Singaporeans were snapping up air purifiers over the weekend as PSI readings remained in the "moderate" range.
Major electronics stores reported spikes in sales with some running out of popular models - such as those which are high-efficiency particulate absorption, or Hepa- certified.
Ms Jacqueline Au, 42, tried to buy a Honeywell air purifier at Best Denki VivoCity last Saturday, only to be told that the store was out of stock.
"They only have a high-end model from Sharp at the VivoCity store," she said, adding that it cost $1,200 - twice what she was prepared to pay for a mid-range model. "Maybe I'll look online or in other stores."
Last Friday night, PSI readings hit a high of 71 for the year, with many Singaporeans complaining about the lingering smell of burning wood.
Yesterday, the three-hour PSI reading was a moderate 56 at 9pm. Unhealthy readings were reported in several areas in Malaysia.
Retailers said many Singaporeans are preparing for the haze to continue. Courts has seen air purifier sales triple from January till now, compared to the same time last year.
"Best-selling models are running low," said a spokesman, who anticipated similar sales spikes for air-conditioners, coolers and fans. "We are in close discussion with suppliers to replenish stock as fast as we can."
At Gain City, air purifier sales have more than doubled since Environment Minister Vivian Balakrishnan warned about the possible worsening of the haze on his Facebook page on Feb 11.
Models from popular brands such as Honeywell, Blueair and LG have sold out, though the electronics store still has some from brands like Sharp and Hitachi which are Hepa-certified.
Hepa purifiers have strong filters which trap particles as small as 0.3 micrometre within fine meshes of fibreglass filters. Such purifiers are also being sold online at Amazon and qoo10.sg.
Best Denki, which sells purifiers costing from $149 to $1,299, said much of its stock from brands like Honeywell, Panasonic and Europace has run out, but "small pockets" remained at some outlets.
Massmark International, the sole distributor of Honeywell and Blueair air purifiers, said it recently ran out of stock for these brands. Stocks are expected to come in next month, it added.
While demand for air purifiers has risen, stores say it is nowhere near last year's demand when PSI readings hit a record high of 401 in June.
Harvey Norman said that it has "sufficient stock" to meet impending demand.
Other stores are ordering hundreds more purifiers from suppliers after struggling to meet demand last year.
Best Denki is ordering up to 70 per cent more stock while Gain City is tripling its orders to suppliers.
Earlier last week, the Government gave the assurance that it has 16 million N95 masks in its stockpile, in addition to the 280,000 available in major retailers' inventories.
Yio Chu Kang resident Ben Wee, 23, said: "It's time to take out the haze gear from the storeroom now, but we should be more prepared this time around."
Additional reporting by Kenny Chee