In brief
Dust measurement is not a single number; total dust shows all the dust in the air, while the respirable fraction shows the fine part that reaches deep into the lungs. The "respirable dust" in the Regulation on Dust Control corresponds to this fine fraction; some reports, however, use the Turkish word for respirable for all the dust taken in through the mouth and nose. In work involving silica, respirable dust and silica content are measured; in furniture, wood dust is measured; the result directly affects the physician's examination frequency and decisions on chest X-rays.
Why is dust measurement not a single number?
When you open a dust measurement report from the sanding section of a furniture workshop or the sand preparation area of a foundry, you usually find more than one result: "total dust", "respirable dust", and sometimes terms like "respirabl" or "inhalable". Reading the report without knowing which of these results is to be compared with the limit value can lead to false reassurance.
The reason is particle size. Large particles are trapped in the nose and throat; fine particles reach the alveoli, the deepest part of the lungs. In the same environment, total dust may look low while the fine fraction, which is decisive for health, has exceeded the limit.
The Regulation on Dust Control requires the employer to have dust measurements carried out at periodic intervals determined by the risk assessment, to have them repeated when exposure conditions change, and to assess the results against the limit values in Annex 1 (Art. 8). For the scope and measures of the regulation, see our article on the Regulation on Dust Control; this article focuses on the measurement itself.
Total, inhalable and respirable dust: what is the difference?
In dust measurement, airborne dust is collected separated into different "fractions" according to particle size. A different sampling head is used for each fraction:
| Fraction | Names found in reports | Where does it reach in the body? | How is it sampled? |
|---|---|---|---|
| Total dust | Total dust | All the dust in the air; most of it is trapped in the nose and upper airways | Filter cassette with no size selection |
| Fraction taken in through mouth and nose | Inhalable; "solunabilir" in some Turkish reports | All particles that can be breathed in through the mouth and nose | Sampler designed for this fraction |
| Fine fraction | Respirable, respirabl, alveolar; the regulation's "respirable dust" | Down to the alveoli of the lungs | Cyclone sampler that separates out large particles |
This is the source of the terminology confusion in Turkish. The Regulation on Dust Control defines respirable dust (solunabilir toz) as crystalline or amorphous dust with an aerodynamic equivalent diameter of 0.1–5 microns (Art. 4); in other words, the regulation's "solunabilir" is the respirable fraction that reaches deep into the lungs. Some laboratory reports and translations, however, use the word "solunabilir" for the broader fraction taken in through the mouth and nose.
Which fraction is measured for which job?
The fraction to be measured is determined by the type of dust and the health risk it creates. Respirable dust measurement is meaningful for dusts affecting the deep part of the lungs, while total dust measurement is meaningful for monitoring the general dust load and dusts affecting the nose and upper airways.
| Job and dust | Priority measurement | Additional analysis | Why? |
|---|---|---|---|
| Panel sizing, sanding, CNC routing in furniture (wood, MDF) | Total dust; the fraction taken in through mouth and nose as recommended by the laboratory | Wood species information | Hardwood dust falls under carcinogenic substances legislation |
| Foundry sand, natural stone, ceramics, concrete cutting | Respirable (fine) dust | Crystalline silica content | The silica limit is calculated from the quartz content of the dust |
| Metal grinding and welding | Respirable (fine) dust | Analysis of the relevant metals | Separate assessment is needed depending on the metal |
| Flour, feed and grain dust | Total dust | Allergen assessment if necessary | Respiratory sensitisation and asthma risk |
| Suspected asbestos material | Fibre count | — | Limit value 0.1 fibres/cm³ |
The definition of exposure in the risk assessment determines which measurement is needed. For the general framework of measurement requirements, see our article on workplaces where environmental measurements are mandatory.
Silica measurement and wood dust: limit values
Silica measurement requires not only the dust itself but also its content of crystalline silica (quartz, tridymite, cristobalite), because Annex 1 has no fixed limit value for quartz. The limit value is calculated according to the percentage of crystalline SiO₂ in the dust:
- For respirable dust: 10 / (%SiO₂ + 2) mg/m³
- For total dust: 30 / (%SiO₂ + 2) mg/m³
Example: In a granite and natural stone cutting workshop, the laboratory found 25% crystalline SiO₂ in the respirable dust. The respirable dust limit value becomes 10 / 27 = 0.37 mg/m³. If the respirable dust measured by personal sampling is 0.6 mg/m³, the limit value has been exceeded, even though the same result is far below the 5 mg/m³ limit set for inert dust that contains no silica. For the health effects of silica, see our article on crystalline silica dust.
For wood dust, the situation is different. The Regulation on Health and Safety Measures for Work with Carcinogenic or Mutagenic Substances covers work involving exposure to hardwood dust and sets an 8-hour limit value of 5 mg/m³ for hardwood dusts; if the wood dust is mixed with other wood dusts, this value applies to the whole mixture. Exposure and health records under this regulation are kept for at least 40 years after exposure ends (Art. 17). For furniture manufacturers working with hardwoods such as oak, beech and walnut, this directly determines how long measurement reports and health files must be archived.
How is dust measurement planned?
