Fresh air requirements for human comfort. Indoor air quality. Over the last few years considerable research has been conducted both here and in the USA to determine what pollutants exist in the ambient atmosphere and within buildings. These studies have principally looked at the prevalence of volatile organic compounds, pesticides, carbon monoxide and particulates.

Fresh air requirements for human comfort

Whilst we are all aware of reports of increased numbers of persons suffering, for example, from asthma, it is extremely difficult to correlate these with an increase in particular pollutants. A number of scientists and engineers have concluded that most people are likely to have the greatest contact with potentially toxic pollutants not outside but within buildings.

If we consider the gross amounts of one particular carcinogen i.e., benzene released into the atmosphere, the greater portion comes from automobile fuel (82%). The next highest sources are industry (14%) and domestic usage (3%). Cigarette smoke only contributes around 0.1% of the total. However, within the confines of a building, approximately 45% of the total exposure may come from smoking, 36% from inhaling petrol fumes and other common products and only 3% from industrial processes.

The corollary of these figures is to conclude that improved ventilation with an increase in fresh air levels and in association with improved filtration is a must. It could greatly improve the indoor air quality and hence reduce the risk of disease. Buildings could then claim to be more friendly to health. Similar conclusions can be reached for many other chemicals found at quite high concentrations inside buildings- even the “perc” (perchloroethylene) used by dry cleaners or the deodorisers used by ever increasing numbers of the population, have been reported to cause cancer at high concentrations.

If we add the potential risks due to carbon monoxide (from incomplete combustion in kitchens and elsewhere) and radon (a natural radioactive gas seeping from foundations and brickwork), one wonders why we should spend up to 90% of our lives within buildings. Is it just a coincidence that the author’s long living grandfathers (a fisherman and a farmer) spent most of their waking hours outdoors?

How to Replace a Ceiling Fan

The need for improved indoor air quality has persuaded many ventilation engineers that the way forward is to increase the amounts of outside fresh air circulated within buildings. But if that outside air is far from fresh there is a definite problem. It’s more than a possibility that I can open the windows and door of my Suffolk pub for a cooling breeze. Provided I am not too disturbed by the smell of silage or fertilisers, this is the most environmentally friendly way to ensure that l don’t breathe in Joe’s Old Holborn tobacco fumes or whatever.

It doesn’t require any fan power and doesn’t therefore increase the CO2 emissions from the nearby power station at Eye. In a big city building there are a different set of problems. The air outside is often worse than that inside. If it’s not the dust, it’s the petrol fumes.