Formaldehyde: Risks, Exposure Limits, and Detection

Formaldehyde is a common compound with a wide variety of industrial uses. Small concentrations are in the air that you, your employees, and your family breathe every day - and it could be enough to put their health at risk.

Formaldehyde (CH₂O) is a colorless gas at room temperature. Its distinctive pungent odor makes it easy to detect at first encounter, but awareness of the odor dissipates quickly.

Small amounts of formaldehyde are produced by manual processes, but most of the airborne formaldehyde we encounter has been created for industrial use. The aqueous solution of formaldehyde used in industry is known as formalin.

• Formalin is used as a bonding agent and coating in the manufacture of common construction materials such as plywood, particle board, and laminate flooring. 
• Formaldehyde is used as a preservative for cloth used in carpets, draperies, and furniture manufacturing, where it increases durability, allows dyes to penetrate more deeply, and helps fabrics resist wrinkles. 
• Formaldehyde is also found in some glues, air fresheners, cleaning products, cosmetics, and detergents.

Formaldehyde is easy and inexpensive to produce, and it is effective in a broad range of common applications. The NIH reports that manufacturers create and use about 21 million tons of formaldehyde every year.

When products that have been treated with formaldehyde are present, the compound is released as a gas into the air, where it can build up to hazardous concentrations without anyone noticing.

Formaldehyde as a Volatile Organic Compound

Formaldehyde is classified as a volatile organic compound. It shares properties with the VOCs that are found in industrial solvents, water chlorination systems, gasoline, paint thinner, and dry-cleaning solvents. Chief among these properties is the VOC’s tendency to be emitted as a gas from liquids and solids that contain it or have been treated with it.

VOCs are among the most serious health threats. When concentrations are too high or last too long, VOCs can cause serious health problems, including damage to the liver, kidneys, or central nervous system. Some VOCs have been shown to cause cancer.

Formaldehyde pollution is easily detected because of the compound’s distinctive odor, but people acclimate to it quickly, and may not even be aware that their indoor air quality has been compromised. This can happen even in rooms and buildings that are considered well-ventilated.

Given its widespread use in everyday products and the fact that even human exhalations contain a small amount of formaldehyde, low concentrations are found in all indoor environments. Formaldehyde becomes a problem only when concentrations are sufficient to compromise the health of occupants.

Formaldehyde pollution has many sources:

• It is commonly used as a coating in office furniture, especially furniture composed of plywood or particle board.
• It is found in office carpeting and flooring.
• It is present in office equipment such as printers and copiers.
• It is used in the production of paper, and is therefore emitted by office paper supplies.
• It is used in the insulation, adhesives, sealants, and paints used in the construction of commercial spaces.
• It is present in the materials used in some HVAC systems.
• It is found in cleaning agents, air fresheners, glue, paint, pesticides, and detergents.
• It is emitted as a byproduct of 3D printing and vaping.
• It is released by combustion processes in gas stoves, tobacco products, candles, and vehicle exhaust.
• Small amounts of formaldehyde are naturally present in coffee, carrots, bananas, apples, and other foods.
• Formaldehyde is naturally present in human exhalations.

Formaldehyde’s concentration, like the concentration of other pollutants, can be expressed in micrograms per cubic meter (µg/m³) or parts per million (ppm).

A concentration of 1 µg/m^3, means that within every cubic meter of air, there is 1 microgram of formaldehyde. A concentration of 1 ppm means that for every million molecules of air, there is one molecule of formaldehyde.

These measures depend on formaldehyde’s molecular weight of 30.026 grams per mole. At 25 ºC and 1 atmosphere of pressure, the conversions are:

concentration (mg/m3) = 0.0409 x concentration (ppm) x 30.026 g/mol

concentration (ppm) = 24.45 x concentration (mg/m3) / 30.026 g/mol

IAQ monitors collect air samples and measure the mass of pollutants in the sample. The concentration is then expressed in µg/m3 or ppm (ppb).

Outdoors, formaldehyde is quickly dissipated. Concentration levels range from 0.0002 to 0.02 ppm. 

Indoors, where concentrations can rise to 10 ppm or even 20 ppm or higher in buildings that have recently been built or restored, formaldehyde exposure has become a serious health risk - particularly for children, the elderly, and people with asthma or other breathing problems.

According to the Centers for Disease Control and its Agency for Toxic Substances and Disease Registry (ATSDR), exposure to 10-20 ppm of formaldehyde causes eye irritation and a burning sensation in the nose or throat almost immediately.

Short-term exposure to formaldehyde can irritate the eyes, nose, and throat. It can cause respiratory issues such as coughing and wheezing. And it can lead to headaches, dizziness, and nausea. 

At higher concentrations, even short-term formaldehyde exposure can cause skin rashes, shortness of breath, and changes in lung function. The CDC reports that exposure to 50-100 ppm of formaldehyde could cause serious injury to lower respiratory passages in as little as 5-10 minutes.

Long-term effects can be serious. Exposure to formaldehyde can lead to chronic respiratory conditions such as asthma and bronchitis. The compound is classified as a Group 1 carcinogen by the International Agency for Research on Cancer. And it can have serious effects on reproductive health and development.

