In plain terms, condensation occurs when excess moisture, or humidity in the air reaches a saturation level at a surface such that moisture will begin to appear on that surface. This is also referred to as dewpoint. Temperature is also a key element of this. As an example, when hot damp air meets a cold surface such as when a cold can of soda is taken out of a refrigerator and placed on a benchtop, the cold contents of the can and the room-temperature air will interact to cause condensation to form on the outside of the soda can.
Within the indoor environment, key factors that affect condensation can include the outside temperature, inside temperature, surface temperature, and both indoor and outdoor humidity levels, as well as the nature of the materials comprising building and contents, and even occupant behaviour and indoor environmental controls can influence condensation.
Obvious fungal risks exist within homes that have experienced a water intrusion event. Where a water intrusion event has not occurred, excess moisture or humidity can create the necessary conditions for fungal growth.
21st Century building principles have included a general tightening of the building envelope, towards more airtightness. The move toward energy efficiency has contributed to less natural airflow environments and more artificially heated and cooled environments. Artificially controlled environments may be accompanied by increases in localised moisture, such as through condensation via uneven distribution of heat to surfaces, which may lead to biological issues such as fungal and bacteria growth within the built environment. Other building factors that can lead to unevenly heated surfaces include shading effects, contrast of sun facing and non-sun-facing walls, thermal bridges operating through otherwise insulated walls and ceilings, and the like.
Our lifestyles can also be contributing factors to poor indoor air quality. Whilst most of us now spend approximately 90% of our time indoors, we also spend less time with our windows and doors open to create natural cross ventilation to our homes. Another lifestyle issue that often contributes to dampness is not allowing exhaust fans enough time to run for after showering or cooking, as the steam that is created causes condensation directly. Carpets and rugs as flooring choices are problematic for indoor air quality in two ways: they hold nutrients that mould and fungi can consume in order to grow, and they also act as a store for Volatile Organic Compounds (VOCs) that can be biologically or non-biologically derived. Carpets and rugs should be regularly cleaned to an as-new state of cleanliness, and only used at all if thoroughly dry. Regular vacuuming of carpets and rugs or shaking them outdoors are also optimal practices. Clothes transport VOCs indoors and can concentrate VOCs in wardrobes, so frequent clothes washing is recommended as for rugs. Even unused clothing can accumulate VOCs, so these too benefit from washing.
VOCS range widely in harmfulness, from relatively inocuous to very harmful. If concerned about potential presence of Microbial VOCs, one clear avenue to follow is to seek a specific airborne mycotoxin report elsewhere. Mycotoxins are toxins produced by moulds. An IAQ Level report from IAQ Analytics is not a report of airborne mycotoxins. Rather, it concerns airborne spore chains, through analysis of the coarse fraction of airborne particulates. An ATP Surface Cleanliness report from IAQ Analytics is not a report of surface mycotoxins, but rather assesses biological contamination broadly, derived from cellular origins.
Airborne particulate matter can enter our homes in many ways, including on our clothing, or furnishings. Particulate matter, entering to the indoors from the outdoors, is made up of a huge variety of substances including dust, pollens, fungal spores, ash, smoke, dust mites, and many other biological, fungal and viral particles. Some of these can multiply in certain conditions and become irritants and allergens that affect susceptible persons. Particulate matter is also made up of "volatile" (meaning airborne) compounds, that attach to these dust particles. A compound can be a chemical of any sort, and typically indoors these are derived from fittings such as carpets, flooring, furniture, paints, wood and wood-derived materials, synthetic materials etc but can also include microbially derived compounds and household cleaning/treatment products, and are not limited to the categories of sources listed.
IAQ Level signifies a particle-count level achieved through a single sampling per room where the sample duration corresponds to industry benchmarks. A current calibration certificate is suggested for the meter used, and accordingly the IAQ level is accepted throughout the industry. The IAQ Level report references selected sections of applicable Published Standards, and draws much less on Empirical Principles. See References section.
PSC is reported against references listed at the conclusion of this report and meets both the required number of samples within a given area and required length of time sampled, so is in that sense consistent with the applicable Published Standards. See References section.
Airborne particle count data submitted to IAQ analytics is taken using a 6 channel particle counter. Currently only data from selected handheld counters is accepted for assessment by IAQ Analytics. The accepted meters are listed on the IAQ Analytics website and IAQ Analytics app repositories.