SINGAPORE: There is currently no data – both locally or internationally – that looks into the long-term health impact of transboundary haze, Minister of State for Health Lam Pin Min said in Parliament on Friday (Jan 29).

Any research on this would be “highly challenging” as results would be based on observational studies, which would not be able to show a definite cause-and-effect relationship, Dr Lam said in response to a question by Non-Constituency Member of Parliament (NCMP) Leon Perera.

“For example, it would be difficult to determine that intermittent exposure to haze 20 years ago caused the chronic obstructive airways disease in a person, since it could also have been caused by other factors such as smoking, previous lung infection, or existing lung diseases,” Dr Lam said.

However, there have been overseas studies based on long-term exposure to haze – different from the short-term, episodic haze that Singapore experiences, he said.

“These studies show that continuous, long-term exposure to air pollutants over several years may result in lung function abnormalities in children and subsequently, in adulthood. This could lead to greater susceptibility to the effects of ageing, infection and other pollutants, such as tobacco smoke, in adults.”

Short-term exposure to haze may cause irritation of the eyes, nose and throat, although such irritation usually resolves on its own, Dr Lam noted. In individuals with pre-existing chronic heart or lung diseases, short term exposure may trigger an episode or exacerbate the underlying diseases, such as an asthma attack, he added.

Several measures have been put in place to help Singaporeans in times of haze, such as distributing care packs and masks to the needy and implementing the Haze Subsidy Scheme, which provided subsidies of S$3.3 million last year with more than 77,000 haze-related attendances. Air purifiers will also be installed in classrooms of schools by July, Dr Lam said.