Roofing Sustainability Bituminous Membrane

Air pollution in urban areas driven largely by Nitrogen oxides (NOx) poses a dire health threat, with the WHO attributing it to over three million deaths worldwide.³ Nitrogen Dioxide (NO2), a primary component of NOx, results predominantly from vehicles and industrial emissions, leading to severe respiratory issues and environmental concerns like acid rain. As the battle against these pollutants intensifies, Sika introduces its innovative solution: the SikaShield® Pure-Air roof membrane.

Aerial view of Amsterdam city roofs

The Current Status of Air Pollution

Emissions of Air Pollutants1
graph for the emissions of air pollutants

Among the different harmful components of air pollution, Nitrogen oxides, commonly referred to as NOx, account for more than 33%2. Nitrogen Dioxide (NO2) is one of a group of highly reactive gases known as nitrogen oxides (NOx). It gets in the air from the burning of fuel from cars, trucks and buses, power plants, and off-road equipment. Breathing air with a high concentration of NO2 can irritate airways in the human respiratory system leading to respiratory symptoms (such as coughing, wheezing or difficulty breathing) and may contribute to the development of asthma and potentially increase susceptibility to respiratory infections1.

From an environmental perspective, NOx contributes to nutrient pollution in coastal waters as well as to the formation of acid rain, which harms sensitive ecosystems such as lakes and forests. Despite decreasing since 1990 (thanks to the introduction of particle filters, catalytic converters and stricter emissions regulations), NOx emissions are still significantly high and can be linked to 38,000 premature deaths worldwide, according to new research3. Therefore, one of the most fundamental challenges nowadays, is to contrast NOx emissions3.

Pioneering Clean Air Solutions with SikaShield® Pure-Air

white sikashield pure air roof

In an age where environmental sustainability is paramount, Sika presents its groundbreaking solution:

SikaShield® Pure-Air

This innovative bituminous membrane is a testament to Sika's unwavering dedication to sustainability.

More than just a standard bituminous membrane, SikaShield® Pure-Air is infused with advanced TiO2-based technology. This unique feature empowers it to efficiently capture and eliminate detrimental pollutants, primarily emitted from vehicle exhausts and industrial processes. The result is a significant reduction in smog levels, fostering a more eco-friendly urban and industrial atmosphere.

The brilliance of this product lies in the white granules of TiO2 embedded on top of the membrane. These granules are the champions behind the cleaning prowess of SikaShield® Pure-Air, ensuring consistent air purification, a cleaner environment, and a step towards greener cities and industrial areas.

White granules of TiO2 on top of the membrane guarantee the cleaning function of the product.
sikashield pure air product shot with zoom in of Tio2 white granules
The ensured
of a standard Sika bitumen membrane
function of titanium dioxide technology

SikaShield® Pure-Air in Action

For a deeper understanding of the revolutionary potential of Sika’s bituminous membrane, watch our comprehensive video.

How Does It Work

SikaShield® Pure-Air stands at the forefront of innovation, offering a tangible solution to combat harmful air pollutants.
But how does this groundbreaking technology work? Let’s take a look at the process, step by step.

1. Activation by UV Radiation

The surface slates of SikaShield® Pure-Air are coated with titanium dioxide (TiO2). This substance acts as a catalyst, which is activated when exposed to UV radiation from the sun. Once activated, it releases the necessary energy to break down the NOx particles in the atmosphere.

SikaShield Pure-Air drawing - The UV Radiation Activates  the TiO2
2. Conversion through Chemical Reaction

As NOx particles come into contact with the energized TiO2 surface and the ambient water vapor, a chemical transformation occurs. The result of this reaction is the formation of nitric acid (HNO3), effectively removing harmful NOx compounds from the surrounding air.

SikaShield Pure-Air  drawing - NOx are converted into HNO3 by chemical reactions
3. Regeneration through Natural Processes

Nature plays its part in ensuring the longevity and efficacy of the SikaShield® Pure-Air membrane. When rainwater cascades over the surface, it washes away the HNO3. This cleansing process not only purifies the membrane but also rejuvenates the catalytic function of the TiO2, thus renewing it for a fresh cycle of pollutant removal. Importantly, this regenerative cycle continues throughout the entire lifespan of the roof, ensuring sustained air purification.

SikaShield Pure-Air drawing - The rain washes out the HNO3, regenerating the membrane



ISO-Certified Air-Cleaning Functionality

Icon of certificate showing product to meet high standards

SikaShield® Pure-Air's dedication to sustainability and improved air quality has been thoroughly validated. Under rigorous testing conditions, a specialist German laboratory undertook an evaluation of the product's photocatalytic performance. The results were benchmarked against the ISO 22197-1 standard.

Notably, SikaShield® Pure-Air displayed a remarkable NOx reduction capacity of 6.12 mg/m2 per hour. This performance was recognized by the Federation for Air Purity (FAP) as a significant indicator of good degradation efficiency. This makes an incredible contribution to reduce the air pollution by NOx compounds, especially from road transportation, which is the primary contributor to air pollution.

Key Advantages

ISO Certification: Meets the ISO 22197-1 standard for photocatalytic activity with an impressive NOx degradation rate of 6.12 mg/m2 per hour.

Significant Contribution to Cleaner Air: Specifically targets and reduces NOx pollutants primarily released by road transportation, a predominant contributor to air pollution.

Natural Activation: Makes efficient use of natural resources by being activated through sunlight, diminishing the need for external energy sources.

Environmental Impact: Helps mitigate the environmental consequences of human activities, endorsing a more sustainable future.

Societal Improvement: Air quality remains at the forefront of societal challenges. SikaShield® Pure-Air actively addresses this by setting improved air quality as a key goal.

Quantifying the Impact


KM Cleaned by SikaShield® Pure-Air
graph of KM cleaned SikaShield® Pure-Air

* Reference: Pollutant emissions from transport – Products Datasets – Eurostat (


To visualize the sheer impact of SikaShield® Pure-Air, consider this: a diesel truck driving through suburban areas at speeds ranging from 40-80 km/h emits an average of 1.5 g/km of NOx.
Given this data:

A coverage of 10,000 m2 of SikaShield® Pure-Air possesses the capacity to purify the emissions from over 104,000 km of truck travel annually in the USA.

Expanding this to 100,000 m2 scales up the cleaning potential to an astounding 770,000 km annually in Europe.

On a grander scale, 1,000,000 m2 of this innovative membrane can tackle the emissions from a staggering 13 million km every year, when considering just Europe and the USA combined.

product shot of sikashield pure air roll

These statistics not only underline the immense potential of SikaShield® Pure-Air, but also solidify its position as a pioneering solution in the quest for better air quality and a more sustainable environment.

Learn More

As the world strives for a better tomorrow, SikaShield® Pure-Air is not just a product but a step towards cleaner air and sustainable living. Let's make a tangible difference together – download our brochure for comprehensive insights into the technology, benefits, and real-world impact of SikaShield® Pure-Air.

Alternatively, contact us directly to find out more. Our team of experts is always available to answer your queries, discuss potential collaborations, or help you integrate SikaShield® Pure-Air into your projects.

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3Source: EMISSIONS OF AIR POLLUTANTS EU-27, 1990 – 2018
(INDEX 1990=100)