Air-conds not so cool after all

PETALING JAYA: It was partly cloudy but the mercury still registered a high 33ºC.

That was the temperature recorded here yesterday.

So for most urbanites, refuge from the heat comes from air-conditioned places. And barely anyone drives a car without air-condition these days.

Air-conditioners have become such a huge part in people’s lives that there is little discussion about the downside of extended usage.

But it has now been suggested that prolonged usage could cause problems – from drowsiness to affecting a person’s concentration due to high carbon dioxide (CO2) levels.

“I have measured CO2 levels in my car while driving from USJ (Subang Jaya) to Mid Valley. The CO2 levels exceeded 2,500 parts per million (ppm) for a 35-minute drive.

“So, I would expect the CO2 levels in bedrooms to be high in the morning, if all windows are closed, ” the Malaysian chapter of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (Ashrae) former president Leong Siew Meng (pic) said.

Under the Industry Code of Practice on Indoor Air Quality 2010 issued by the Department of Occupational Safety and Health, the ceiling limit for CO2 was at 1,000ppm for healthy indoor air quality (IAQ).

Poor IAQ levels have been linked to short-term and long-term problems ranging from allergic reactions, respiratory problems and eye irritation to sinusitis and bronchitis.

A research paper published by the Nature Sustainability journal, titled “Direct Human Health Risks of Increased Atmospheric Carbon Dioxide”, also suggested that even with a level as low as 1,000 ppm, CO2 levels have the potential to pose health problems despite exposure to it lasting only a few hours.

The journal noted that the health risks from high CO2 levels include inflammation, reduced higher-level cognitive abilities, bone demineralisation, kidney calcification and oxidative stress.

“High CO2 levels in cars also have the potential to cause drowsiness, ” Leong said.

He noted that some households would install fixed windows, which meant that they could not be opened.

With fixed windows, Leong said CO2 levels would build up in the enclosed space as many households used split-unit air-conditioners that do not bring outdoor air in.

“Those who are asthmatic and sleep with air-conditioning turned on overnight will worsen their condition, ” he said.

As a solution to sleeping in an air-conditioned room, Leong suggested that one should leave a small gap of between one to two centimetres in a window for infiltration of outdoor air.

For occupants who rely on an intake of outdoor air, he suggested installing a small exhaust fan in the room.

“As a solution for long-distance driving, latch open the vehicle louvre occasionally to bring in outdoor air to overcome the build-up of carbon dioxide concentrations (when outdoor air is not polluted by heavy vehicles in front or open burning in the surroundings)”, he said.

Ashrae president Ng Wen Bin said worsening asthma problems, allergies as well as sick building syndrome were health issues that could result from contaminated air conditioning units.

“This sick building syndrome is associated with symptoms such as nasal congestion, difficulty breathing, headache, fatigue, and skin irritation.

“There may be some microorganisms growing in the air conditioning system as the process of cooling warm air generates a lot of moisture and condensation, which must be discharged.

“So, if your air conditioner does a bad job of this, whether due to poor maintenance, damage or careless design, it can become a breeding ground for bacteria and fungi, ” he said.

Ng said to better protect one’s health, the best defence is a well-maintained and routinely serviced air conditioning unit.

The Nature Sustainability journal noted that environmental exposure to CO2 should also be viewed from the perspective of vulnerable groups – infants, the elderly and weak, and high-exposure groups such as populations residing in urban CO2 domes and in tropical climates.

A September 2019 report published by Ashrae titled “Do Indoor CO2 Levels Directly Affect Perceived Air Quality, Health, or Work Performance?” found that several studies had provided “strong evidence” of reductions in cognitive performance due to increased levels of CO2.

However, the study acknowledged that the results were not consistent with other studies which found that there were “no effects” in the reduction in cognitive performance, adding that none could be found either on acute health symptoms and perceived air quality of CO2 below 5,000ppm.