TL;DR
- Dubai Municipality published DM-HSD-GU141-IAQI2 on 14 February 2025 — an official Environmental Indoor Air Quality Index. It is a first issue, superseding nothing.
- It converts ten parameters into a single score from 0 to 500, in six colour-coded bands from Good to Hazardous.
- The method is fully specified: per-pollutant breakpoints, linear interpolation, weighting factors, and two different calculation modes — one for real-time alerts, one for reporting.
- Appendix 1 sets out requirements the document itself describes as legally enforceable: continuous IoT monitoring with real-time transmission, regulator access to the data, ISO 17025 calibration, tamper-proof logging and five years of data retention.
- This is not the same document as DM-HSD-GU119. GU119 gives the limits; GU141 gives the index and the rules for the monitoring system. You need both.
Every IAQ vendor in the UAE displays a proprietary "health score" or "air score" out of 100. Dubai Municipality has published its own index, on a different scale, with a defined formula — and it has been in circulation for over a year. If your building reports a vendor score and the regulator asks for EIAQI, those are not the same number and cannot be converted into one another by eye. This page reproduces the method so you can check whether what you are being shown is the regulator's index or somebody's marketing metric.
1. What EIAQI is
DM-HSD-GU141-IAQI2 — Environmental Indoor Air Quality Index (EIAQI)
Health & Safety Department, Environmental Health Section · Version 1 · Issue date 14 February 2025 · Open Data
The guideline describes EIAQI as a metric for evaluating and communicating indoor air quality across building types. Its stated departure from conventional practice is this: instead of assessing each pollutant against its own threshold in isolation, EIAQI integrates multiple parameters into one index.
The document also distinguishes itself explicitly from the outdoor air quality index. Outdoor AQI addresses ambient atmospheric conditions; EIAQI addresses variables specific to enclosed spaces — building materials, ventilation effectiveness, occupant activities and localised pollution sources.
The ten parameters
Eight pollutants and two comfort parameters:
| Group | Parameters |
|---|---|
| Particulate | PM2.5, PM10 |
| Gaseous | CO2, CO, VOCs, formaldehyde (HCHO), NO2, O3 |
| Thermal comfort | Temperature, relative humidity |
This list is the first practical filter. A monitoring installation that measures five or six parameters cannot produce a complete EIAQI — and because the real-time mode takes the maximum of all sub-indices, a missing parameter can be precisely the one that would have been dominant. The resulting score is not merely incomplete; it is biased low.
2. The six categories
| Score | Category | Colour | Health impact as stated |
|---|---|---|---|
| 0–50 | Good | Green | Indoor air quality is healthy, no risk |
| 51–100 | Moderate | Yellow | Acceptable, but some pollutants may pose a concern |
| 101–150 | Unhealthy for Sensitive Groups | Orange | Individuals with respiratory conditions, children, elderly may experience effects |
| 151–200 | Unhealthy | Red | Increased health risks, discomfort for occupants |
| 201–300 | Very Unhealthy | Purple | Severe health effects; mitigation required |
| 301–500 | Hazardous | Maroon | Dangerous indoor air quality; immediate intervention needed |
Note the direction of travel: lower is better. This is the opposite of the "health score out of 100" convention most vendor dashboards use, where higher is better. A building showing 92 on a vendor scale and a building showing 92 on EIAQI are in completely different conditions — the first is close to ideal, the second sits in the Moderate band.
