Alphasense OPCs can help achieve the UK’s new PM2.5 target

On 16th March 2022, the UK government announced new targets to reduce the acceptable airborne level of PM2.5 particulate matter to 10 micrograms per cubic metre by 2040.

Poor air quality caused by high levels of airborne particulates has been consistently linked with higher rates of cancer, respiratory disorders, heart attacks, depression and infertility, especially in urban environments. The new government guidelines are designed to reduce the risk of these conditions by halving the number of acceptable PM2.5 particles in the air to 10 micrograms per cubic metre.

Over the next 18 years, local governments and regional councils will be responsible for achieving the new target by actively monitoring air quality and introducing new schemes and initiatives to reduce levels of harmful airborne particulates in urban environments and public spaces.

Key to achieving these targets will be the widespread use of high-accuracy, low-cost air quality monitoring devices in both outdoor and indoor locations. These instruments offer a reliable, affordable option for schools, councils, institutions or private companies tasked with measuring the number of airborne PM2.5 particles in a given environment.  

The Alphasense OPC-N3 and OPC-R2 Optical Particulate Counter (OPCs) are designed to offer high accuracy, low-cost options for air quality instruments that monitor dangerous airborne particulates. Both devices can detect and count particles at sizes PM1, PM2.5, PM10 and PM4.25 (as an option), and both devices output their readings as digital data using the software supplied with them.


The OPC-N3 measures particles sized 0.35μm to 40μm (including pollen) and sorts them into 24 different-sized ‘bins’ for efficient reporting. The N3’s ability to measure up to 2,000 µg/m3 makes it ideal for a number of different indoor and outdoor air quality applications designed to monitor PM2.5 concentrations.

OPC-N3 particle size derivative comparison graph


The OPC-R2 is a smaller device with lower power consumption that is still capable of measuring particles sized 0.30μm to 12.4μm and sorting them into 16 ‘bins’. Measuring just 72mm (long) by 20.5mm (wide) the OPC-R2 is well-suited to portable air quality applications and devices using multiple gas sensors, where space inside the device is at a premium.

As demonstrated by the OPC-R2 comparison graph below, the OPC-R2 and OPC-N3 perform at similarly high levels to other leading OPC devices costing hundreds or even thousands of pounds more. The impressive performance of both Alphasense OPC devices at their sizes and price points was also reflected in a recent report conducted by California-based South Coast AQMD that included both the OPC-N3 and OPC-R2 in an evaluation of the performance of low-cost air quality sensors. Both devices punch well above their weight when it comes to performance and customer expectations. You can read more about the AQMD report at:

OPC-R2 Comparison of PM2.5 monitoring with TSI OPS 3330 and DustTrak instruments

At Alphasense, we will continue to work closely with our air quality clients and partners to support the widespread production and adoption of high-quality, low-cost instruments and devices for monitoring PM2.5 and other harmful airborne gases and particulates.

To find out more information about Alphasense OPC products or gas sensors, please visit our products page

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