The World Health Organization (WHO) has linked poor IAQ and the inhalation of certain pollutants to a range of cardiovascular and respiratory ailments, including cancer. Tackling this issue, particularly in Asia, has become an issue of paramount importance.

Prompted by the country’s severe smoke haze, the National University of Singapore (NUS) has developed a low-tech, low-cost but very effective solution to the issue of poor air quality.

The region has been particularly affected due to numerous forest fires in the region over the last few years, largely caused by open burning to clear land and forests for agricultural uses in neighbouring Malaysia and Indonesia.

It can be made worse during moderately dry seasons when prevailing winds blow haze across Singapore, particularly in June to September during the southwestern monsoon season.

“While Singapore tries to solve the cross border political issues of the haze through collaboration and discussion with neighbouring governments, people are left to suffer extremely poor air quality,” said Richard Outhwaite, director of Web Earth, a local environmental and sustainability consultancy.

Singapore measures its air quality based on a count of particulate matter and pollutants. This method is known as the Pollutant Standards Index (PSI).

PSI includes a measure of six pollutants – sulphur dioxide (SO2), particulate matter (PM10) and fine particulate matter (PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO) and ozone (O3).

During recent haze events, the PSI count reached over 400, well into the hazardous range, which is deemed to be anything above 300.

“As a result many people are left with little or no choice except to don the N95 mask throughout their day to day activities,” said Outhwaite.

“A common response for residents is to head for one of the country’s many shopping malls, with the belief that the centralised AC system will provide a better quality of air. However, the current building codes do not require fresh air systems that will filter out all of the PM2.5 fine particulate out of the air, leaving occupants still breathing poor quality air.”

Outhwaite said the retrofitting of higher performance filters, for example MERV 13 or above, is not always so straightforward.

“Additional filters mean more static pressure, needing bigger fans to maintain fresh air flows and increasing capital and operating costs for building owners,” he explained.

However, one of the most innovative solutions to solving the poor IAQ problem is also the simplest.

“Collaboration by the National University of Singapore has developed an easily installable cover for a conventional standing fan that transforms it into an air purifier for as little as $80, and is able to purify a 45 square metre room in one hour,” said Outhwaite.

“This low-tech solution provides people with a cheap and effective system that can be adapted to a common household item, showing that sometimes the simplest solution is the best.”

Associate professor Jeff Obbard from the National University of Singapore’s Department of Civil & Environmental Engineering noted that the breakthrough was a boon to those in high-pollution area.

“In Singapore, we typically spend about 90 per cent of our time indoors, and we have successfully commercialised this research discovery so that everyone can benefit from a cost-efficient way of swiftly and effectively reducing PM2.5 pollutants in indoor air,” he said.

The research team was surprised to discover that air conditioning units did not always provide adequate protection against PM2.5, and could even be a source of PM2.5 if not well maintained.

The NUS filtration system has been specifically designed to fit onto standing, floor and wall fans that are widely used in Singapore and other parts of Asia. The system delivers an optimal airflow to quickly clear the air of PM2.5, and also suppresses new PM2.5 that is constantly being generated. The system is also able to reduce levels of volatile organic compounds (VOCs) that are typically associated with the odour from haze pollution.

140526101652-large“It is important for any system to cover every corner of the room” said Obbard. “We reduce PM2.5 where it matters most – in the air that we breathe, not just at the filter itself.”

The system can be used effectively in both semi-naturally ventilated and air-conditioned spaces and is especially suitable for cost-effective use in hospitals, care homes and community centres.

Another issue facing commercial operators in the tropics is the problem of humidity and mould control.

“In our recently completed cinema project, 321 Clementi, the operator Eng Wah cinemas was constantly battling the humidity and repainting and replacing ceiling panels in its previous development,” said Outhwaite.

High volume spaces with overhead air distribution mean colder air is required to cool the occupants below, and this air creates condensation around the diffusers on the ceiling.


“To overcome this, innovative fabric ducting has been installed to distribute cool air throughout the cinema hall at a lower temperature, avoiding condensation and the time spent repainting the ceilings,” Outhwaite said.