What's Really in Your Indoor Air - And Why It Matters

What's Really in Your Indoor Air - And Why It Matters

The air inside your home or office may be more harmful than you think. Here’s what could be lurking in it.

In some Singapore homes, where air-conditioning runs year-round and windows stay shut, indoor pollutants have nowhere to go. Without natural ventilation, everyday products ranging from air fresheners to new furniture may release chemicals that build up in enclosed spaces over time.

The result can show up in ways that are easy to dismiss: headaches you wake up with, fatigue that sleep does not fix, and a child whose nose will not stop running. These are not always signs of stress or illness. Sometimes, the answer could be in the air itself.

Understanding what is in the air around you is a good place to start!

1. What you are breathing

According to Dr Wong Shiu Hong, Senior Consultant, Department of Occupational Medicine, Sengkang General Hospital, poor indoor air quality (IAQ) is more common than many realise. He shares that most frequently encountered indoor air pollutants fall into three categories: fragrances, volatile organic compounds (VOCs), and smoke.

Fragrances

Air fresheners, reed diffusers, scented cleaning sprays, and perfumes are fixtures in many homes. What they have in common is the release of chemical compounds into the air. In an open or well-ventilated space, these compounds disperse quickly. In an enclosed room, they accumulate. For people with asthma or allergic rhinitis, the build-up may trigger persistent irritation.

Volatile Organic Compounds (VOCs)

When a flat is freshly renovated, the laminates, adhesives, and carpentry used may release VOCs (volatile organic compounds) which are carbon-based chemicals that evaporate easily at room temperature. Formaldehyde is a common VOC found in furniture and finishes. In sensitive individuals, formaldehyde can trigger airway and skin irritation. It is also classified as a Group 1 carcinogen by the World Health Organization.

Some newly renovated flats recorded formaldehyde at 0.72 ppm, more than nine times the recommended safety guideline of 0.08 ppm. Families who have moved into new flats often may not connect the months of headaches and fatigue to the cabinets just installed.

Indoor smoke

Burning incense is a common practice, whether at home altars or during festivals like Qing Ming and the Hungry Ghost Festival. Like candles and cigarettes, burning incense indoors releases fine particles (PM2.5), carbon monoxide, and VOCs into the air.      

A Singapore Chinese Health Study found that long-term incense use was associated with a 12% higher risk of fatal cardiovascular disease. The practice does not have to stop but opening a window to improve air circulation when burning makes a big difference.

Each of these three compounds is largely invisible and undetectable at low levels, so it is easy to assume the air is clean.

These days, more homes and workplaces are engaging vendors that offer Indoor Air Quality (IAQ) assessments to evaluate the air quality in their living and working spaces, but a passing result may not always tell the full story.

2. What IAQ results are not telling you

Singapore's benchmark for indoor environments is the Singapore Standard Code of Practice SS 554 which sets limits for common indoor pollutants, including carbon monoxide, formaldehyde, and fine particles. But it does not cover fragrances, and it is designed for the general population, not for individuals with respiratory sensitivities.

A room’s air can test within limits on a quiet morning and tell a different story by Friday afternoon, after a week of cleaning sprays and sealed windows. Dr Wong adds that occupant feedback often picks up patterns that instrument readings alone will miss.

Slow build-up is the real danger

A single exposure to fragrance or smoke is rarely the concern. The risk is repeated, low-level exposure that builds up in a space that does not receive enough fresh air.

"Poor ventilation allows pollutants to accumulate," says Dr Wong. "When taking a taxi at times, you might notice a lingering cigarette smell with the windows down. If the driver regularly smokes in the taxi, that accumulation over time may become a health risk."

3. When your home or office is making you sick

Some symptoms are easy to explain away, until you notice that they follow a pattern.

What Sick Building Syndrome looks like

Persistent headaches, fatigue, or a cough at work that disappears over the weekend. It is to blame them on stress or a busy week. But if several people in the same space share the same complaints and feel better once they leave, the indoor environment itself could be a likely cause. This is called Sick Building Syndrome (SBS) which affects nearly 1 in 5 office workers, according to a Singapore study of 2,856 workers across 56 buildings.

Signs that point to your environment

Watch out for these signs that your indoor environment may be the cause:

● Symptoms affecting multiple people in the same space
● Odours that linger for hours
● Poor airflow
● Symptoms that begin after renovation, new furniture, or cleaning

Using multiple chemical products together and poor ventilation are already a concern – heat compounds this further by causing chemicals to evaporate faster, releasing more particles into the air. The clearest signal is when symptoms follow a consistent pattern tied to a specific space or activity.

4. The people most affected

Indoor air quality affects everyone, but some people feel it sooner and more severely. Dr Wong identifies five groups that are more sensitive to indoor pollutants:

● People with asthma or allergic rhinitis
● People with chronic lung conditions, such as Chronic Obstructive Pulmonary Disease (COPD)
● People prone to migraines or sensitive to chemical scents
● Children
● Older adults

The numbers in Singapore make this particularly relevant. Allergic rhinitis affects up to 48% of school-aged children and asthma exceeds 20% at all ages. Most households include at least one person in a more sensitive group.

In addition, children breathe faster relative to their body weight, while older adults may have less resilient lungs due to age or sickness. Both groups can develop symptoms when experiencing pollutant levels that a healthy adult in the same room tolerates without issue.

In offices, if complaints about headaches or fatigue cluster around the same floor, the same hours, or days when the space is poorly ventilated, air quality is worth investigating before attributing to stress.

If symptoms persist or affect several people in the same space, the priority is finding the source, not just managing the symptoms. Doing an IAQ assessment is a good starting point. From there, one can consult SKH's Department of Occupational Medicine to address the IAQ findings and advise the next steps. This service is accessible via a GP referral through the GPFirst programme.