Fundamentals of Air Quality Monitoring

In this article, we are thinking about the purpose of air quality monitoring and the best monitoring locations, as the two go hand-in-hand.

?Firstly, let’s look at the ‘key drivers’ for monitoring air quality: -

·?????? To help inform design.

·?????? To understand possible health risks.

·?????? To establish the presence of any pollution sources.·?????? For the assessment of compliance against standards, guidelines, planning or permitting requirements.

·?????? Client concerns.

·?????? Assessing mitigation effectiveness.

·?????? Health & Safety requirements.

·?????? For accreditation or certification.

·?????? To determine building and ventilation performance (such as ventilation strategies, material choices, filtration effectiveness).

·?????? Establish and demonstrate Good Practice.

The reason for the monitoring needs to be considered before the location is decided, so that the monitoring is useful and effective.

Secondly, whilst considering the above, when we are thinking about construction sites, we need to look in depth as to the ‘reasons’ for air quality monitoring, which typically include:

• To make sure that nearby homes and businesses are not impacted by dust and fine particulate matter (PM10 and PM2.5) from site activities;
• For checking that mitigation measures on site are appropriate and effective;
• For evidence of any impact the site may have on dust and PM emissions, should there be any complaints; and
• To help on-site staff best manage dust and PM emissions, through setting of trigger / action levels.

Once the reason for the monitoring is understood, a ‘monitoring strategy’ can be put into place and the location and number of monitors can be decided. For example, if the main reason for the monitoring is to make sure that there are no dust emissions impacting a nearby car showroom, then a monitor placed on the site boundary closest to the car showroom will be an ideal location. Measurements should be taken at a height considering breathing zone, e.g. where people are spending most of their time. Placing the monitor on the site boundary will mean that should there be any dust emissions, these will be picked up by the air quality monitor before they reach the showroom. This will trigger an alert to site personnel, and additional mitigation measures can be implemented.

It is useful to understand the typical weather conditions and the prevailing wind direction at your site before deciding on the monitoring locations, as dust and PM can be picked up and moved by the wind. It is useful to always have at least two monitors on site, placed in upwind and downwind locations, to help assign source contribution (i.e. determine if dust emissions are from your site).

If there are other emission sources in the area, such as a busy road or other dusty activities, it can be helpful to locate the monitors away from these wherever possible.

The Institute of Air Quality Management (IAQM) provide guidance on instrument installation requirements in their document Air Quality Monitoring in the Vicinity of Demolition and Construction Sites.

Finally, the practicality of a working site needs to be considered and planned for. Using monitors that are compact, lightweight, easy to install and maintain as well as being able to access the data remotely, and make changes to trigger levels, are key considerations when looking at which equipment to use. The monitors need a permanent power supply; is there battery backup or solar options for the monitor? is there somewhere suitable for the monitor to be fixed to? and are they easily accessible for maintenance and calibration?

Site works can change and monitors sometimes need to be moved. When equipment does not have power or is being moved, this can lead to a loss of data and means that site staff may be unaware of dust and PM emissions and there is then the potential for nearby homes and businesses to be impacted.

For more information on our cloud based and cost-effective Dust & Vibration Monitoring solutions please get in touch with EEMC Monitors.

Emma Gibbons is an associate and air quality specialist supporting EEMC Monitors Ltd.

EEMC Monitors provide Cloud-based Environmental Monitoring Solutions to environmental & engineering specialists, with exceptional value for money.