3. Breakpoints
Each pollutant has its own concentration bands mapped to the index bands:
| Index band | PM2.5 µg/m³ | PM10 µg/m³ | CO2 ppm | CO ppm | VOCs mg/m³ | HCHO µg/m³ | NO2 ppb | O3 ppb |
|---|---|---|---|---|---|---|---|---|
| 0–50 · Good | 0–12 | 0–50 | 400–600 | 0–4 | 0–0.3 | 0–50 | 0–50 | 0–50 |
| 51–100 · Moderate | 12.1–35 | 51–100 | 601–1000 | 4.1–9 | 0.31–0.6 | 51–80 | 51–100 | 51–100 |
| 101–150 · USG | 35.1–55 | 101–150 | 1001–1500 | 9.1–15 | 0.61–1 | 81–100 | 101–150 | 101–150 |
| 151–200 · Unhealthy | 55.1–150 | 151–250 | 1501–2500 | 15.1–30 | 1.1–1.5 | 101–300 | 151–200 | 151–200 |
| 201–300 · Very Unhealthy | 150.1–250 | 251–350 | 2501–5000 | 30.1–50 | 1.51–2 | 301–500 | 201–300 | 201–300 |
| 301–500 · Hazardous | >250 | >350 | >5000 | >50 | >2 | >500 | >300 | >300 |
Thermal comfort bands
| Index band | Temperature °C | Relative humidity % | Thermal sensation |
|---|---|---|---|
| 0–50 | 22 – 25.5 | 40 – 60 | Comfortable |
| 51–100 | 20–21.9 or 26–28 | 35–39.9 or 60.1–65 | Slight discomfort |
| 101–150 | 18–19.9 or 28.1–30 | 30–34.9 or 65.1–70 | Discomfort |
| 151–200 | 16–17.9 or 30.1–32 | 25–29.9 or 70.1–75 | Significant thermal stress |
| 201–300 | 14–15.9 or 32.1–34 | 20–24.9 or 75.1–80 | Severe discomfort |
| 301–500 | below 15.9 or above 34 | below 20 or above 80 | Extreme discomfort |
One caution worth stating plainly: the comfort humidity band here (40–60%) is narrower than the range in DM-HSD-GU119, which gives a recommended 20–60%, and different again from DM-HSD-GU142 on mould, which asks for below 60% and ideally 30–50%. These are three documents from the same department with three different humidity figures for three different purposes. A report that shows a humidity verdict without naming which document it is judged against is not telling you enough.
4. How the score is calculated
Step 1 — sub-index per parameter
Each measured concentration becomes a sub-index by linear interpolation within its band:
Ip = (C − CL) ÷ (CH − CL) × (IH − IL) + IL
where C is the measured concentration, CL and CH are the lower and upper concentration limits of the band, and IL and IH are the lower and upper index values of that band. Results are rounded to the nearest whole number — below 0.5 down, 0.5 and above up.
Step 2 — two different answers, for two different purposes
| Real-time EIAQI | Weighted EIAQI | |
|---|---|---|
| Formula | EIAQI = max(Ip1, Ip2 … Ipn) | Iw = Ip × Wp |
| Frequency | At the end of each hour | 8-hour and 24-hour |
| Purpose as stated | Immediate regulatory alerts and intervention | Detailed compliance reporting to regulatory agencies and stakeholders |
| Logic | The worst pollutant dictates the result — the dominant pollutant approach | Each sub-index scaled by its health-impact weight |
Weighting factors
| Parameter | Weight | Justification given in the guideline |
|---|---|---|
| PM2.5 | 0.25 | Highest risk pollutant for respiratory and cardiovascular health |
| PM10 | 0.14 | Coarse particulates, slightly lower risk than PM2.5 |
| CO2 | 0.13 | Ventilation indicator; linked to cognitive decline at high levels |
| CO | 0.08 | Acute toxicity; carbon monoxide poisoning risk |
| VOCs | 0.08 | Strong indoor exposure source — furniture, paint, cleaners |
| Humidity | 0.08 | Strong impact on mould growth, asthma and air quality perception |
| HCHO | 0.07 | Carcinogen; respiratory and neurological effects |
| NO2 | 0.07 | Combustion pollutant; respiratory inflammation |
| Temperature | 0.06 | Thermal comfort, linked to occupant productivity |
| O3 | 0.04 | Less common indoors but oxidative and irritative |
The weights sum to 1.00. Note what the ordering implies: CO2 carries barely half the weight of PM2.5. Much of the UAE IAQ market sells on CO2, because it is the cheapest parameter to measure well. The regulator's own weighting says particulates matter more.
5. The requirements in Appendix 1
Appendix 1 opens by stating that data collection and monitoring shall adhere to the following legally enforceable requirements. In full:
| Requirement | As specified |
|---|---|
| Continuous monitoring | Parameters shall be monitored continuously using IoT-enabled or smart sensors providing real-time data transmission |
| Logging | Automated data logging with timestamps, for traceability and compliance reporting |
| Regulator access | Real-time data shall be accessible to regulatory authorities for verification and enforcement |
| Averaging windows | 1-hour for acute risk and short-term exposure limits; 8-hour and 24-hour for trend analysis and compliance |
| Automation | The system shall automatically aggregate exposure data and generate compliance reports against DM thresholds |
| Spatial coverage | Occupied spaces plus ventilation inlets and outlets. Placement determined by risk assessment, building size, occupancy density and HVAC design |
| Calibration | All devices calibrated and certified in accordance with ISO 17025, with routine validation by accredited laboratories or authorised providers |
| Data integrity | Tamper-proof logging mechanisms and cybersecurity protocols |
| Detection capability | Sensors must detect and quantify all ten regulated parameters at regulatory detection limits |
| Retention | Data stored securely for a minimum of five years to ensure regulatory auditability |
| Reporting | Compliance reports generated automatically at predefined intervals — hourly, daily, monthly — and submitted to the authority when required |
High-risk occupancies — the guideline names schools and elderly care homes — are additionally required to implement enhanced monitoring protocols and mitigation strategies.
