Bioaerosols: managing the hidden risks

A new technical specification on measuring moulds in ambient air could have a huge impact on organic waste treatment solutions. Adam Read and Jason Southgate explain why

Bioaerosol is a broad term for airborne particles of biological origin. Depending on the emission source, they vary widely in composition. Typically, bioaerosols consists of micro-organisms and their constituent elements such as bacteria, fungi, spores, moulds, pollens and endotoxins.

They are associated with the release of organic matter into the ambient air and with it any micro-organisms that may be present. In nature, bioaerosols are abundant in the environment and ambient concentrations vary with both the weather and the season.

Industry and the media’s recent interest in bioaerosols is a direct response to a growing concern about the release of bioaerosols from different anthropogenic sources such as agriculture, construction and waste treatment facilities, which has increased well above natural background levels in recent years.

The real threat that is posed by bioaerosols is the increased risk of health-related problems such as respiratory diseases, acute toxic effects, allergies and cancer. This is due to the ability of the micro-organisms and their associated products to be inhaled deep into the respiratory tract and to penetrate into the body. The risk of developing a range of respiratory symptoms increases with prolonged exposure (or in some cases short-term exposure) to elevated levels of bioaerosols.

Given the Government’s support for anaerobic digestion and an upward trend in councils collecting food and garden wastes in one form or another, the potential risks from bioaerosols are likely to grow. The danger is that this could undermine the UK’s strategy for using AD as a waste treatment provider and renewable energy producer, and hinder any plans for organic waste collection, storage and treatment.

Planning and permitting bodies such as councils and the Environment Agency (EA) now require risk assessments and regularly monitor bioaerosol emissions on sites that fall under the “potential to cause local health concern to the workers and surrounding public” category of facilities/sites. This situation needs careful attention and management.

The British Standards Institute (BSI) recognises the increasing levels of concern and interest in bioaerosols and has released a technical specification (CEN/TS 16115-1:2011) on the measurement of moulds in ambient air to identify, quantify and characterise bioaerosol pollution in ambient air resulting from emissions from different sources.

The BSI document is just a technical specification rather than a full British or European standard. But, this would not prevent the specification from being a legal requirement in UK permits if the permit issuer (either the EA or a local authority) was sufficiently concerned that the determinant posed a health/safety/environmental impact.

We expect further legislative developments on the immediate horizon which the UK waste industry will have to conform to. There is also the longer term potential that obtaining monitoring data as part of any annual reporting will also have to be achieved using accredited laboratories.

The waste sector will need to monitor this situation in the next six-to-nine months because it could mean an increase in the costs of monitoring and reporting. A worst case scenario could see sites closing and applications refused.

All those involved in organic waste collection and treatment would be advised to look at their operations, handling and emission controls and seek help from specialist consultants.

The study of bioaerosols, their pathways and associated risks requires expertise in air quality and wastes management practices to ensure cost-effective solutions.

The BSI documents have already heightened interest in the issues of bioaerosols.

We expect it will be an area of significant research and investigation over the coming year.

Dr Adam Read is global practice director and Jason Southgate is a leading bioaerosols consultant at AEA

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