Israeli scientists are reporting that thirdhand smoke – the invisible remnants of cigarette smoke on carpeting, clothing, furniture and other surfaces – may be even more of a health hazard than previously believed. According to a new study by the Technion-Israel Institute of Technology (IIT), so-called thirdhand smoke increases the risk of respiratory illnesses among people who do not smoke.

Dr. Yael Dubowski and colleagues at the IIT reported that thirdhand smoke is a newly recognized contributor to the health risks of tobacco and indoor air pollution.

The study was published in the American Chemical Society journal, Environmental Science & Technology.

Dr. Dubowski and her team studied interactions between nicotine and indoor air on a variety of different materials, including cellulose (a component of wood furniture), cotton, and paper to simulate typical indoor surfaces. They found that nicotine interacts with ozone, in indoor air, to form potentially toxic pollutants on these surfaces.

The scientists said that the risk for young children, who are more likely to be crawling on carpets, is especially concerning. The report also showed that people napping on tainted sofas or eating food that may have been previously exposed to thirdhand smoke are also at increased risk.

“Given the toxicity of some of the identified products and that small particles may contribute to adverse health effects, the present study indicates that exposure to [thirdhand smoke] may pose additional health risks,” the article notes.

The report said that exposure can result in reduced white blood cell activity, asthma and other mutagenic effects.