PM10 - IMPORTANT UPDATE - Short Summary of the IAQM “Position Statement: Low‑Cost Sensor (LCS) Systems PM Monitoring” (September 2025)

Dr Steven J Goodman
Oct 7
4 min read

If you’re using or specifying low-cost PM₁₀ sensors, this statement raises the bar: they’re no longer “good enough by default.” Users must prove suitability and performance under site-specific dust conditions, or risk non-compliance with IAQM expectations.

Purpose & Scope

The Institute of Air Quality Management (IAQM) issues this statement to clarify its position on using low‑cost sensor (LCS) systems for PM₁₀ monitoring around demolition and construction sites.
It is focused only on PM₁₀, not PM₂.₅.
This guidance is relevant especially where elevated PM₁₀ concentrations may occur (e.g. due to dust during construction).
The position is intended to support IAQM members and others in applying IAQM’s existing guidance and Code of Practice.

Key Issues & Concerns with LCS Systems

Indicative nature & limitations LCS systems are “indicative” and are not currently suitable for compliance reporting against formal air quality objectives or legal limits. They are rarely developed for high PM₁₀ concentration events; many are calibrated for “typical ambient” conditions. Some LCS units under‑report PM₁₀ when concentrations approach or exceed the IAQM’s site action level (190 µg/m³).
Standards & certification gaps Current standards (e.g. MCERTS, PD CEN‑TS 17660‑2:2024) or codes (PAS 4023:2023) are designed for ambient conditions, not necessarily the elevated dust levels around construction sites. MCERTS’s new Product Certification Bulletin PC4 (from July 2025) restricts the usable range of indicative sensors (max 150 µg/m³ 1‑hour mean), which is below the IAQM’s action level. Some sensor manufacturers apply algorithms or filtering that remove peaks (i.e. “clean noise”), which can mask real short‑term spikes.
Sensor design & performance Performance varies by sensor type, configuration (e.g. path length, heated inlet), and algorithm. Many sensors lack independent validation in high dust / coarse particle settings typical of construction sites. Humidity, coarse dust loading, and environmental conditions may degrade accuracy.

Recommendations & IAQM Position

Use of LCS should be justified: LCS systems should only be used when they can reliably meet the monitoring objectives (e.g. detect exceedances) and their limitations are understood and documented.
Evidence requirement: Users must gather and present independent evidence showing the sensors’ ability to detect elevated concentrations in relevant site conditions, especially around the IAQM action level.
Not sufficient to rely on certification alone: MCERTS or other certification is not enough to guarantee suitability for dusty construction contexts.
When LCS are used:
Encouragement to manufacturers: Publish independent performance data for LCS systems in high‑dust environments, to support users.
Recognise the utility but caution: LCS systems may help increase spatial coverage and provide early alerts, but caution is needed not to over‑interpret their data or rely on them for compliance.

The IAQM Position Statement (2025) on low-cost PM₁₀ monitoring has significant implications for how LCS (Low-Cost Sensor) systems are used on construction and demolition sites. Here are the key takeaways and their implications:

🔍 1. LCS Systems Are Not Automatically Suitable

Implication: Simply having a low-cost PM₁₀ sensor on site is not enough to meet best practice standards.

IAQM makes it clear that not all LCS are fit for purpose, especially in dusty construction environments.

Certification (e.g., MCERTS) does not guarantee the sensor can handle elevated dust events.

👉 Action: Users must independently validate the suitability of the chosen sensor for construction-specific monitoring, especially for short-term dust spikes.

📏 2. Action Levels Must Reflect Sensor Capabilities

Implication: If LCS systems can’t detect up to the 190 µg/m³ IAQM action level, lower site-specific action levels must be used.

IAQM’s standard trigger level (190 µg/m³ 1-hour mean) might not be detectable by many LCS devices.

Some sensors have upper detection limits around 150 µg/m³ or lower.

👉 Action: If using LCS systems, project teams must:

Adjust action thresholds downward

Justify and document how and why thresholds were changed

🧪 3. Calibration and Performance Evidence Are Required

Implication: LCS sensors must be supported by independent performance data, specifically for construction-like conditions.

Most LCS systems are calibrated in ambient urban environments, not dusty, coarse particle environments like construction sites.

Without validation, they may under-report high PM₁₀ concentrations, leading to false confidence.

👉 Action: Project teams must:

Request independent lab/field validation from manufacturers

Avoid relying solely on internal or lab-only calibration data

📉 4. Filtered Data May Hide Real Dust Events

Implication: Some LCS devices use algorithms to "clean up" noisy data, potentially masking actual dust spikes.

Devices that apply heavy smoothing or filtering may miss real-time exceedances.

That undermines the purpose of real-time dust monitoring on construction sites.

👉 Action: Use systems that provide raw or minimally filtered data, and ensure transparency in how data is processed.

🔧 5. Regulatory and Developer Expectations Will Tighten

Implication: Local authorities, developers, and consultants are likely to tighten expectations on how LCS are used and validated.

IAQM guidance shapes industry best practice and is often adopted by planning authorities.

There will be greater scrutiny of dust monitoring plans using LCS systems.

👉 Action: Environmental consultants and contractors must be prepared to defend their monitoring strategy with robust evidence, not just cost-efficiency.

✅ 6. Opportunities Still Exist – with Caution

Implication: LCS can still be valuable for:

Screening, trend tracking, and early alerts

Filling spatial gaps in coverage

...but not for compliance or triggering enforcement unless appropriately validated.

👉 Action: Use LCS systems as supplementary tools, not primary compliance monitors — unless their performance has been proven for high-dust contexts.

If you’re using or specifying low-cost PM₁₀ sensors, this statement raises the bar: they’re no longer “good enough by default.” Users must prove suitability and performance under site-specific dust conditions, or risk non-compliance with IAQM expectations.

For monitors that meet the IAQM spec, please see the IPM Plus:

https://www.environst.com/ipmplus