Some people are especially vulnerable to formaldehyde’s health risks. For example, people with chronic respiratory conditions like asthma and COPD can find their conditions worsened due to long-term formaldehyde exposure. Pregnant women, children, and the elderly may also be more sensitive to the health effects.

The EPA defines formaldehyde as a contributor to increased sensory irritation and respiratory tract pathology, decreased pulmonary function, increased symptoms of asthma, increased allergic responses, reproductive toxicity in men and women, and developmental toxicity in females.

Because of these effects, industry regulatory bodies and government agencies have issued regulations, guidelines, and standards for formaldehyde exposure.

The U.S. Occupational Safety and Health Administration has a distinct standard for formaldehyde. OSHA defines a permissible exposure level of 0.75 ppm measured as an eight-hour time-weighted average. The regulation allows for a short-term exposure limit of 2 ppm for a 15-minute period.

The National Institute for Occupational Safety and Health defines dangerous levels of pollutants as IDLH: immediately dangerous to life and health. A formaldehyde concentration level of 20 ppm is considered IDLH.

EPA does not specifically prescribe enforceable indoor air quality regulations for formaldehyde. The agency does provide information on formaldehyde’s toxicological effects, however. An EPA Integrated Risk Information System toxicological review concluded that when inhaled, formaldehyde can cause nasopharyngeal cancer, sinonasal cancer, and myeloid leukemia. EPA has established a reference formaldehyde concentration of 7 micrograms per cubic meter. This concentration is defined by the EPA as “the level of continuous inhalation exposure to the human population (including sensitive subgroups) that is likely to be without appreciable risk of deleterious effects during a lifetime.”

For more on the benefits of monitoring air quality, see Why is it important to monitor air quality in office buildings?

The first step in improving air quality and minimizing the dangers of formaldehyde and other VOCs is to measure current exposure levels. There are several questions to consider.

Is it better to employ spot sampling or continuous monitoring?

There are three major methods of measuring air quality.

• Passive sampling systems employ an absorbent material that collects samples of pollutants through their natural diffusion throughout the environment. This solution doesn’t require a pump to force air through a filtration system, and it doesn’t require frequent maintenance. However, the data is imprecise due to changing environmental factors and lower sensitivity. Passive sampling doesn’t provide real-time data.
• With active sampling, a defined quantity of air is drawn through a filter at a controlled rate. The sample is analyzed to provide a real-time report of pollutant concentrations. These systems offer higher precision than passive solutions at the cost of higher cost, more complexity, and the need for electrical power. Active sampling systems require regular maintenance and calibration.
• Continuous IAQ sensors and monitors provide ongoing measurement of contaminant concentrations. Dashboards provide real-time readings of air quality, and monitors can alert occupants when pollution levels rise to specified limits. In most circumstances, this is a higher level of useful information that makes it easier to mitigate problems.

How do IAQ sensors and monitors detect formaldehyde?

IAQ sensors and monitors can measure formaldehyde concentrations using two methods.

• Some systems measure the presence of a selection of VOCs, reporting a TVOC figure representing total VOC concentration. A high TVOC reading can alert users to perform further investigation with professional-grade equipment to identify the specific VOC and its health impact.
• Other systems perform direct testing for particular VOCs, reporting concentrations of each VOC separately.

For example, Atmocube IAQ monitor performs continuous monitoring and separately reports the concentration of formaldehyde.

Monitoring systems can alert management when ventilation systems need to be upgraded and they can identify air quality hotspots that require special attention. A variety of actions can be taken to improve air quality.

• HEPA filters and activated carbon can capture formaldehyde and other VOCs, reducing or eliminating their threat to occupant health.
• Simple steps like treating carpet and office furniture can remove surface-level formaldehyde left over from manufacturing, reducing indoor concentrations substantially. 
• It’s also important to purchase building materials that have been certified by CARB, the California Air Resources Board.
• Because formaldehyde is released by burning, air quality can be improved by ensuring that kitchens are well-ventilated and equipped with range hoods.
• Eliminating indoor smoking, candles, and incense burning can also reduce formaldehyde concentration.
• Allow new furniture and draperies to air out in a well-ventilated area for a couple of days before bringing them indoors.
• Wash new clothing before wearing it.

Encouraging Awareness 

It is important to raise awareness about formaldehyde exposure in workplaces and living spaces. Employees and other occupants should learn to recognize symptoms of VOC exposure and the importance of reporting their concerns. And building managers should communicate the importance of ventilation and minimizing the use of certain products.

An air quality dashboard like Atmocube’s can play a central role in detecting, pinpointing, and addressing problematic concentrations of formaldehyde, other VOCs, and other pollutants.

Formaldehyde is present in all indoor environments. The trick is to understand safe exposure levels, monitor air quality, and take steps to reduce harmful concentrations when they are detected.

Scientific studies increasingly identify indoor air pollution as a source of health risks. While there are many kinds of pollution, VOCs like formaldehyde are implicated in some of the most serious long-term health problems.

Air quality monitoring systems are an essential part of the solution. They allow us to detect and localize sources of pollution while measuring the effectiveness of remediation efforts and technologies. Air quality monitoring can help reduce health risks while creating a more pleasant and comfortable environment.