Community Air Quality Monitoring

A network of PM2.5, PM10 and gas monitoring stations inside the community, calibrated against Pollution Control Department reference stations, measuring wind at the same point, and publishing data in the Thailand Air Quality Index through a public website and LINE Official Account, so the plant and the community work from one set of numbers.

The dust the community sees in an app and the dust the plant measures must be the same number

When the air quality app turns orange, residents look at the nearest stack, even though the government station the app draws from may be tens of kilometres away and the value may come from open burning or regional haze. A plant with no data of its own inside the community is the default defendant every dust season.

The community, in turn, has no number to stand on either. The cheap monitor someone bought and hung on a fence was never calibrated, reads high on humid mornings, and nobody is responsible for its data quality. The result is two sides holding two sets of numbers, neither of which the other accepts.

RE-VEAL designs and installs community air quality stations that are calibrated against reference monitors, measure wind at the same point, and publish one shared data set to everyone through a public website and a LINE Official Account. The goal is not to prove the plant innocent. It is to give the plant and the community one set of numbers to talk about.

Questions this system answers with data

• What is today's PM2.5 in this community, measured here rather than at a government station in another district?
• During the hours the value was high, was the wind coming from the plant or from the fields being burned?
• Does community dust rise only when the plant is operating, or equally on working days and holidays?
• Against the 24-hour standard, how many days did this community exceed the limit during dust season, and is the trend better or worse than last year?
• Did the plant's measures, such as rescheduling material handling or wetting roads, actually lower dust in the community, in numbers?

The limits station data is benchmarked against

Community readings are compared with the Ambient Air Quality Standards under the National Environment Board Notification B.E. 2569, which consolidated all previous notifications into one. The value communities care about most is PM2.5, for which Thailand tightened the limit from 1 June 2566 (2023).

For public communication, the Pollution Control Department issued the Thailand Air Quality Index B.E. 2566 to match the new standard. RE-VEAL stations display the same colours and bands the government uses, so the community never has to translate between two systems.

Reference stations versus sensor stations: the difference, and when to use which

Clause 3 of the B.E. 2569 Notification specifies the accepted measurement method for each pollutant, such as gravimetric, beta attenuation or TEOM for particulates. A legally binding value must come from that class of instrument, which costs millions of baht per station and needs trained staff. Light-scattering sensors cost tens to hundreds of thousands, can be deployed at many points, but produce estimates that must be calibrated.

This approach follows the United States Environmental Protection Agency, which publishes performance targets for PM2.5 sensors used in non-regulatory monitoring, and the World Meteorological Organization's GAW Report No. 293 (2024), which concludes that low-cost sensors are valuable as a network that supplements reference stations, not as a replacement.

What is installed

• PM2.5 and PM10 stations — sensor grades that have passed independent performance evaluation, in weatherproof enclosures designed for airflow without direct sun, with temperature and humidity sensors for correction.
• Gas sensors according to local risk — sulphur dioxide and nitrogen dioxide near boilers and furnaces; hydrogen sulphide and total VOC where odour is also an issue. Selected only where there is a reason, not fitted across the board for appearance.
• Station wind data — wind direction and speed measured at the same point as the sensors, because answering where the dust came from requires wind at that spot, not at an airport some distance away.
• Power and telemetry — solar with battery for sites without mains power; data sent over the mobile network every minute and buffered locally when the signal drops.
• Calibration and quality control — every sensor is collocated with a reference station before deployment, a site-specific correction is built, and sensors rotate back for re-checks on a set cycle.
• Data platform and public website — current values, AQI in the official colours, historical charts and wind direction, in language the community reads easily, plus an operator view of sensor status and data quality.
• LINE Official Account — automatic alerts when a value crosses a set level, a morning daily summary, and the ability for residents to ask for the current value themselves.
• Community display board (optional) — a sign showing the value and colour outside the sub-district office, school or temple, for residents who do not use a smartphone.

Why publishing the data is the point, not an extra

Many plants install stations and keep the data to themselves, fearing it will be used against them. RE-VEAL's experience is the opposite. Data published from day one stops the community guessing, and turns every high-value day caused by something else into the plant's evidence automatically, because everyone can see where the wind was coming from.

