Air Quality Data You Can Defend: How Airly Earns Its Credibility

Any sensor can claim to precisely measure air quality. Far fewer can prove it. At Airly, quality assurance is not a marketing statement – it is a documented, independently verified process that runs from factory calibration to continuous field validation. Here is what that means in practice.

A reference station on our premises – test in real conditions

Before any Airly sensor reaches a customer, it undergoes a two-week colocation test alongside a certified reference station located at our headquarters in Kraków. This is not a controlled chamber test but real-world ambient air, with the same mix of traffic, weather, and seasonal variation that sensors will face in the field.

During this period, each device is validated against regulatory-grade reference measurements for particulate matter (PM2.5, PM10) and gaseous pollutants. Each sensor leaves with an individual calibration certificate, a device-specific document confirming its actual performance.

Airly is the only air quality sensor manufacturer in Poland to perform continuous colocation testing at a permanent on-site reference station. That infrastructure matters: it means quality is not an occasional check but a structural part of how we operate.

MCERTS: independently verified performance

MCERTS is the UK Environment Agency’s monitoring certification scheme – one of the most rigorous performance frameworks for environmental sensors in Europe. Achieving MCERTS certification means that an independent body has confirmed a device meets strict criteria for accuracy, repeatability, and data quality. These criteria are validated across both laboratory and field conditions.

Airly sensors hold MCERTS certification for PM2.5 and PM10 measurements. For public sector organisations, particularly in the UK and increasingly across Europe, this certification is a credibility marker that regulatory bodies and procurement teams recognise. It separates independently tested equipment from self-declared performance claims.

CEN/TS 17660: meeting the emerging European benchmark

CEN/TS 17660 is the European pre-normative technical specification for air quality sensor performance, commissioned by the European Commission. It defines performance classes – similar in concept to energy ratings – that allow sensors to be evaluated against a consistent, cross-border standard.

Airly sensors achieve accuracy close to the Class 1 criteria of CEN/TS 17660 for PM2.5, PM10, NO₂, and O₃. As the EU’s Ambient Air Quality Directive (AAQD 2024) references this specification, Class 1 performance will become a key threshold for indicative measurement systems used in official monitoring networks.

PAS 4023: good practice across the full deployment lifecycle

PAS 4023 is the British Standards Institution specification for the deployment and quality control of low-cost outdoor air quality sensor systems. Developed with support from DEFRA, it covers the full project lifecycle. This includes everything from project design and sensor selection through to calibration, network maintenance, and data validation.

Airly’s processes are aligned with PAS 4023 at every stage. Our deployments follow rigorous siting criteria – accounting for airflow, mounting height, and interference risks. Additionally, our data science team runs continuous QA/QC on every device. This ensures measurements remain stable and defensible long after installation.

Cyber Essentials: data security as a baseline

Environmental monitoring infrastructure increasingly runs on connected digital systems. Airly holds Cyber Essentials certification – the UK government-backed scheme that independently validates an organisation’s security controls. These include firewalls, access management, patch management, and malware protection.

For public sector buyers and regulated entities, this certification provides procurement confidence that data integrity and system security have been assessed by an external body – not only declared.

Designed for AAQD 2024 and WHO guidelines

Airly’s quality framework is deliberately built to serve both EU and non-EU contexts. Our calibration and performance validation align with WHO air quality guidelines, AAQD 2024 requirements, and the CEN/TS 17660 framework – meaning the data Airly provides is relevant for compliance, planning, and public reporting whether a city is working toward EU regulatory thresholds or international health-based benchmarks.

Quality is earned, not declared

Every Airly sensor leaves our facility with a documented calibration record, tested against a reference station, with performance validated against recognised standards. The certifications are external confirmation of what our internal processes already require.

Documented quality is not a minute detail. It is the main requirement.