As the European Union (EU) embarks on its ambitious journey towards a carbon-neutral future, the construction sector faces a huge challenge: the need to transform a staggering 97% of the existing building stock into zero-emission structures by 2050. This undertaking demands a rapid and comprehensive approach, but it is crucial to carefully consider ripple effects, such as embodied greenhouse gas (GHG) emissions.
Embodied GHG emissions are the carbon footprint hidden inside the materials used to build and maintain homes. Unlike emissions from heating our homes, running lights, and appliances (operational emissions), embodied GHG emissions occur throughout the life cycle of a building material, from the extraction of raw materials to the transportation, manufacturing, installation, and eventual disposal of building materials. When we consider the embodied GHGs of a building, we essentially look at the cumulative carbon footprint of all the materials that went into its construction.
Imagine you are baking a cake. The operational emissions would be the energy used to bake the cake, whereas the embodied GHG emissions would be the emissions from growing wheat, raising chickens, and processing sugar and flour. Therefore, when we talk about reducing embodied GHG emissions, we are essentially looking for ways to make buildings more sustainable by choosing materials that have a lower carbon footprint.
One hidden carbon footprint in building materials is per- and polyfluoroalkyl substances (PFAS), a class of over 10,000 chemicals that have been widely used since the 1950s in manufacturing processes and consumer products. PFAS are formed by a unique chemical reaction that creates a bond between carbon and fluorine, which is the strongest bond in organic chemistry. Owing to their persistent, toxic, and bioaccumulative nature, they have been linked to a range of health and environmental problems, including cancer, impaired immune function, and reproductive and developmental problems.
In the construction industry, PFAS are often used to make buildings more durable and resistant to water, oil, dust, heat, and other elements. In addition, PFAS play a critical role in the development of clean energy solutions. However, the production and use of PFAS contributes significantly to embodied GHG emissions. This is because the manufacturing of PFAS is an energy-intensive process and emits greenhouse gases worse than carbon dioxide if not contained. Some PFAS degrade into more damaging compounds, which also leads to embodied GHG emissions during their lifespans.
In this brief, I reflect on the ripple effect of PFAS on the embodied GHGs in construction and renewable energy materials. In addition, I develop key messages to guide regulators and policymakers.
PFAS use in the manufacture of renewable energy technologies.
EU policymakers find themselves between a rock and hard place. They grapple with the dilemma of choosing between banning PFAS to reduce health impacts or balancing climate targets without hindering renewable energy progress. The EU faces mounting pressure for its proposed complete ban on PFAS. Balancing energy transition objectives without impeding progress towards a carbon-neutral future is crucial, but so is the protection of public health and the environment.
The pressing need for thoughtful consideration of PFAS in relation to energy transition and the construction industry is highlighted by the projected annual growth rate of 10% in the use of PFAS in the energy sector, according to the proposed PFAS restriction report. With numerous energy solutions available such as solar, wind, hydro, tidal, geothermal, biomass, hydrogen, residual heat, and nuclear fusion, the report indicates that further investigation is needed in areas where PFAS use is increasing, such as fuel cells, hydrogen technology, and rechargeable batteries.
In the solar energy sector, PFAS coatings play a critical role in enhancing the performance, durability, and efficiency of solar energy systems. These coatings improve transparency, UV and heat resistance, mechanical strength, and dirt repellence of solar panels. PFAS polymers are also used in EU batteries, with projections indicating a substantial increase in usage from 15,000 to 20,000 tons by 2030.
Hydrogen, an emerging energy solution, faces challenges due to the proposed EU PFAS ban. It is anticipated that employment associated with PFASs will increase to attain the 2030 EU Hydrogen Strategy goal of 40 GW electrolysis capacity. Proton exchange membrane (PEM) electrolysis technology, which utilises PFASs, can help achieve this goal. Fluoropolymers, a subset of PFAS, are crucial in electrolysers and fuel cell applications, as acknowledged by Hydrogen Europe. The industry, estimated to be worth €30 billion in investment, has the potential to create up to 200,000 direct and 260,000 indirect jobs, contributing to a market value of €820 billion and employing 5.4 million people by the middle of the century.
