Indoor Air Quality: We stir up millions of bacteria when we enter a room

New Study: Yale Researchers say findings might help efforts to improve indoor air quality.

Indoor Air Quality - bacteriaA person’s mere presence in a room can add 37 million bacteria to the air every hour — material largely left behind by previous occupants and stirred up from the floor — according to new research by Yale University engineers.

We live in this microbial soup, and a big ingredient is our own microorganisms

said Jordan Peccia, associate professor of environmental engineering at Yale and the principal investigator of a study recently published online in the journal Indoor Air.

Mostly people are re-suspending what’s been deposited before. The floor dust turns out to be the major source of the bacteria that we breathe.

Many previous studies have surveyed the variety of germs present in everyday spaces. But this is the first study that quantifies how much a lone human presence affects the level of indoor biological aerosols.

The research team measured and analysed biological particles in a single, ground-floor university classroom over a period of eight days — four days when the room was periodically occupied, and four days when the room was continuously vacant. At all times the windows and doors were kept closed. The HVAC system was operated at normal levels. Researchers sorted the particles by size.

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HVAC plant cleanliness and how indoor air quality is affected

The original purpose for having air filters in HVAC plant was to protect the plant and its operating efficiency. It is only in the last few decades that the priority of health protection of people in buildings has taken over as the primary purpose for these air filters.

Changing HVAC Air filters for IAQ

The current condition and cleanliness of HVAC plant needs to be regularly determined as it can have a significant effect on the Indoor Air Quality of the building. Also needed is a visual inspection of the air filters to see if they are well installed, fit for purpose and in good condition.

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Air pollution can increase risk of heart attack

Analysis now shows that heart attacks are more common at high levels of every main pollutant except ozone. Is the problem of air pollution being taken seriously?

IAQ Air Pollution

Studies have shown that an increase in air pollution has been linked to a decrease in lung function, according to The World Health Organisation (WHO) air pollution causes 2million premature deaths annually.

Researchers from the Paris Cardiovascular Research Centre, led by Harzrije Mustafic, have found that heart attacks were slightly more common at high level of every main pollutant except ozone.

Reporting in the Journal of the American Medical Association, they looked at 34 studies, comparing the risk of suffering a heart attack or myocardial infarction (interruption of blood supply to the area) at various levels of inhaling industrial and traffic-related pollutants.

The reports included anywhere from 400 to 300,000 people, with heart attacks that were confirmed in hospital records and disease or death registries.

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