Research by Indiana University environmental scientists shows that air-pollution-removal technology used in “self-cleaning” paints and building surfaces may actually cause more problems than they solve.
The study finds that titanium dioxide coatings, seen as promising for their role in breaking down airborne pollutants on contact, are likely in real-world conditions to convert abundant ammonia to nitrogen oxide, the key precursor of harmful ozone pollution.
“As air quality standards become more stringent, people are going to be thinking about other technologies that can reduce pollution,” said Jonathan D. Raff, assistant professor in the School of Public and Environmental Affairs at IU Bloomington and an author of the study. “Our research suggests that this may not be one of them.”
“Photooxidation of Ammonia on TiO2 as a Source of NO and NO2 under Atmospheric Conditions” is being published by the Journal of the American Chemical Society and is available online. Other authors include SPEA doctoral students Mulu Kebede and Nicole Scharko, Mychel Varner of the University of California-Irvine and R. Benny Gerber of UC-Irvine and the Hebrew University in Jerusalem.
The researchers calculate that, in areas where the titanium dioxide technology is used, ammonia degradation could account for up to 13 percent of the nitrogen oxides in the immediate vicinity. This suggests that widespread use of the technology could contribute significantly to ozone formation.
The findings are timely because the Environmental Protection Agency is developing stricter regulations for ground-level ozone, a primary component in photochemical smog. The pollution is linked to serious health problems, including breathing difficulties and heart and lung disease.
Read more at: Phys.org