A recent position statement by the Hydrogen Council articulates the role of fluoropolymers and perfluoropolyethers in the ongoing energy transition. According to the Council, "Fluoropolymers and perfluoropolyethers are vital to the critical industries that are the foundation of our sustainable future, including the hydrogen infrastructure, semiconductor manufacturing, and electric vehicle (EV) batteries”. The statement asserts that "a one-size-fits-all regulatory approach for this wide range of substances is avoided". The Council further explains that: "Life cycle impacts of fluoropolymers do not pose any threat to human health or the environment when used in the hydrogen economy provided that principles of responsible manufacturing are respected." The Council also echoes a resounding caution to regulators that, "A blanket restriction or ban of all PFAS subclasses will have a negative impact on the introduction and commercialization of hydrogen technology and therefore significantly stall the progress towards net zero goals." However, research reveals that replacing hazardous PFAS with other potentially hazardous PFAS of unknown chronic toxicity is not a viable solution. The study concludes that “the only answer is a switch to fluorine-free alternatives for all applications in which PFAS are not essential.” With differing opinions on what should be the way forward, the EU should adopt a precautionary approach and maintain the current one-size-fits-all regulatory approach.
The Hydrogen Council's conclusion is that “regulatory uncertainty will drive the downstream critical product manufacturers to postpone or move their investments from the U.S. and EU to other geographies.” This will potentially contaminate our shared air, water, and other environmental pathways. Some PFASs have high mobility and relocation may not protect the EU from their adverse impacts.
One strategy to address PFAS challenges is to prioritize prevention. This includes identifying and eliminating non-essential uses of PFAS, to allow time for safer alternatives to be developed for essential applications. This approach has been expressed in the 2015 Madrid Statement, and various manufacturers and organizations are currently assessing methods to remove PFAS from their supply chains and building materials.
The proposed PFAS ban separates essential and non-essential uses and provides special and differential treatment to these two groups. Figure 1 shows the projected increase in PFAS emissions from the energy sector between 2035 and 2060, which declines to net-zero emissions with a 5-year derogation. The restriction proposal recommends “a full ban with a transition period of 18 months ... [and] A use-specific 5-year derogation,” for the energy sector to achieve net-zero emissions by 2033. The proposed derogation applies to fluoropolymers and perfluoropolyethers in PEM fuel cells to allow hydrogen and energy technologies to replace PFAS with safer alternatives.
Figure 1. Time path of mean emissions under the baseline, RO1 and the maximum additional emission scenario (energy sector, in tonnes). Source: European Chemical Agency (ECHA).
PFAS regulatory landscape is complex and unpredictable, making its restriction and subsequent ban difficult. These so-called "wicked problems" defy simplistic, black, and white solutions, leading to derogations. Derogations complicate the regulatory landscape, but focusing on embodied GHG emissions could simplify tracking and reduce PFAS footprint.
Ubiquitous PFAS use in buildings.
As we shift to renewable energy, the building and construction sectors are equally crucial. Retrofitting and energy-efficient features can significantly cut energy use and environmental harm. This involves insulating homes, upgrading boilers, and using electric induction heating instead of gas cookers.
PFAS are widely used in building materials due to their performance and longevity. A report from the Green Science Policy Institute found that PFAS have permeated the building industry and are used in a variety of applications. The following examples demonstrate their persistent use in various building applications.
- Roofing: PFAS are widely used in roofing materials to enhance their performance and durability. They are used in coatings on metal sheets, shingles, flashing, and nails to provide scratch resistance, prevent colour loss, and improve corrosion resistance. Asphalt roofing with PFAS-coated granules has better aesthetics, weather protection, stain resistance, and UV resistance. Fluoropolymers are used in weather-proofing membranes to control moisture and increase durability. Tensile roofing such as retractable structures and shade fabrics benefits from the strength and low maintenance of fluoropolymers. PFAS are also used in rain gutters to repel dirt and facilitate easy cleaning.
