NEBOSH CC Dust & Noise in Construction 2

Question 1

What is the maximum Workplace Exposure Limit (WEL) for wood dust in the UK under EH40?

Accepted Answer

3 mg/m³ (8-hour TWA) for hardwood dust, 5 mg/m³ for softwood dust

Answer

Under EH40, the WEL for hardwood dust (and mixtures containing hardwood) is 3 mg/m³ as an 8-hour TWA. For softwood dust, the WEL is 5 mg/m³ as an 8-hour TWA. Hardwood dust is a Group 1 carcinogen.

Question 2

Why is hardwood dust considered more hazardous than softwood dust?

Accepted Answer

Hardwood dust is classified as a known human carcinogen (Group 1) linked to sinonasal cancer

Answer

Hardwood dust (including oak and beech) is classified as a Group 1 known human carcinogen by the International Agency for Research on Cancer (IARC). Long-term exposure is associated with sinonasal cancer (cancer of the nose and sinuses).

Question 3

What does the term 'inhalable dust' mean in occupational hygiene?

Accepted Answer

Dust particles small enough to be inhaled through the nose and mouth, settling in the upper airways

Answer

Inhalable dust refers to the fraction of airborne particles that can be inhaled through the nose and mouth and deposited in the upper respiratory tract. It includes particles up to approximately 100 micrometres in aerodynamic diameter.

Question 4

What is 'respirable dust' in occupational hygiene?

Accepted Answer

The fraction of airborne dust small enough to penetrate to the alveoli of the lungs

Answer

Respirable dust is the fraction of inhaled particles that is small enough (typically below 10 micrometres aerodynamic diameter) to penetrate beyond the larynx and reach the alveoli of the lungs, where gas exchange occurs.

Question 5

What is the lower action value (LAV) for noise exposure under the Control of Noise at Work Regulations 2005?

Accepted Answer

80 dB(A) daily or weekly average exposure

Answer

The lower exposure action value (LAV) for noise is 80 dB(A) as a daily or weekly average. At this level, employers must make hearing protection available and provide workers with information about the risks. Action is required but hearing protection is not mandatory.

NEBOSH Construction Certificate Practice Test

NEBOSH Construction Certificate Practice Test

NEBOSH CC Dust & Noise in Construction 2