasks can continue.

What is AQE?

AQE, the Air Quality and Emissions show, is a virtual and in-person event that focuses on Instrumentation and services for air quality and emissions monitoring.

AQE offers a technical program aimed at keeping you up to date with the latest trends, regulations, methods, techniques and technologies.

Furthermore, you can also network with all industry stakeholders including suppliers, regulators and end-users from industry that need to monitor, test and analyse air quality and emissions.

Register your attendance

If you’re thinking of attending AQE 2022, don’t forget to register. Pre-registered visitors can enter FREE to the exhibitions and the technical conferences.

Register here: https://www.ilmexhibitions.com/aqeshow/

Equipment rental

Renting equipment ensures that your air quality monitoring tasks can continue with no sudden stops while your owned equipment is in use, being repaired, or when you simply need more equipment.

Renting equipment also means that you can get your hands on equipment the same or next day, instead of lead times that can take weeks when purchasing.

For further information, browse our website, call 01462 679 020, and see us on stand G3 at AQE.