Indoor air pollution can arise from construction materials used in the building, the furnishings, fixtures and equipment in the building, the land buildings are on or from materials used at work (wood dust, cement dust, glutaraldehyde fumes) or created during the production process (welding gases, oil mists, solvent fumes, ozone).

How does indoor air-pollution affect the body?

The effects of indoor air pollution vary. The skin, eyes, nose, throat and lungs can be affected, depending on the pollutant. Flu-like symptoms may also be experienced together with blocked or runny noses; occasionally nausea may accompany these symptoms. In the long term, when people are dosed up with polluted air daily, the above symptoms become more serious and permanent injury can result.

The Health and Safety Executive (HSE) estimates that each year there are over 1000 new cases of asthma caused by exposures at work. These figures are based on returns from a number of health studies being conducted during the 1990's. It is believed by the HSE that the true figure is probably at least three times this. Additionally, the HSE reports that 70,000 people in the UK believe that they have asthma caused, or made worse, by substances breathed in at work.

Health risks from air pollution are not simply limited to bronchial problems. Chemical dusts and fumes find their way into the body via exposed skin surfaces as well as the lungs, causing diseases which vary from permanent painful and irritating skin conditions, to central nervous system damage, brain damage, liver damage, cancer, damage to eyes and straightforward poisoning.

Lifelong ill-health can result from being sensitised to naturally occurring substances such as ozone; this gas accumulates in workshops or offices where there is equipment that uses electrostatic discharges (electric arc welding in workshops and, in offices, photocopier and laser printer use). There is the possibility of developing a condition called Multiple Chemical Sensitivity (MCS) which causes the body to react badly to a range of chemical exposures at very low doses.

The workplace

Manufacturing processes and production areas are neither the only or most typical sites of air pollution. A group of secretaries and their manager were seriously and permanently affected after breathing formaldehyde fumes and wood dust because their employer had a defective ventilation system that simply transferred the dust and fumes from the workshop to their office. In another workplace, workers suffered low level carbon monoxide poisoning (splitting headaches) when car exhaust fumes from the car park were sucked into the ventilation air-intake and blown throughout the building.

The law

"Effective and suitable provision shall be made to ensure that every enclosed workspace is ventilated by a sufficient quantity of fresh or purified air". (Regulation 6 of the Management of Health, Safety And Welfare Regulations 1992)

Employers' legal duty arises under Section 2 of the Health and Safety at Work Act 1974 which requires them to do all they can to provide a safe system of work and a safe working environment. Employers may have to conduct a risk assessment either under Regulation 6 of the Control of Substances Hazardous to Health Regulations 1995, if the polluting substance(s) is used in the workplace or results from a manufacturing process; or under Regulation 3 of the Management of Health and Safety at Work Regulations 1992, which places a duty on the employer to make a risk assessment if the substance arises from some other source.

Ventilation.

Ventilation may be either dilution ventilation or exhaust ventilation. Dilution ventilation, at its worst ensures that the pollution is evenly distributed throughout the workplace, e.g. fans mixing up the air and moving air around within an airless workplace. Local exhaust ventilation (LEV) ensures pollution is removed at its point of generation.

If there is general exhaust ventilation the air in an office or factory is replaced with pure air; three complete changes of air per hour is the European standard deriving from the Guidelines for Ventilation Requirements in Buildings published in 1992 by the Commission of the European Communities. Further guidance on air flow rates is given by the HSE.

Rooms housing office machinery such as photocopiers or workshop machinery producing dust or fume or rest rooms where tobacco smoking is allowed, should have separate extract ventilation systems. Air inlets for the ventilation system should be sited to avoid introducing pollution from outside the building.

Controlling dust by cleaning

The most effective action is to remove the source of risk; this is done by identifying what is polluting the air (fumes, dusts, tobacco smoke, oil mist, etc.) and removing that source from the environment by elimination, encapsulation or by LEV. But keeping the workplace clean is an important control measure for dust hazards.

Inhalable dust: This is visible dust which is collected in the saliva and mucus in the mouth, throat and nose and either expelled from the body or ingested. Dust contaminated by toxins can find their way into the digestive tract and on into the blood stream and be distributed around the body and its organs.

Respirable dust: Is not visible to the eye nor to some optical microscopes. The dust by-passes the body's filters and enters the lungs and lodges in the gas exchange cells of the lung (alveoli). Toxins may be taken into the bloodstream this way too. Rory O'Neill, in his book "Asthma at Work", says that the current HSE exposure level of five milligrams of dust per cubic metre of air we breathe is more than twice the level that the nose, the bodies' front-line air filter, can cope with. Impurities can be expelled from the lungs by tiny "hairs" or cilia which waft impurities out of the lungs and up the windpipe towards the mouth. Often the impurities dissolve in the mucus and get into the bloodstream before they are expelled.

Normal vacuum cleaners, at best, only remove inhalable dust. Machines capable of removing respirable dust from the environment must be fitted with a high efficiency particulate air (HEPA) filter. Some domestic machines, such as the "Henry" or the "Dyson" can be equipped with such filters. Filters must be renewed regularly to remain effective.

Workplace action.

• Contact your trade union safety representative.
• Ask your employer to have air samples analysed
• Make a record all instances of illness in the accident book at work ensuring that they are recorded as work related.
• Alert your doctors to the relationship between workplace air pollution and any illness.
• Check the employer has arrangements for the effective planning, organisation, control, monitoring and review of preventative and protective measures.
• Inform members about taking civil action to pursue claims for damages from the employer. A civil action known as "the Walker case" set a precedent that where an employer re-exposes an employee to working practices that have already caused injury or illness the employer is automatically negligent.
• Use grievances procedures to expedite negotiation where managers block or are hesitant to deal with the issues. Take each complaint through to the final stage and register a "failure to agree" where a completely satisfactory result is not obtained.
• Provide HSE Inspectors with copies of inspection reports/surveys/illness and sickness records and other documentary evidence of your employer's breaches of law.

Further information.

• Asthma At Work - Causes, Effects And What To Do About Them. Rory O'Neill, Sheffield Occupational Health Project and TUC, ISBN 1-874751 02 1 (£6.00) Order from 01442 276 5695
• Sick Building Syndrome - Causes, Effects And Control. LHC Handbook ISBN 0-948974-06-0. Call 020-7794-5999 to purchase or obtain from your library; or order on this website The full text is online in our Resources Pages.
• Sick Building Syndrome - Concepts, Issues And Practice. Ed Jack Rostron ISBN 0-419-21530-1 (order from your local bookshop or library)
• Industrial Ventilation ISBN 0-936712-79-1 (order from your local bookshop or library)
• Controlling Asthma At Work HSE Books ISBN 0-717606-61-9. 01787 881165 to buy

Resources page