Read as a procurement specification, Appendix 1 disqualifies most of what is sold as "IAQ monitoring" in this market. A handheld meter and an annual PDF fails on continuity. A consumer-grade sensor on Wi-Fi fails on ISO 17025 calibration and on tamper-proof logging. A cloud dashboard with a 90-day data window fails on five-year retention. A system measuring CO2, PM and TVOC only fails on detection capability. These are not our criteria — they are the regulator's, published in February 2025.
6. How EIAQI sits alongside the other documents
| Document | What it provides |
|---|---|
| Dubai Law 5/2025, Art. 33 | The legal duty. The owner must measure indoor air and provide the measuring devices |
| Local Order 11/2003, Art. 56 & 86 | The older duty, still in force, and the enforcement powers — including cutting water and electricity for up to three months |
| DM-HSD-GU119 v4 | The permissible limits per pollutant, split into new buildings and existing buildings |
| DM-HSD-GU141 (this document) | The index, the calculation method, and the requirements for the monitoring system itself |
None of the four replaces the others. A compliance position built on the limits alone, without the index, is incomplete — and one built on a vendor's proprietary score, without either, is not a compliance position at all.
7. Practical checklist
- Ask what index your current system reports. If the answer is a number out of 100 where higher is better, it is not EIAQI.
- Count the parameters. Fewer than ten means the index cannot be complete, and the real-time mode will under-report.
- Ask for the calibration certificates and check they reference ISO 17025 and an accredited laboratory.
- Ask how long the data is kept. Five years is the stated minimum.
- Ask whether the log can be edited. Appendix 1 requires tamper-proof mechanisms; a spreadsheet export is not one.
- Check the sampling points against the layout — occupied spaces plus ventilation inlets and outlets, sized by risk assessment.
- Confirm reports generate automatically on a schedule, rather than being assembled by hand when an inspector asks.
Common questions about EIAQI.
What is EIAQI?
The Environmental Indoor Air Quality Index, defined in Dubai Municipality guideline DM-HSD-GU141-IAQI2, version 1, issued 14 February 2025. It converts ten indoor parameters into a single score from 0 to 500, in six colour-coded categories from Good to Hazardous.
Which parameters does EIAQI include?
Ten. Eight pollutants — PM2.5, PM10, CO2, CO, VOCs, formaldehyde, NO2, O3 — plus temperature and relative humidity. A system measuring fewer than ten cannot produce a complete index.
How is the score calculated?
Each parameter is converted to a sub-index by linear interpolation between its band breakpoints. The guideline then defines two modes: for real-time alerts, the hourly EIAQI is the highest sub-index across all parameters; for 8-hour and 24-hour compliance reporting, each sub-index is multiplied by its weighting factor, with PM2.5 weighted highest at 0.25.
Is EIAQI monitoring mandatory?
Appendix 1 of the guideline states that data collection and monitoring shall adhere to requirements it describes as legally enforceable — continuous IoT monitoring with real-time transmission, regulator access, ISO 17025 calibration, tamper-proof logging, five-year retention and automatically generated reports. How that is enforced in practice is a question for Dubai Municipality; the wording of the document is unambiguous.
How does EIAQI relate to DM-HSD-GU119?
They are complementary, not alternatives. GU119 sets the permissible limit per pollutant. GU141 defines the index, the calculation and the requirements for the monitoring system. Compliance work needs both.
Is EIAQI the same as the outdoor air quality index?
No. The guideline distinguishes them explicitly: outdoor AQI addresses ambient atmospheric conditions, while EIAQI is built for indoor variables — building materials, ventilation effectiveness, occupant activities and localised sources.
Why does the humidity range differ between documents?
Because they answer different questions. EIAQI treats 40–60% as the comfortable band. GU119 gives a recommended 20–60% with ceilings tied to temperature. GU142 on mould asks for below 60%, ideally 30–50%. All three are Dubai Municipality documents; a report should state which one a verdict is based on.