The health impact of the diesel scandal

Giuseppe Borgese, chairman of the Building Engineering Services Association’s Indoor Air Quality Action Group, considers the health imapact of the diesel scandal on building occupants.

Poor air quality in urban areas is held responsible for 29,000 premature deaths in the UK every year (360,000 across the EU), which is more than obesity and alcohol combined, according to Public Health England. New studies carried out by Kings College, London have linked nitrogen dioxide (NO2), which is often caused by petrol and diesel emissions, to higher rates of mortality, lung cancer and heart failure. The World Health Organisation (WHO) has declared diesel particulates as a Class 1 carcinogen.

The recent scandal over falsified test data from diesel car manufacturers has put this issue into stark context and, although the nature of the problem is now out in the open, it will take many years to remove the effects of these emissions from the air in our cities.

In central London the concentration of diesel and nitrogen dioxide (NO2) is about three times the level recommended by the WHO. This figure was only made public following a challenge from the Campaign for Clean Air. Benchmark estimates from the Harvard Six Cities survey indicate that central London suffers a 20 per cent increase in mortality rates as a result of mainly traffic particle air pollution.

Epidemic
The building engineering industry has been pointing out for some time that this growing outdoor air pollution epidemic also has a direct impact on people inside buildings – particularly in schools, hospitals and offices. Many facilities managers and building managers have not taken the necessary steps to protect occupants from the effect of outdoor air pollutants entering their buildings.

Poorly maintained ventilation systems; clogged or missing filters; dirty ductwork and ageing air conditioning systems are all contributing to a huge health and well‑being problem. If the government has lost control of the outdoor air; then we must take urgent measures to protect building occupants and make sure our buildings are a haven from the pollution outside.

However, this task has been made more difficult over the last two decades by the drive to improve the energy efficiency of buildings, which has involved making them more airtight. Sealing up buildings puts greater pressure on ventilation systems to dilute rising levels of CO2 and replenish oxygen while simultaneously trying to prevent the rising number of harmful external pollutants from finding their way inside.

Many airborne particles are precisely the right size for inhalation into lungs. The human body has no way of removing these invaders so they go on to cause damage and disease to vital organs. The Harvard survey showed how exposure to airborne particles below 10 microns in size posed a serious health risk. Those beneath 2.5 microns (PM2.5) are referred to as ‘fine’ particles and are particularly dangerous because they settle deep in the lungs.

The Healthvent EU research project reported last year that almost two thirds of the burden of disease traced back to poor indoor air quality (IAQ) was from pollutants coming into the building. If you live on a busy arterial road in London you are continually exposed to two or three times more harmful inhalable particulates than the WHO warning level. Whether you are inside or outside a building, you are under siege; and let’s not forget that we spend 90 per cent of our time indoors.

For good health and productivity the air where you live or work needs to be about 20-24degrees Celcius with a relative humidity (RH) of about 40-60 per cent. The ventilation system needs to dilute CO2 levels and replace oxygen – it’s a very fine balance, especially when most establishments are now heavily focused on reducing energy use.

Air tight building envelopes can be a good way of keeping out external pollutants, but they often lead to occupants opening windows, which is not such a good idea unless you know the level of pollutants you are letting in. Ensuring the ventilation system works well is a better solution. Measurements have shown that a well-sealed building envelope and effective filtration of incoming supply air can reduce particle penetration by 78 per cent. There has been a growing interest in airtightness testing to help improve energy efficiency perspective, but that process can also be used to measure IAQ.

Hygiene
Every planned maintenance regime should include a check on air handling unit performance as well as a ductwork hygiene inspection and remedial cleaning. The new BS EN 15780 standard provides recommended inspection time periods for air systems and the revised Guide to Good Practice for Ventilation System Hygiene (TR/19) from the Building Engineering Services Association (the BESA) is adopting this guidance, which can be very helpful to FMs.

The Building Services Research and Information Association (BSRIA) has reported a very high success rate for building airtightness tests with 89 per cent of 10,000 tests meeting energy efficiency standards set out in Part L of the Building Regulations. However, it also recorded repeated problems with mechanical ventilation systems charged with ensuring these airtight buildings also benefit from adequate ventilation rates. It suggested that most of the problems were as a result of installation faults explained by poor training and lack of experience. This is adding to IAQ issues; rising condensation and damp problems; and the consequent impact on the respiratory health of occupants.

Air filtration quality efficiency also has to be addressed. Standard G3 filters will not necessarily deliver the level of clean air quality required; the only recommended solution available at the moment that also provides improvements at low energy are F7 filters. In areas with high NO2 levels gas filtration should be considered. However, many good filtration systems are compromised if the filters are inserted in side withdrawal mounting rails, which means the air can bypass the filter and travel around it.

Second stage air filters are designed to remove smaller particles and they must be mounted in properly engineered front withdrawal mountings to ensure they can be fully sealed and air does not bypass them, thus defeating the object of fitting them in the first place. Low energy air purifiers can also be used as a room‑by‑room solution. Many of the remedial measures needed to improve IAQ are not expensive. Cleaning intake grilles, for example, is very straightforward and will payback in a matter of hours because of the immediate running cost and health benefits. Servicing and upgrading ventilation fans will also ensure the system operates more effectively as well as reducing energy costs.

However, the first step is to set up a process for measuring indoor pollutants.

It is still rare for facilities managers to even consider IAQ as a threat – they tend to be more focused on maintaining comfortable temperatures and adequate lighting levels in response to occupant complaints; or on looking for ways to reduce energy consumption.

They now face a longer term and increasingly serious IAQ problem that can directly affect the health and productivity of building occupants. Recognising the threat and taking action will become increasingly valuable as the situation outside continues to deteriorate.

The Building Engineering Services Association is the UK’s leading trade organisation for building engineering services contractors - representing the interests of firms active in the design, installation, commissioning, maintenance, control and management of engineering systems and services in buildings.

Further Information
www.thebesa.com