Urban health: improving our indoor ecosystems

4 November 2016

Dr Lai Ka Man (Croucher Scholarship 1998 and Croucher Fellowship 2001) is an environmental microbiologist and Associate Professor of Biology at Hong Kong Baptist University (HKBU) where she first studied as an undergraduate.

Lai grew up on a Hong Kong public housing estate and was the only one of five siblings to enter university.

“My father was a very adventurous person. We had no money for Disneyland or overseas trips so he would take me walking in the countryside and along the shorelines on public holidays. I saw plants and just wondered how they grew,” she says, and it was that natural curiosity that led to her study Biology at HKBU.

Chemicals in our water

In her final year undergraduate project, she examined the possibility of using fly ash from local power plants for lime stabilisation of wastewater sludge, and the final product was tested as an agricultural fertiliser. It set a trend for her future academic career and during her Master’s degree at Chinese University Hong Kong (CUHK) she isolated a fungus, Geotrichum candidum, that could degrade azo dyes used in local textile factories, which were polluting local waterways.

Lai had never travelled beyond Mainland China but on completion of her Master’s degree, she was awarded a Croucher Scholarship to undertake PhD studies at Imperial College London on wetlands. Instead, on arrival, her supervisor advised her to change subject to endocrine disrupting substances; pollutants that cause disruption to the hormonal system.

Scientific research should be about enhancing society.

It was a hot topic, particularly in London, where drinking water was sourced from the River Thames where these substances were thought to have entered the river via the wastewater system.

“At that time, we had little knowledge about these substances. Even after my PhD, I was still publishing papers with the Imperial team about this topic,” she says.

Lai looked at the partition of the chemical in sediment columns. Whether it stayed in the water column or bound to the sediment was very important to understanding its environmental fate and behaviour. In 2006 she published the first paper at Imperial College on the binding of waterborne steroid estrogens in river and estuary systems.

“We knew wastewater treatment work couldn’t remove 100% of pollutants and that the chemicals in female contraceptive pills were very resistant to degradation, but there was an assumption that they would be naturally diluted in the river system,” she says and subsequently several hundreds of these chemicals are now listed by EU as potential endocrine disruptors.

In 2002, on completion of her PhD , she was awarded a Croucher Fellowship to undertake post-doctoral research at the School of Public Health at Harvard University. Instead of studying mould, which was her intention, there was widespread concern about the threat of bio-terrorism, post 9/11, and the possibility of an airborne smallpox virus being released. So in addition to being trained by world class mycologists at Harvard, Lai also started studying airborne micro-organisms and how they could be destroyed with germicidal UV lighting.

“My project was very popular and I also started doing high level consultancy work for corporations like Toshiba and Sharp which built up my confidence,” she says and thinks it is no bad thing to see the commercial value of research and not just the intellectual value.

“Scientific research should be about enhancing society,” she says.

In 2005 Lai was appointed as Lecturer in Environmental Health and Engineering at the Department of Civil, Environmental and Geomatic Engineering at University College London (UCL) where she undertook projects including the microbial risk in residential buildings due to flooding, building toilets after natural disasters, and TB transmission in offices.

“One of the best things I did at UCL was to found a research centre called the Healthy Infrastructure Research Centre funded by the UK Engineering and Physical Sciences Research Council,” she says.

The funding support for the new centre was over £1 million and Lai designed the laboratory with an environmentally controlled chamber which allows bioaerosol research to be conducted in a room size environment.

Airborne pathogens

She returned to Hong Kong in 2012 to take up her current position at HKBU where she undertook consultancy work for Dyson to test the efficiency of air cleaning machines in removing airborne viruses. In 2014 her research with the World Green Organisation into the health risks of living in tiny subdivided apartments, revealed air bacterial counts six-times higher than the official ‘clean air’ level. The study was widely reported in the local media; domestic public health risks are a common theme in her work.

“Cockroaches carry germs and release allergens and endotoxins in their faeces,” she says and explains that in her recent study there are four different species of cockroach sampled at homes in Hong Kong and each one has a different bacterial profile. This finding helps to understand the habitat of these cockroaches and explain the different levels of pathogens carried by the cockroaches and endotoxins released in the faeces.

She also believes it is an important part of her job to be a neutral expert who can test if commercial products are working as advertised.

“People with low incomes will spend their last few dollars for the benefit of their children’s health so it is important to establish if these products have any real benefit,” she says and recalls how she tested a HK$40 antiseptic badge which claimed to kill airborne germs in the immediate vicinity of the wearer, only to find it had no measurable value at all.

Her current research topics include studying the source of foul odours from office air conditioning plants and looking at genetic responses of airborne bacteria to changes in temperature and relative humidity. She is also working on mould.

“My research is very much applied to daily life and the wellbeing of disadvantaged people,” she says.

Dr Lai Ka Man is Associate Professor of Biology at Hong Kong Baptist University (HKBU). After graduating in Biology from HKBU and completing a Masters Degree at Chinese University Hong Kong (CUHK), she was awarded a Croucher Scholarship in 1998 to undertake a PhD at Imperial College London. In 2001 she was awarded a Croucher Fellowship to study at the School of Public Health at Harvard University . Her pioneering work into countering airborne viruses led to a number of high level consultancy appointments. In 2005 she joined University College London as a Lecturer, and in 2010 was promoted to Senior Lecturer in Environmental Health Engineering at the Department of Civil, Environmental and Geomatic Engineering. She returned to HKBU from London in 2012 to take up her current role and her research topics include the generic responses of airborne viruses to changes in temperature and relative humidity. 

To view Lai’s personal Croucher profile, please click here.