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Titanium Dioxide: A Pollution Solution?

By Brock Dodds

September 9, 2023

UPDATED 12:00 PM EST



Pollution is becoming a major threat to health in urban areas worldwide. Solutions proposed vary from restrictions on automobiles to new fuel and exhaust technology. In the wake of record-breaking heat and worsening air quality in the United States and around the world, the effect climate change and pollution have on urban life is in the spotlight. Researchers are looking into the challenges of implementing a compound called titanium dioxide that has been proven to remove pollutants from the air. The prospect of titanium dioxide “cleaning” air has been developing since the early 2010s, with researchers in Spain, the United Kingdom, the Philippines, and many more locations developing compounds designed for the application of titanium dioxide to surfaces. In 2022, evidence was published in the International Journal of Preventive Medicine that titanium dioxide can also photoclean indoor pollutants such as carbon monoxide and formaldehyde. It is evident TiO2 has moved from a proof-of-concept, entrepreneurial invention to a serious consideration for pollution mitigation, as recent research on TiO2’s pollution control potential has moved to questions of complex and large-scale implementation. In 2021, engineers at Bina Nusantara University in Jakarta began to analyze the best strategies for implementing TiO2 coatings on apartment buildings to maximize their anti-pollution impacts.

TiO2 cleans the surrounding air via its photocatalytic properties. It attracts pollutants, such as nitrogen dioxide, which then bind to its molecules. Once nitrogen dioxide is essentially stuck to the TiO2 surface, UV light completes the process, turning nitrogen dioxide into simple salt that mixes with water. However, there are significant limitations. Say one covered an entire apartment building in TiO2–even this amount would only be sufficient to clean the air immediately surrounding the building. The minimal impact-to-effort ratio hampers TiO2’s effectiveness in urban areas. By its nature, titanium dioxide can only clean air in its close proximity, making it potentially useful in pockets of intense pollution near a specific building, but not much else. Additionally, the Jakartan engineers found that the shape of apartment buildings and other application sites would need to be modified to maximize surface area for a tangible effect in the air surrounding the building.

While titanium dioxide does show promise for tactically placed air cleansing in the most polluted areas of the urban landscape, there are certainly risks. Material scientists have warned that TiO2 poses dangers to human health, which would therefore be at risk if titanium dioxide were to coat living spaces (not to mention the increased production necessary for a full implementation). For over a decade, the International Agency for Research on Cancer has held that titanium dioxide is a possible carcinogen. Research published in Radiology and Oncology finds that titanium dioxide nanoparticles can damage cells and elicit an immune response. The damage to soil and the environment from TiO2 nanoparticles is even more widespread. Researchers at Duke University and the University of Lyon conducted tests on the effect TiO2 nanoparticles have on soil. They found that they can disturb the key process of the nitrogen cycle and have high levels of ecotoxicity due to soil’s low resilience to nanoparticles. The microorganisms necessary to several mechanisms involved in soil’s micro-ecosystem all face threats from TiO2 contamination, researchers found. Given that TiO2 coatings will be in high-traffic areas with high sun exposure, it is very likely that a large-scale implementation of them could pose a risk to human health and the environment.

Given the urgency of addressing climate change and environmental danger, we often jump at new advancements that promise to alleviate these issues. But it’s important to remember to dig deeper into any claim of a technology that is a solution to pollution and climate change. Often, said technologies can have significant drawbacks. Solving climate change and environmental degradation will require consistent development of new technologies and methods, but will also require rigorous testing and experimentation to ensure that these advances don’t end up harming the environment further. Fossil fuels were once thought to be perfectly safe, after all–rushing into promises of quick and easy fixes to climate change risks imperiling us further.


References

Burton, Adrian. “Titanium Dioxide Photocleans Polluted Air.” Environmental Health Perspectives, vol. 120, no. 6, June 2012, https://doi.org/10.1289/ehp.120-a229.

Simonin, Marie, et al. “Titanium Dioxide Nanoparticles Strongly Impact Soil Microbial Function by Affecting Archaeal Nitrifiers.” Scientific Reports, vol. 6, no. 1, Sept. 2016, https://doi.org/10.1038/srep33643.

Skocaj, Matej, et al. “Titanium Dioxide in Our Everyday Life; Is It Safe?” Radiology and Oncology, vol. 45, no. 4, 1 Jan. 2011, www.ncbi.nlm.nih.gov/pmc/articles/PMC3423755/ , https://doi.org/10.2478/v10019-011-0037-0

Subagio, G B, et al. “Use of Titanium Dioxide in Apartments Building to Reduce Air Pollution.” IOP Conference Series: Earth and Environmental Science, vol. 794, no. 1, 1 July 2021, p. 012207, https://doi.org/10.1088/1755-1315/794/1/012207.


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