What needs careful design is how to publish, not whether. Our system always shows a value with its context: wind direction, the reading at the nearest government station at the same time, and a note when a sensor is under calibration. Data with context is far harder to misread than a bare number.

When dust or odour becomes a complaint, local authorities work under the Public Health Act, not the Factory Act

Department of Health nuisance-complaint statistics for 2569 (2026) show odour as the most complained-about problem at 40.3 percent, ahead of noise at 13.4 percent and dust, soot and smoke at 12.8 percent. The most complained-about sources are residential buildings at 35 percent, followed by businesses hazardous to health under Category 7 at 27.2 percent. Two things follow: dust and odour usually arrive in the same complaint, and many of those complained about are not factories on the Department of Industrial Works schedules. Local officers therefore act under Chapter 5, Section 25 of the Public Health Act B.E. 2535, which lets them order a nuisance stopped without waiting for a Factory Act test result.

The Department of Health sets out the nuisance investigation as a six-step procedure in its EHA 6000 operating standard: preliminary study, preparation of officers and instruments, fact-finding on site, choice of measurement method, conclusion, and determination. It comes with seven forms: Kor.0 for a continuous impact log of at least one week, Kor.1 at the complainant's location, Kor.2 around the source, Kor.3 at the source, Kor.4 for field odour assessment, and Kor.Ror.1 and Kor.Ror.2 for odour concentration measurement. For odour, the deciding criteria are the Public Health Committee Recommendation of B.E. 2560, expressed in D/T units from field olfactometers, which are not the same units as the laboratory odour concentration under the B.E. 2568 Ministerial Regulation.

The RE-VEAL system is therefore designed around this procedure from the start, not adapted after a complaint arrives.

• Stations are sited at the surveillance locations the Department of Health uses: affected residents' homes, schools, religious sites and government offices, positioned downwind of the source.
• The LINE Official Account intake turns each complaint into a data record with date, time, position, the character of the odour or dust, and an intensity of 0 to 5 on the Kor.4 scale, instead of free text that cannot be analysed, and pairs it automatically with the dust reading and wind direction for the same minute.
• Station data is arranged to match forms Kor.1 and Kor.2, and the source's operating data to match Kor.3, so that when officers arrive the plant or sub-district office has a data set that fills the forms immediately.
• Reports follow the three elements the Department of Health uses for a determination: source, pathway and receptor, under Section 25 (4).

A common misunderstanding is that results within the standard prove there is no nuisance. The Department of Health manual is explicit that officers must also weigh how the problem arises, how often it is experienced, and how it affects the complainant's daily life, judged against the living conditions the public should reasonably expect. Bringing only a chemical report is rarely enough; continuous data that shows real frequency and timing is what answers that question.

Calibration and data quality

Light-scattering particulate sensors read high at high relative humidity because particles absorb water and grow. In a Thai climate where morning humidity above 90 percent is normal, an uncorrected sensor reports inflated dust every morning, and the community wakes up to orange on a clean day.

• Before deployment, every sensor is collocated with a reference station for at least 30 days, following US EPA guidance, using at least three units per model to assess unit-to-unit agreement.
• A site-specific correction including humidity is built. Published values are corrected values; raw values are retained for audit.
• During operation, agreement between stations in the network is checked automatically. A station that diverges abnormally from its neighbours is flagged for the operator.
• Sensors rotate back for re-collocation on the cycle set in the agreement, and sensor modules are replaced by service life rather than after failure.
• A monthly data quality report states data completeness, collocation results, and any periods excluded, with reasons.

Deliverables

• Network design report giving each station location and the rationale, based on prevailing wind, source positions and where residents are concentrated.
• Installed and commissioned stations, with collocation results against the reference station and the site-specific correction.
• Public display website and LINE Official Account, with alerts and daily summary messages configured.
• Baseline report from the initial data collection period, for comparison during dust season and after mitigation measures.
• Monthly report: averages, days above the limit, high-value events with wind direction, and data quality, in a form usable for EIA reporting or community meetings.
• Training for plant staff and for community or sub-district representatives to read and use the data themselves.

