Is your ventilation system working properly?

Ventilation, the "V" in HVAC, is often ignored. We pay great attention to heating and air-conditioning systems - their operation is critical to comfort, and heating and cooling can constitute an important part of the building utility bill. This can encourage people to reduce ventilation as much as possible, because the outdoor air must reach the indoor temperature and humidity level, whether in hot or cold weather, this is an expensive suggestion.

But ventilation is crucial. Recycled indoor air can cause dangerous levels of pollution, damage the health of occupants and reduce productivity. According to the health building project of Harvard University, Americans spend 90% of their time indoors, so maintaining indoor air quality should be the primary task of occupational health and safety. The introduction of healthy fresh air can reduce several health hazards.

Let your architecture breathe

With each breath, we will exhale carbon dioxide into the room. In a crowded and poorly ventilated room, the Environmental Protection Agency reported that the content of carbon dioxide could reach five times that in the outdoor atmosphere.

A paper in Environmental Health Perspectives found that high carbon dioxide concentration significantly reduces workers' cognitive ability and their strategic decision-making ability. According to the Journal of Occupational Health and Safety, the common indoor carbon dioxide level can lead to headache and fatigue.

Ventilation is the only feasible way to reduce indoor CO2 level. The carbon dioxide content in the atmosphere is relatively low, so circulating fresh air indoors will dilute the carbon dioxide accumulated in the occupied space. In order to maintain a healthy balance, the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) has formulated a ventilation standard that requires buildings to introduce at least 15 cubic feet of fresh air per minute for each occupant.

Is your building sick?

According to EPA, poor ventilation is the main cause of "sick building syndrome", which is a series of symptoms caused by exposure to volatile organic compounds (VOCs), particulate matter and biological pollutants. Sick building syndrome can cause a variety of symptoms, from mild headache and dry cough to chest tightness, fever and muscle soreness.

Your building does not have to be an industrial facility that produces VOCs. These compounds, including toxic gases such as formaldehyde, will accumulate steadily in almost any workplace. They emit trace amounts from daily necessities, including copiers, interior decoration, carpets, artificial wood, adhesives and cleaning products.

Emissions from indoor combustion will also accumulate in poorly ventilated rooms. The Rocky Mountain Institute reported that burning natural gas on a stove or a non-ventilated fireplace would introduce toxic nitrogen dioxide and carbon monoxide into the room.

In order to prevent the accumulation of toxic pollutants, ASHRAE requires that every 100 square feet of building area be ventilated with at least 15 cubic feet of fresh air per minute. For enterprises that use more volatile organic compounds such as car repair shops and beauty salons, the ventilation requirements may be 10 times higher.

The best disinfectant

Recycled air can also cause dangerous accumulation of infectious microorganisms and toxic molds. Outside, natural circulation will dilute pathogens, and sunlight will degrade virus particles, thus greatly reducing the risk of infection. The Center for Disease Control and Prevention recommends that enterprises open the fresh air baffle as much as possible, and consider opening the window to inhale fresh air, so as to reduce the spread of COVID-19. According to a report of the World Health Organization, inadequate ventilation will also accelerate the spread of other airborne diseases, such as influenza, cold and chickenpox.

Exceeding the minimum value

The energy cost of raising ventilation to above the minimum standard can be offset by increasing productivity and reducing absenteeism. A study published in the journal Indoor Air found that when the ventilation rate of the building doubled from 25 cubic feet per minute (cfm) per household to 50 cubic feet per hour, the short-term absence rate decreased by 35%.

Beware of adverse factors

Finally, please remember that increasing ventilation has disadvantages. Berkeley National Laboratory warned that air inlets near pollution sources, such as busy highways, would bring ozone and other particulate pollutants into buildings. The humid outdoor air will also create conditions for the growth of mold and dust mites, which can cause asthma in buildings. Make sure that your HVAC system filters and regulates external air to eliminate these hazards.

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