Indoor Air Quality

Indoor Air Quality Testing in Offices, Commercial Buildings and Homes

Indoor air quality testing is typically defined as testing the air in offices and commercial buildings. Air testing in industrial locations for metals, solvents, gasses and dusts is normally considered an occupational hygiene survey (see our separate web pages for these services). Baseline indoor air quality testing in an office or commercial building can be performed at relatively low cost.

One week of sampling is performed for carbon monoxide, carbon dioxide, temperature and humidity in an office or a commercial building. The one week period provides a representative sample of conditions in the workspace. The results are graphed and compared to current guidelines for each of these four parameters. A report that outlines how the tests were performed, graphs of all the results, interpretation of the results and recommendations based on the findings.

Indoor air quality can be cause be a number of different factors including:

  • Inadequate ventilation of fresh air
  • Outside contaminant entering building
  • Unusual source of indoor contaminant
  • Activities inside the building
  • Issues with the building construction / maintenance

IAQ investigations completed by the National Institute of Occupational Safety and Health (NIOSH), problems were found to result from:


This experience tells us that most indoor air quality situations can be evaluated using Phase I testing. Phase I testing includes the following:

  • Carbon dioxide monitoring to test for inadequate ventilation
  • Carbon monoxide monitoring
  • Temperature
  • Humidity

The most important parameter is the carbon dioxide level. People exhale carbon dioxide and give off a mixture of chemicals. The carbon dioxide level can be used as an index of the occupancy loading of an area relative to the amount of ventilation provided that air. Professional bodies have developed guidelines for acceptable levels of carbon dioxide in an office or commercial building.

In some cases, more elaborate tests such as mould testing and total volatile organic compound scans are used. However, Winnipeg Air Testing does not recommend these tests be performed until there is a clear indication that they are needed. Most indoor air quality conditions can be evaluated using relatively simple tests.

As conditions in a building may change from day to day due to variation in temperature, occupancy, wind direction, internal activities, etc., IAQ monitoring is normally conducted for a period of 3 – 5 days. Equipment specifically developed to test for this “package” of 4 monitoring criteria listed above provides excellent data about the conditions in a building. An example of a graph provided by the IAQ survey is shown below.

This graph is for carbon dioxide. The  first 5 peaks show the days of the week followed by a period of lower levels of carbon dioxide during the weekend. The peak at the right of the graph is from the Monday following the weekend. There are guidelines for allowable levels of carbon dioxide that relate to acceptable occupant satisfaction in an office environment. Similar graphs show the results for carbon monoxide temperature and humidity.

In most cases, testing for carbon monoxide, carbon dioxide, temperature and humidity provides enough information. In some cases, other forms of testing would be done depending on the nature of the concern. Testing for mould, allergens (dust mites, animals, etc.) and volatile organic compounds (VOCs) are also tests that can used in indoor air quality assessments.

Dust Levels / Dust Identification

A good general assessment of indoor air quality is a combination of the dust levels (particularly fine dust PM2.5 and PM10 dust which is strongly associated with health effects) and dust composition. The chart below shows the dust composition (or Dust ID) from a house. The test identified fibreglass fibers in both areas, ash-like soot from cooking in the kitchen and feather strands in the bedroom (from down pillow). The test is particularly useful in that it shows what is present and what is not present and quantifies the presence of each particle.

particle ID



Volatile Organic Compounds (VOC) Testing

An indoor environment can have a complex mixture of chemical from many common sources. Air sampling can be performed for VOCs that can identify the types of chemicals present in the environment, indicate their relative severity and identify the source of problem. The component of the results is a Total Volatile Organic Compound (TVOC) score that be compared to both guidelines in the literature as well as shown on a curve based on data from over 4,000 homes. At a glance, you see how your air compares to other homes.

The data goes on to give a breakdown of the VOCs by category of the types of chemicals and/or products in a home or office. It also rates each category using a normal to severe rating system. In the partial example below, the office environment has elevated VOCs arising from the use of odourants and fragrances.

Example of VOC Sampling Results

All indoor air quality testing is performed under a Certified Industrial Hygienists (CIH) with over 30 years of experience. The findings are provided in a comprehensive report that outlines the methodology used, the results of each sample, compares the results to existing guidelines and standards, and makes recommendations for improvement of the working environment.

For a free quotation please contact us.