30 July 2019

How to Improve Air Quality in Your Home


Home upgrades often focus on improving appearance, and energy efficiency has also gained importance in recent years. However, indoor air quality (IAQ) is fundamental for human health, and the subject tends to receive less attention. The US Environmental Protection Agency has determined that indoor air is 2 to 5 times more polluted than outdoor air on average, and this applies even for urban areas.

Considering that humans spend around 90% of their time indoors in urban settings, controlling air quality is very important. There are three main ways to improve IAQ, and they can be used simultaneously to achieve the best results:

  • Eliminating or minimizing the sources of air pollution.
  • Designing an effective ventilation system, which ensures a constant supply of fresh air.
  • Removing pollutants directly from the air, by using filters or air purifiers.

There are many types of air pollutants, and some are notorious for their ability to remain undetected. Some are easy to identify due to their unpleasant smell, but others are odorless and colorless. There is a specific category of air pollutants called volatile organic compounds (VOC), and some even have pleasant aromas, causing the impression that they are harmless.

Which Substances Are Considered Air Pollutants?

Thousands of substances have been identified as air pollutants, but a few are the most relevant in building interiors. Depending on the reaction they cause, air pollutants can be described as irritants or allergens. To provide air quality for everyone, both types must be kept under control:

  • An irritant causes a negative reaction on anyone exposed to it. For example, ozone in the upper atmosphere blocks harmful radiation from space, but ground-level ozone is a potent lung irritant.
  • An allergen only affects susceptible individuals. Pollen, mold spores and animal dander are common examples of allergens.

Most air pollutants are not dangerous with short-term exposure, and most health conditions only develop when air quality has been ignored for long. However, some air pollutants are very dangerous even with brief exposure. Asthma patients are especially vulnerable, since pollutants can trigger flare-ups.

Carbon monoxide (CO) is extremely dangerous: the gas is released by combustion appliances that have poor ventilation, and it can poison humans at concentrations as low as one percent. The gas is colorless and odorless, which makes it even more dangerous, and CO sensors are normally required by law. Carbon monoxide should not be confused with carbon dioxide, which requires a much higher concentration to become dangerous.

Volatile organic compounds (VOC) and particulate matter (PM) are not as threatening as carbon monoxide with short-term exposure. However, they can lead to serious health issues in the long run.

  • VOCs are normally released by new construction materials, new furniture, cleaning products, artificial fragrances and cosmetics.
  • PM is normally released from combustion, just like carbon monoxide. PM in outdoor air may also form when other pollutants react chemically under sunlight.

Controlling Air Pollution with Smart Ventilation and Filtering

Large amounts of air pollutants are released in areas like kitchens, bathrooms and garages. All these areas should have extractor fans, to remove harmful substances before they spread to  other rooms. Air pollution sensors can be added to ventilation systems, activating the extractors automatically when harmful substances are detected.

Humidity is not considered an air pollutant, but organisms that affect air quality thrive in humid environments.

  • Mold is one of the best-known examples, and it can damage some construction materials in addition to degrading air quality.
  • Dust mites also reproduce faster with moisture, and they cause allergic reactions in many people.
  • Both mold and dust mites die off when relative humidity is reduced below 50%.

Plants are natural air filters, since they absorb many pollutants as part of their metabolic process. Indoor plants can improve air quality, but flowering plants should be avoided to prevent the release of pollen. Air filters and purifiers can also improve air quality, but ozone-based purifiers are not recommended. While they remove other substances, they defeat their own purpose by releasing ozone, a strong respiratory irritant.

Indoor air quality can be improved by minimizing the sources of pollutants, combined with effective ventilation and filtering. HVAC engineers can optimize the ventilation system design for a home, achieving both energy efficiency and air quality.

Michael Tobias is the founder and principal of Chicago Engineers, an Inc 5000 Fastest Growing Company in America. He leads a team of 30+ mechanical, electrical, plumbing, and fire protection engineers from the company headquarters in New York City; and has led over 1,000 projects in Chicago, New York, New Jersey, Pennsylvania, Connecticut, Florida, Maryland and California, as well as Singapore and Malaysia.

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