- Flooring: Flooring materials like carpets, rugs, resilient flooring, and artificial turf often have PFAS added to make them water, stain, and soil repellent. Some major carpet manufacturers and retailers have stopped using PFAS, while others continue to use it in after-market protectors, finishes, waxes, and polishes. PFAS are also used in seismic damping systems to improve earthquake resilience in structures, such as buildings and bridges.
- Glas: Windows, Doors, and Lightbulbs: Glass products, including windows, doors, and light bulbs, are improved by the addition of PFAS, which enhance durability, heat resistance, and anti-dust properties. Fluoropolymer coatings on light bulbs extend their lifespan and maintain their original colour, temperature, and shading. As a result, PFAS increases the longevity and appearance of glass products.
- Coating and Finishes: PFAS are widely used in coatings and finishes to enhance properties such as non-stick features, graffiti resistance, anti-corrosion properties, gloss, and durability. They are also used in wood lacquers as a wetting agent and in plastic coatings for longevity and resilience.
- Sealants and Adhesives: Fluorinated sealants and adhesives, like grout, tile, and concrete sealers, protect materials from stains, mould, and damage. They provide a clear, long-lasting finish and are resistant to environmental elements. PFAS-containing caulks are used in structures to fill gaps, enhance durability, and reduce dust. Fluoroelastomer O-rings with PFAS are used in high-stress applications. PFAS improve bond strength in construction adhesives by increasing penetration and wettability, ensuring superior spread and increased contact area when bonding tiles, flooring, drywall, ceilings, wood, and moulded structures.
- Wires and Cables: PFAS are widely used in electrical wiring and sealing materials, providing effective insulation for various applications. They also play a critical role in creating a secure seal in thread-seal tapes. PFAS enhance the performance and longevity of building components by preventing leakage and reducing friction and rust.
- Tape: PFAS are widely used in plumber tapes and fluorinated fibreglass in the building sector. PFAS-containing tapes are utilised in window and door manufacturing and flooring applications to secure carpets and resilient flooring to the subfloor. Fluoropolymers are used as protective coatings for adhesive tapes before application and are disposed after use.
- Fabrics: Furniture, Curtains, Awnings: PFAS treatments enhance the stain, soil, and water-repellent properties of various textiles, including furniture, curtains, and fabric awnings, and can be applied during manufacturing or as post-treatment sprays to ensure comprehensive coverage. PFAS-treated fabrics maintain a clean and attractive appearance over time, making them ideal for high-traffic areas and water- and stain-proof fabric awnings, thereby extending their longevity and aesthetics.
The Green Science Policy Institute report shows that PFAS are present in various buildings, but there is limited information available on whether certain building components contain PFAS and feasible alternatives. To bridge this gap, straightforward and transparent methods for identifying PFAS in building materials are urgently needed.
Fortunately, safer, and non-fluorinated alternatives are now available for many PFAS uses in building materials. While the report outlines potential alternatives to fluorinated compounds, it emphasizes the importance of rigorous due diligence to assess potential hazards and functionality. Transparency is crucial in identifying safer alternatives, and it is essential to communicate the pros and cons of each alternative, such as price, durability, safety, and waterproofness.
Three key messages for regulators and policymakers.
PFAS has infiltrated virtually every nook and cranny in our buildings. From construction materials to everyday products, PFAS are omnipresent and silently pose a threat to public health and the environment. Envision a world where our buildings are not unwitting reservoirs of PFAS but bastions of safety and sustainability. Imagine a future where homes embody zero GHG emissions, free from clutches of these persistent chemicals, where materials and products enhance, rather than compromise, our well-being. To achieve this future, three crucial messages (with proposed action points) emerge for EU policymakers and regulators.
In conclusion, a holistic PFAS regulatory approach is imperative for a resilient and decarbonised future. A dual focus on reducing embodied GHG emissions and addressing energy and construction industry challenges is critical, requiring a delicate equilibrium between regulatory measures to protect the environment and human health and use-specific derogations to ensure that energy transition and climate change targets are met.
- Researcher