Anthrax flattened by air cleaning system

An indoor air cleaning system originally developed to kill dust mites and mould spores also destroys airborne anthrax and other pathogenic microbes, claims the University of Florida engineering professor who pioneered the technology.

The system has been successfully tested against a close cousin of the anthrax bacteria and could be installed relatively inexpensively and quickly in office and home heating and air conditioning systems, said Yogi Goswami, a UF professor of mechanical engineering and director of UF’s Solar Energy and Energy Conversion Laboratory.

‘There are other technologies for air cleaning, but for air disinfection, there is no more effective system,’ Goswami said.

The photocatalytic air cleaning system is said to rely on the interaction between light and titanium dioxide. When light is absorbed into the titanium dioxide, it acts as a catalyst to produce an oxidising agent. The agent, a hydroxyl radical, ‘is like a bullet for the bacteria,’ said Goswami, destroying dust mites, mould spores and pathogens by disrupting or disintegrating their DNA.

Goswami came up with the system in the mid 1990s as a cure for ‘sick building syndrome,’ when poor ventilation and a build-up of mould or mildew caused illnesses for people working inside. Initial research proved that the system kills the mould spore, aspergillus niger, considered to be one of nature’s hardiest spores, he said.

More recent research has shown that the system also destroys bacillus subtilis, a spore that causes food spoilage and is a cousin of the anthrax spore, bacillus anthracis.

‘In the laboratory, we normally test with nonpathogenic bacteria that are closely related to pathogenic bacteria, so there’s no risk to people,’ Goswami said. ‘As we expected, our tests showed the system was effective against bacillus subtilis.’

The technology is said to be an improvement over traditional filter-based systems in part because there is no opportunity for bacteria to collect and multiply on the filters that clear it from the air. ‘Filters can actually increase the danger because they concentrate the bacteria,’ said Goswami. The system is also an improvement over systems that use ultraviolet light, which do not consistently kill all the bacteria, he added.

Goswami said the technology could be installed cheaply in central ventilation systems to decontaminate buildings or homes or used in specific locations where contamination is feared.