Glossary

Plain-language definitions of the terms used across this site. Species pages link here.

Health effects

Sensitizer

A substance that can teach your immune system to react to it. The first exposures cause no symptoms, but once you are sensitized, even small amounts can trigger a reaction.¹² See also respiratory sensitizer and skin sensitizer.

Respiratory sensitizer

A sensitizer that causes allergic reactions in the nose and airways, from a runny nose to asthma.¹ UK limits mark these with “Sen”.¹

Skin sensitizer

A sensitizer that causes allergic contact dermatitis when it touches the skin.³

Irritant

A substance that inflames the skin, eyes, nose or throat directly, without involving an allergy. Repeated contact with even mild irritants can cause problems.³

Occupational asthma

Asthma caused by something breathed in at work. Symptoms include wheeze, chest tightness, breathlessness and cough, and often improve on days away from work.² It can be lifelong.²

Rhinitis

Inflammation inside the nose: runny, itchy or blocked nose and sneezing. With wood dust it can be an early allergic sign that comes before asthma.²

Dermatitis

Inflammation of the skin, usually red, dry and itchy, sometimes with flaking, cracking or blisters.³

Irritant contact dermatitis

Dermatitis caused by direct damage to the skin, for example from dust rubbing on sweaty skin or frequent washing. It usually settles once the skin heals.³

Allergic contact dermatitis

Dermatitis caused by an allergy to something that touches the skin. It can take weeks to years to develop, and once it has, tiny amounts set it off.³

Urticaria

Hives: raised, itchy welts with redness that appear soon after contact and fade within hours.³

Hypersensitivity pneumonitis

An allergic inflammation deep in the lungs, also called extrinsic allergic alveolitis. It causes a flu-like illness with breathlessness and is rare with wood dust.⁴⁵

Photosensitization

A reaction where skin becomes more sensitive to sunlight after contact with a substance. HSE notes it for a few woods.⁴

IARC Group 1

The International Agency for Research on Cancer’s highest category, “carcinogenic to humans”, used when there is sufficient evidence in people. Wood dust has been in Group 1 since 1995.⁶⁷

ACGIH carcinogen classes

The American Conference of Governmental Industrial Hygienists ranks substances A1 (confirmed human carcinogen) to A4. It lists oak and beech dust as A1, birch, mahogany, teak and walnut as A2 (suspected), and other wood dusts as A4.⁸

Sinonasal adenocarcinoma

A cancer of the lining of the nose and sinuses. It is the cancer most strongly linked to long-term wood dust exposure.⁶

Nasopharynx

The space at the back of the nose, above the throat. IARC links wood dust to cancer here as well as in the nose and sinuses.⁷

Dust and exposure

Inhalable dust

The part of airborne dust that enters your nose and mouth when you breathe.¹ Most wood dust limits are set for this fraction.⁹⁸

Respirable dust

The finer part of airborne dust that reaches the gas-exchange region deep in the lungs.¹

Total dust

The dust measure used in OSHA’s general particulate limit, which is the federal limit that applies to wood dust in the US.⁸

Time-weighted average

The average concentration of a substance in air over a set period, usually an 8-hour shift. Most exposure limits are written this way.¹

Short-term exposure limit

A limit averaged over 15 minutes, meant to prevent effects from short, high exposures.¹

Exposure limit

The maximum average amount of a substance in workplace air. Names vary: OSHA and Cal/OSHA use PEL (permissible exposure limit), NIOSH uses REL (recommended exposure limit), ACGIH uses TLV (threshold limit value), and the UK uses WEL (workplace exposure limit).⁸¹⁰¹ See Limits.

As low as reasonably practicable

A UK legal principle: for substances that cause cancer or asthma, exposure must be cut as far as is reasonably practicable, not just to the limit.¹

Controls and equipment

Hierarchy of controls

The ranking of protective measures from most to least effective: elimination, substitution, engineering controls, administrative controls, and personal protective equipment.¹¹

Local exhaust ventilation

Extraction that captures dust at the tool where it is made, using hoods, ducts, a fan and a filter. Often shortened to LEV.¹²

Dust class M

A vacuum rating for medium-hazard dust. HSE recommends at least class M for cleaning up wood dust.¹³

HEPA filter

A high-efficiency particulate air filter, designed to catch very fine particles. HSE recommends HEPA-type vacuums for routine dust cleaning.¹⁴

Filtering facepiece respirator

A disposable respirator where the mask itself is the filter, such as an N95 or FFP3. It filters particles, not gases or vapors.¹⁵

N95

A US filter class: N means not oil resistant and 95 means it caught at least 95% of test particles.¹⁵

P100

A US filter class: P means strongly oil resistant and 100 means it caught at least 99.97% of test particles.¹⁵

FFP3

A European class of disposable filtering facepiece respirator. HSE says disposables suitable for wood dust are often described as FFP3.¹²

PAPR

Powered air-purifying respirator: a battery-powered blower pushes filtered air into a mask, hood or helmet. Loose-fitting types work with facial hair.¹⁶

Assigned protection factor

A number showing how much a type of respirator is expected to reduce exposure when worn properly. A factor of 10 means about a tenth of the dust gets through.¹⁷

Fit test

A test that checks a tight-fitting respirator seals on your face, either by taste or smell (qualitative) or with an instrument (quantitative).¹⁸

User seal check

A quick check each time you put on a tight-fitting respirator: breathe in and out and feel for leaks. It does not replace a fit test.¹⁵

Fire

Combustible dust

Dust fine enough to burn rapidly or explode when spread in the air. Wood dust is one.¹⁴

Secondary explosion

A second, often larger explosion caused when a first blast shakes settled dust into the air and ignites it.¹⁴

Spontaneous combustion

When something catches fire from heat it makes itself, with no flame or spark. Rags soaked in drying oil finishes can do this.¹⁹

Evidence

Evidence level

Dust Almanac’s label for how strong the evidence is behind each hazard: confirmed in clinical testing, listed by an agency, reported, or general. See Methodology.

Specific inhalation challenge

A supervised clinical test in which a person breathes a small, controlled amount of a suspected dust to see if it triggers asthma. A positive result gives our level 1 rating.

Patch test

A skin test where small amounts of suspected allergens are taped to the skin for a few days to check for allergic contact dermatitis. A positive result gives our level 1 rating.

Specific IgE

Antibodies to a particular substance, measured in a blood test. Finding them shows the immune system has become sensitized to it.

Last reviewed 2026-11-07.