The value of a measurement depends on how accurately it is planned. Follow these steps:
- Work with an authorised laboratory. Dust measurements valid for inspections are carried out by laboratories holding a proficiency certificate from the General Directorate (Art. 8). The laboratory notifies ISG-KATİP, the Ministry's online OHS registration system, of the measurement at least 3 days in advance. Bursa Sistemer does not have its own laboratory; we plan measurements with authorised laboratories.
- Identify similar exposure groups. Employees doing the same work under the same conditions form a group. Sanders, panel sizers and packing staff are separate groups.
- Prefer personal sampling. The sampler is attached to the employee's collar, in the breathing zone. A fixed device placed in the middle of the area does not show what the employee actually breathes.
- Represent the shift. Limit values are 8-hour time-weighted averages. The measurement is made on a day with a normal production pace and covers most of the shift; a measurement taken on a day when production is stopped does not reflect reality.
- Give the laboratory information. Share the safety data sheets of materials, wood species, the shift pattern and the condition of extraction systems.
You can plan the measurement calendar with the OHS calendar. Dust explosion risk is a separate assessment and is not covered by the measurement report; for that, see our article on dust explosion risk.
How to read dust measurement results: an example from furniture
When you receive the dust measurement results, first check the report itself: the fraction measured, the sampling method (personal or area), the sampling time, how the 8-hour average was calculated, the laboratory's proficiency details and whether additional analyses such as silica were carried out. If any of these is missing, ask the laboratory to complete it before interpreting the result.
Example: Personal sampling was carried out on an employee sanding oak panels in a furniture workshop in Bursa. The employee spends 6 hours of the shift at the sanding station and 2 hours in assembly.
- Sanding station, 6 hours: 7.2 mg/m³
- Assembly, 2 hours: 1.0 mg/m³
- 8-hour average = (7.2 × 6 + 1.0 × 2) / 8 = (43.2 + 2.0) / 8 = 5.65 mg/m³
The result exceeds the 5 mg/m³ limit set for hardwood dust. In this case the regulation requires the concentration to be brought below the limit by methods such as preventing dust formation, eliminating it at source or suppressing it, then the measurement to be repeated, and work to be permitted once the concentration is found to have fallen to an acceptable value (Art. 9). The workshop added a downdraught table to the sanding bench and dust extraction connections to the hand sanders; on remeasurement, the 8-hour average was 2.4 mg/m³. In the meantime, employees were given suitable dust masks; the mask is a temporary measure until extraction is installed. For mask selection, see our article on FFP1, FFP2 and FFP3 dust masks, and for extraction arrangements, panel sizing and CNC routers.
How the result feeds into health surveillance
Dust measurement is not just engineering data; the workplace physician's health surveillance plan is based on its result:
- Examination frequency: In dusty work, health surveillance is repeated at a frequency set by the physician, taking into account the risk assessment, the results of periodic dust measurements and the type of dust, and a health record is kept for each employee (Art. 10).
- Chest X-ray: A standard chest X-ray conforming to the ILO classification is taken; for quartz and asbestos exposure, the physician sets the frequency according to the risk, the measurement results and the employee's health. X-rays are read by physicians who have completed ILO reader training (Art. 11).
- Referral: Employees found to be ILO category 0 on X-ray remain under periodic monitoring; those found to be category 1 or above are referred to healthcare providers authorised by SGK (Art. 12).
- Lung function test: Legislation does not set a fixed frequency; the physician decides according to exposure and the level of risk. For details, see our article on the lung function test.
- Work adjustment: Depending on examination and test results, the physician may make recommendations, including that the employee should not be employed in dusty work (Art. 10).
A measurement exceeding the limit value is one of the situations requiring the risk assessment to be renewed regardless of its period. For lung diseases that may develop in dusty work, read our article on pneumoconiosis and dusty work.
In furniture, foundry and stone processing businesses in Bursa and the surrounding provinces, we plan dust measurements with authorised laboratories and enter the results into the risk assessment and the workplace physician's health surveillance plan.
Frequently Asked Questions
How often should dust be measured?
Legislation does not set a fixed period. Measurements are carried out at the periodic intervals determined in the risk assessment, and repeated when conditions affecting exposure, such as machines, materials, the extraction system or work organisation, change.
If the total dust result is low, is silica measurement still needed?
Yes, if your work involves materials containing silica. The silica limit value is calculated according to the quartz content of the dust and can be exceeded at very low values in the fine fraction. A low total dust result alone is no guarantee.
Who can carry out dust measurements?
Measurements valid for inspections are carried out by laboratories holding a proficiency certificate from the General Directorate. The laboratory notifies ISG-KATİP of the measurement at least 3 days in advance.
What is the difference between area measurement and personal measurement?
In personal measurement, the sampler is attached in the employee's breathing zone and shows the dust the employee actually breathes. Area measurement is made at a fixed point and is used to locate the source or to see the effect of a measure. In practice, personal measurement is preferred for comparing an employee's exposure with the limit value.
A risk assessment that identifies and scores hazards on site, links each measure to an owner and a date, and has a clear renewal schedule.
Bursa SİSTEMER OSGB Technical Team — written from the field experience of our OHS specialists and workplace physicians. Legal information is valid as of the publication/update date; contact us for an assessment specific to your business.