Biological matter in an airborne state can transmit microorganisms via aerosol. These hazards are referred to as ‘bioaerosols’ and often pose a health risk for those working in agriculture, waste recycling, sewage treatment, composting and landfill sites.
Materials handled in these industries can be contaminated with harmful microorganisms. When contaminated material is processed in a way that releases particles into the air, the biological mater can be inhaled and cause ill health. They are made up of both live and non-living components, including fungi, mould spores, pollen, bacteria and can include viruses. When adding humidity and temperature into the mix it can activate growth of airborne microorganism particles.
Bioaerosol exposure can cause coughing, shortness of breath, itchy eyes, sickness, nausea, diarrhoea and fatigue. Workplace exposure to bioaerosols in the waste industry is associated with an increased risk of developing upper and lower respiratory symptoms.
In addition to inhalation risks, direct unprotected contact (without PPE worn) would increase potential infections and possible diseases.
A risk assessment should be completed to identify bioaerosol hazards on site and determine the required control measures. RPE may be required if workers come into contact with microorganisms transmitted by the airborne route.
HSE publication HSG53 provides guidance on choosing RPE for bioaerosols:
- Particulate filter-type RPE will usually remove microorganisms.
- Equipment with the highest efficiency filter possible, offering a UK Assigned Protection Factor (APF) of at least 20, should be selected.
An APF of 20 can be achieved by using:
- FFP3 disposable respirator
- Half mask with P3 filters
- Powered air purifying respirator (PAPR) device with TH2P filters
To further reduce exposure, a higher protection factor of 40 can be achieved by using:
- Full face mask with P3 filters
- PAPR device with TH3P filters
PAPR devices can offer greater suitability for some tasks. HSG53 advises that a PAPR with full facepiece or hood/blouse may be most suitable for cleaning cooling towers using high-pressure hoses, due to the work rate and wet conditions.
Tight-fitting RPE must be fit tested to ensure suitability for the wearer. Find out more about respirator fit testing.
For composting sites, a ‘risk zone’ approach can be applied to control exposure to bioaerosols. A study was conducted by taking bioaerosol measurements during compost handling and at fixed points up to 250 metres away from compost handling activities. The research defined red, amber, yellow and green zones relating to bioaerosol concentrations, helping to determine where on site RPE is required and what level of protection is appropriate.
RPE used for protection against bioaerosols must be maintained and disposed of correctly to ensure good hygiene and prevent further contamination. Used RPE should be treated as potentially contaminated and kept separate from other PPE.
Non-reusable equipment should be disposed of as contaminated waste. This includes:
- Disposable respirators
- Filters and pre-filters for reusable respirators
Reusable respirators can be cleaned and disinfected in accordance with the product’s user instruction leaflet. It is important to keep reusable RPE clean and avoid storing used filters to prevent microorganisms contaminating the equipment and creating a new exposure hazard. See HSG53 Appendix 6 for more information on selecting and maintaining RPE for bioaerosol hazards.
Additional control measures and equipment are often required to protect against other forms of exposure hazards. Protective clothing, faceshields and washing facilities can be necessary to control the risk of exposure from direct contact with microorganisms. A full risk assessment is needed to identify the hazards and appropriate control measures for a specific workplace.
The HSE website provides guidance for different industries and processes:
Email technical@jspsafety.com for assistance in selecting RPE for bioaerosols.