Dust at Work and What It Does to Your Lungs
An occupational doctor explains respirable dust, silica limits, the diseases that follow years later, and the controls and health checks that prevent them.
The short version
- The dust that harms you is mostly the dust you cannot see. Respirable particles under about 4 micrometres, which travel past the airways into the gas-exchange region of the lung.
- Respirable crystalline silica is the most dangerous common workplace dust, with an occupational limit of 50 micrograms per cubic meter over 8 hours in the US and 0.1 mg per cubic meter in the UK.
- Silicosis, occupational COPD and occupational asthma develop quietly over years, so the point of health surveillance is to catch the change before you notice symptoms.
See a doctor promptly if
These are the signs that change this from something to read about into something to act on.
- Breathlessness on exertion that is worse than it was a year ago, or a cough lasting more than three weeks
- Wheeze, chest tightness or cough that improves on days off and rest days and returns at work. The classic pattern of occupational asthma
- Coughing blood, unexplained weight loss, or fever and night sweats in anyone with a silica history: needs prompt assessment, including for tuberculosis
Fine dust that you cannot see is the dust that damages lungs. Particles below roughly 4 micrometres, the respirable fraction, bypass the nose and airways and settle in the alveoli, where the body cannot clear them easily, and where the inflammatory response to them causes permanent scarring over years.
Coarse visible dust is mostly a nuisance and an irritant. The invisible fraction is the health hazard, which is why exposure is measured with sampling pumps rather than judged by eye.
The exposures that matter most#
Respirable crystalline silica. From concrete, stone, brick, sand, engineered worktops, foundry sand and abrasive blasting. The US permissible exposure limit is 50 µg/m³ as an 8-hour average, with an action level of 25 µg/m³. The UK workplace exposure limit is 0.1 mg/m³, which is 100 µg/m³. Both numbers are small; a few minutes of dry cutting can exceed them for the whole shift.
Wood dust, particularly hardwood, which is classified as a human carcinogen and is associated with nasal cancer as well as asthma.
Flour and grain dust, one of the commonest causes of occupational asthma.
Welding fume, reclassified as carcinogenic to humans, and a cause of metal fume fever and airway disease.
General inhalable and respirable nuisance dust, controlled in the UK at 10 mg/m³ inhalable and 4 mg/m³ respirable as 8-hour averages. Those are ceilings for otherwise low-toxicity dust, not targets to aim at.
What the diseases look like#
Silicosis and other pneumoconioses cause progressive breathlessness and cough, usually with a long latency, and there is no treatment that reverses the scarring. Occupational COPD accounts for a meaningful share of all COPD, including in people who never smoked. Occupational asthma is the one to catch early: if it is identified and exposure stops within the first year of symptoms, many people recover substantially; if exposure continues, the asthma often becomes permanent.
The pattern that should always trigger a conversation is symptoms that ease on holiday and return within a day or two of going back.
Controls that actually reduce exposure#
The order matters, and personal protective equipment comes last.
- Eliminate or substitute. Buy pre-cut material, use a less hazardous abrasive than silica sand.
- Engineering controls. On-tool extraction, water suppression for cutting and grinding, enclosure of the process, and properly designed local exhaust ventilation tested at least annually.
- Administrative controls. Restrict who is in the dusty area, schedule dusty work when fewest people are present, use vacuum with HEPA filtration rather than sweeping or compressed air.
- Respiratory protection. Matched to the measured exposure, fit tested, and part of a written program.
Health surveillance, and why it is for you#
Where a real exposure exists, surveillance is a legal duty in most jurisdictions: a baseline and periodic respiratory questionnaire, spirometry, and chest imaging at defined intervals for silica work. Its purpose is to detect a falling trend in lung function while it is still small, and to prove what your lungs were like when you started. Ask for your numbers each time and keep them.
Where to take this next#
Dust and noise are the two exposures where the damage is silent, cumulative and completely preventable, and both rely on the same discipline of measurement, control and surveillance. The full guide to hearing loss and noise at work sets out how that discipline works in practice.
Common questions
If I cannot see dust in the air, am I safe?
How long does silicosis take to develop?
Does smoking make occupational dust worse?
Sources
Still not sure what this means for you?
Bring your reports to a call with one of our doctors. Leave with a written summary and the right questions for your own doctor.
