Volatile Organic Compounds - TVOC

August 2021

1. Description

Volatile organic compounds- VOCs - or TVOCs - volatile organic compounds, are all those hydrocarbons present in a gaseous state at normal ambient temperature, or which are very volatile at that temperature. An organic compound that at 20°C has a vapor pressure of 0.01 kPa or more, or an equivalent volatility under the particular conditions of use - and a boiling point between 50 and 260°C - can be considered a VOC.

VOCs are frequently released from solvents, paints and other products commonly used in buildings. TVOCs are total organic compounds, the sum of all VOCs measured in indoor air.

2. Recommended levels

There are more than 120,000 chemical substances and more than 12 million published compounds. Of these, only a small part is studied from a medical perspective and there are limit values for only about 500 in the occupational/professional environment. In the residential environment, there are no specific regulations regarding volatile organic compound pollution - beyond recommendations.
For an overall assessment of total organic compounds, the total air concentration in ppb (parts per billion) or µg/m³ is measured for a ratio of alcohols, aldehydes, ketones, amines, siloxanes, aromatic and aliphatic hydrocarbons. Other compounds with a more critical health response, such as benzene, naphthalenes, cresols, or styrene, must be studied on a case-by-case basis.

According to standards:
The AGÖEF is the German Association for Ecological Research; an association of independent consulting and service companies involved in the measurement of indoor air pollution in built environments. Since 1993 they have been working on the development of reference values for chemical compounds, both in air and in dust samples, which are valid references for the work developed in this report.
The recommendation limits are classified as follows:

  • P50 - 50th percentile. Normal value. Not considered sufficient evidence for urgent action - TVOC less than 360 µg/m³.
  • P90 - 90th percentile. Attention value. Emitting source present - TVOC greater than 1572 µg/m³.
  • Guidance values - Guideline values - Equivalent to derived toxicological risk values - TVOC equal to 1000 µg/m³

The indicative values in the measurement standard SBM2015 refer to total volatile organic compounds, which are recommended as precautionary values for rest areas:

The limits established in Spain for exposures are listed according to individual compounds in the Occupational Exposure Limits for Chemical Agents in Spain, updated every year.
There is no reference value for indoor exposure in dwellings, nor for total organic compounds.

3. My inBiot Ranks

The reference values in My inbiot are based on the classification of total volatile organic compounds of the German Federal Environmental Agency, above which, depending on the exposure time, they can lead to allergic and sensitizing reactions, hypersensitivities or diseases of various pathologies.

Based on this classification, the following ranks have been established in My inBiot:

4. Unit of measurement

The concentration of total organic compounds in air is determined in ppb (parts per billion).
The relationship between ppb and µg/m³ is not straightforward, as the TVOC ratio is the sum of a number of compounds with different behaviors and molecular weights. The TVOC value is calculated as the sum of all detected compounds from the equivalent value of toluene for each of them, according to UNE-EN 16516:2018+A1:2021.

In addition, because of the difficulty in determining TVOC concentration due to the wide variety of compounds involved, it is possible to determine TVOC levels with relative units (Index Points) that define the trend and amplitude of concentration changes. These relative measurements can be converted to absolute concentration using conversion factors.

5. Sources

Volatile organic compounds are present in solvents, paints, glues, varnishes and the like, in plastics, furniture, building materials (insulation, finishing boards, foams), cleaning, hygiene and maintenance products in buildings. They are common compounds, easily found in building interiors.

6. Benefits of optimal levels  

We spend 80-90% of our time indoors. Our interrelationship with factors such as temperature, humidity, air renewal or the presence of volatile organic compounds characterise a suitable indoor environment and condition our health.
An indoor environment without the presence of harmful volatile organic compounds will be an indoor environment focused on health, without the presence of irritating and/or potentially allergic substances, guaranteeing comfort and well-being, with positive impacts on the productivity and creativity of its occupants.

7. Risks of inadequate levels

The risk from the presence of VOCs occurs mainly during the use of products containing VOCs and in the first days and weeks immediately after use. Some of the most common VOCs with the highest health impact are being replaced by alternative compounds. However, these have higher boiling points, so they can off-gas for longer and pose, like the VOCs they replace, significant health risks.

The health effects are diverse, depending on the compound and the period of exposure. VOCs are generally fat soluble and in the short term may cause allergic reactions, headache, mucosal irritation, itchy nose, red eyes, coughing, fatigue, dizziness or skin spots. In the long term, they can damage the liver, kidneys or the central nervous system, and some of them can be carcinogenic.

8. Recommendations for improvement

  • Adequate air renewal.
  • Elimination of the polluting source.
  • Use of construction and finishing products certified with low VOC emissions (EC1 plus).
  • Review of hygiene and cleaning products.

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