Process and schedule

Roughly three to four months from start to a system the community can use. The collocation phase cannot be shortened: it has to span enough variety in humidity and dust levels. To be ready for dust season, work should start no later than September.

Limitations we state before quoting

• Sensor station values are not legal values. Comparison with the B.E. 2569 standard requires the methods specified in Clause 3. Sensor stations are for surveillance, communication, and pointing to where and when reference-method measurement should be made.
• Community dust is the sum of all sources: the plant, traffic, open burning and regional haze. A station tells you the value and where the wind came from; apportioning how much came from whom needs dispersion modelling or compositional analysis alongside it.
• During northern haze season or sugarcane burning, values are high across the whole region regardless of the plant. The system shows the nearest government station side by side to make this visible, but do not expect the station to make the numbers look good in those weeks.
• Sensors last roughly one to two years in Thai conditions and drift along the way. Re-check and replacement cycles belong in the agreement; an install-and-forget network produces wrong data while the screen keeps showing numbers.
• Publishing needs a clear policy from the start: who can see what, how values under calibration are shown, and who answers questions when values are high. We help draft that policy, but the decision is the client's.

Who this service is for

• Plants whose EIA or EHIA measures require ambient air monitoring in surrounding communities and that want continuous data instead of twice-yearly sampling
• Plants and biomass power stations facing dust complaints that need data the community will accept
• Industrial estates and operating zones wanting a network of stations around the perimeter on one standard
• Mines, quarries, bulk-cargo ports and large construction projects where dust is the main issue
• Sub-district administrative organisations, municipalities and provincial administrations wanting stations where Pollution Control Department coverage does not reach, with a public alert channel
• Schools, hospitals and elderly care centres that need real local values to decide on outdoor activity

Commonly combined with

• AERMOD dispersion modelling — to apportion how much of the measured community dust comes from the plant, and to use station data to validate the model.
• Continuous emission monitoring at the stack (CEMS) — with stack data and community data at the same time, the plant can answer whether a high-value event in the community coincided with a stack release.
• Odour fingerprint monitoring and source identification — for communities with both dust and odour issues, sharing station infrastructure and the data platform.

Getting started

Send us the basics: the site location, the type of operation or source of concern, the distance to the nearest community, and the channels the community already uses. Our team will assess the number and placement of stations, the parameters worth measuring and the publication approach, and return a fee proposal and schedule within three working days, at no cost at that stage.

Free initial consultation · Request a proposal

References

1. National Environment Board Notification on Ambient Air Quality Standards, B.E. 2569. Government Gazette, Vol. 143, Special Part 20 Ngor (21 January 2026).
2. Pollution Control Department Notification on the Thailand Air Quality Index, B.E. 2566. https://www.pcd.go.th/pcd_news/30028/
3. National Environment Board Notification on the PM2.5 ambient standard (in force 1 June 2023), summarised by the Faculty of Environment and Resource Studies, Mahidol University. https://en.mahidol.ac.th/envinews/434-pm-2-5-37-5-1-66
4. Public Health Act B.E. 2535, Chapter 5 (Nuisance), Section 25.
5. Public Health Committee Recommendation on Criteria and Methods for Investigating Odour Nuisance from Businesses Hazardous to Health, B.E. 2560.
6. Department of Health, Bureau of Environmental Health. Technical manual: Guidelines for investigating odour nuisance for officers under the Public Health Act.
7. Department of Health, Bureau of Environmental Health (2026). Training material: Odour measurement and control at businesses hazardous to health (Tuangsit Wimuktayon) — nuisance complaint statistics and the EHA 6000 standard.
8. Ministerial Regulation Prescribing Odour Standards in Air from Factories, B.E. 2568. Government Gazette, Vol. 142, Part 21 Kor (27 March 2025).
9. U.S. Environmental Protection Agency (2021). Performance Testing Protocols, Metrics, and Target Values for Fine Particulate Matter Air Sensors. EPA/600/R-20/280. https://www.epa.gov/air-sensor-toolbox
10. World Meteorological Organization (2024). GAW Report No. 293: Integrating Low-cost Sensor Systems and Networks to Enhance Air Quality Applications. https://library.wmo.int/