HHSEG Topic Talk - PowerPoint Presentation

Slide1

HHSEG Topic Talk 28 October 2015Workplace exposure to airborne dust – health effects & risk quantification

Gully Howard Technical, PortsmouthSlide2

In the UK there are ~13,000 deaths per year due to exposure to airborne hazardous substances at work. Thousands of different chemical agents can potentially cause detrimental health effects in a wide range of different occupations. These airborne hazardous substances can be classified as either gases, vapours,

fibres, mists, fumes or dust.

Airborne hazardous substancesSlide3

Key Health Factors of DustsToxic effectWhat is the toxicology of the material and the respective target organ?Particle Size

Where does it deposit? – upper respiratory tract or is it capable of reaching the alveoli in the deep lung?Inhalable dust

(<100 microns) is the term given to all the dust capable of being inhaled through the nose and mouth.

Respirable

dust

(<10 microns) is the dust small enough to reach the gas exchange region of the deep lung.Slide4

Silica – worker exposure occurs in many industries affected e.g. mining, construction, ceramics

RCS – Silicosis (fibrosis of lung) can lead to lung cancer

Examples of hazardous dustsSlide5

Wood dust exposure occurs in the construction industry particularly in woodworking workshops

rhinitis, nose bleeds, asthma, nasal cancer

Examples of hazardous dustsSlide6

Diesel Particle Matter (DPM) some workers can potentially receive high exposures to DPM

IARC designated human carcinogen, EC, OC, TC

Examples of hazardous dustsSlide7

The COSHH Regulations provides guideline exposure levels for ‘non-hazardous dusts’ of 10 mg.m-3 inhalable dust and 4 mg.m-3 respirable dust.These levels for ‘non Hazardous’ dusts are

considered too high bymany (e.g. IOM suggest

controlling to 5 and 1 and

TUC 2.5 and 1 mg.m-3.)

‘Non-hazardous’ dustsSlide8

Breathing Zone

Personal samples MUST be taken in the Breathing Zone

300mm Hemisphere around the nose and mouth

Source :Airmet Scientific – reproduced with permissionSlide9

Sampling PumpsSmall battery powered pumps that can be worn by a person on a waist belt.Most particulate sampling is carried out at flow rate of either 2.0 or 2.2

litre/min.Slide10

IOM Sampling HeadGold standard sampling head for measuring inhalable dust fraction

All

collected dust measured

(filter

is weighed with the

cassette)

Easily handled

25 mm filter

2.0 litres/min (± 0.1)

IOM sampler

IOM cassette

Transport clip

Front Cassette Filter Support O ring Body

cover front grid

Source :Airmet Scientific-reproduced with permissionSlide11

Cyclone Sampling HeadRespirable dust

25/37 mm filter

2.2 litres/min (± 0.1)

Pump attached at top

Inlet points down

Source: HSE – reproduced with permissionSlide12

FiltersWide range of filter types including:

Glass

fibre

filters

Good particulate retention, collects at surface and within filter, best for gravimetric analysis

Mixed cellulose ester (MCE)

Weight easily affected by humidity changes

Easily dissolved for analysis (metals)

Particulates collected on surface only (transport)Slide13

Sample Train for Inhalable DustPumpConnecting tubeIOM sampling head

SAMPLER

CONNECTING

TUBE

PUMP

Source :Airmet Scientific – reproduced with permissionSlide14

Sampler worn by a workerSource :University of Wollongong

Pump usually placed on belt, in pocket or in suitable harness

Sample head in breathing zone

Calibrate flow rate at start

- note start time

Check flow rate during sampling

Check flow rate at end - note stop timeSlide15

Calibration of sampling system Connect from pump to sampling head Connect from sampling head to calibrator

Adjust flow to required flow rate

Source :Airmet Scientific – reproduced with permissionSlide16

Dust direct reading InstrumentsMost dust monitors are based on light scattering techniquesBeam of light shone through contaminated air. Light scattered by the dust is detected and is a measure of particulate concentrationSlide17

Deleading butt

Vacuuming butt and target area

Break period

Vacuuming and mopping rest of range

Cleaning surfaces in firing area with wipe cloth

Determining

pattern of exposure

Results

from a

direct-reading

dust instrument mounted on cleaner

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Observations and investigation‘Art of occupational hygiene’Determining exposure period - required for calculating time weighted average (TWA)Assessment of controls in place - this is not an optional extra – it is the law (Principles of good practice, Schedule 2A, COSHH Regs

)General feel of the workplace (i.e. culture) Slide19

Choosing a LabLab working to a Quality System (ISO 17025).Analytical methods are UKAS accredited.Take part in HSL’s Workplace Analysis Scheme for Proficiency

(WASP) for metals, BTEX, RCS etc and can show for the last 3 rounds that they are consistently close to the ‘true value’.Slide20

Occupational exposure limitsTime weight exposure (over 8 hrs or 15 mins) and compare with long or short term OELs.Legal limits in UK

WELs (EH40)

Other European country’s OELs –

IFA GESTIS

website

US ACGIH

TLVs Slide21

ReportingMakes a record (by law it has to be kept for 40 years) – procedures need to be in place to ensure such records are maintained. Report has to work for now i.e. be

concise and clear and easily understood. But also be

future proof

– i.e. contain details on QA so it stands up in court in the future.

Must provide appropriate control advice if exposures are high – i.e.

what needs to done to protect the health of workers. Slide22

Any questions? Paul HumphreyChartered Occupational Hygienist

Paul.Humphrey@ghtechnical.com

Mob. 07944 629544

www.ghtechnical.com