'Can use meh?' What to know about N95 haze face masks expiring in December 2026

As part of its "practical steps" to support Singaporeans who may be more vulnerable to the effects of haze, the Government on Wednesday (Oct 14) announced that it will distribute N95 masks to vulnerable persons.

Those from the Pioneer Generation and Merdeka Generation; holders of the Community Health Assistance Scheme (CHAS) Blue and Orange cards and Medical Fee Exemption Cards (MFEC); and recipients of ComCare Assistance have since been able to collect their masks at community clubs or designated vending machines located at selected public transport hubs, social service offices and People's Association venues.

In addition, pregnant women, children between the ages of seven and 16, and those with medical conditions such as asthma may also collect their masks at community clubs.

But with about 10 per cent of eligible Singaporeans having collected their haze masks, some have taken to social media to point out that the masks are expiring in December 2026.

They have also asked why the Government did not give out masks with a longer window before expiry.

"Can use meh? Already expiring in two months," one user said in a Facebook post, adding that he would have preferred masks that come with a longer shelf life.

Masks are for current haze episode

It has been about six week since the haze began, with the situation worsening over the past two weeks.

During a whole-of-Government press conference on the haze situation on Friday afternoon, Minister for Sustainability and the Environment Grace Fu urged Singaporeans to be prepared for the haze to "persist for some time".

"The situation is fluid. Depending on the weather, we can expect air quality to fluctuate, including the possibility of reaching hazardous level (PSI >300)," the minister said.

But she also pointed out that the situation could improve by end-October or early-November as winds become lighter and more variable during the inter-monsoon period.

By early-December, with the onset of the northeast monsoon, any haze from Sumatra and Kalimantan will blow in the direction away from Singapore, she added.

This means that the N95 masks, intended to support vulnerable Singaporeans through the ongoing haze period, are good through their stated shelf life.

The minister has also stated that the Government will carry out another round of mask distribution, if the need arises.

Why do masks have expiry dates?

Manufacturers do mark their masks with expiry dates.

For example, 3M indicates on its "frequently asked questions" that some of its particulate respirator and surgical mask models have a five-year shelf life when the respirators are stored in their original packaging and under the recommended climate conditions.

And while the manufacturer also states that respirators should be disposed of after the state use-by date, the rationale could lie in the subsequent lines.

"Always inspect the respirator and conduct a seal check before use per the instructions for use. If the person wearing the respirator cannot achieve a proper seal, then the respirator should not be used.

"Even for respirators within the stated shelf life, the respirator should be disposed of immediately upon observation of damaged or missing parts."

This could suggest that the reason behind the expiry date is that mask effectiveness is dependent on having a good fit.

Logically, the elastic bands, nose foam and nose clips could degrade over time, especially if optimum storage conditions are not met.

The reminder on fit was emphasised when AsiaOne spoke to infectious diseases physician Dr Leong Hoe Nam on Friday.

Dr Leong has been directly involved in managing major outbreak situations such as the 2003 Severe Acute Respiratory Syndrome, H1N1 and the more recent Covid-19 pandemic,

He said that users should examine their masks and check for signs of damage, such as frayed edges or holes, prior to use.

"They should then do a seal check by gently exhaling to feel for air leaks around the edges, or inhaling to check whether the mask draws inwards towards their face.

"If there is a leak, users will feel a gush at the site of the leak during exhalation," Dr Leong added.

Dr Pipetius Quah, a respiratory specialist, also took to social media on Friday to share tips on using the N95 mask.

He reiterated at the end of his video that users should conduct a fit check to make sure that there's no leak.

Are masks past their expiry date useless?

In a technical bulletin published in May 2020, 3M said it has often been asked whether respirators can be used beyond their shelf lives.

It reiterated that shelf life and storage conditions are in place to help ensure that all respirator components can effectively contribute to respirators' ability to "seal effectively to the face".

It also referenced two US Centres for Disease Control and Prevention (CDC) studies, which states: "In times of increased demand and decreased supply, consideration can be made to use N95 respirators past their intended shelf life. However, the potential exists that the respirator will not perform to the requirements for which it was certified."

The CDC also published information regarding research conducted by the National Institute of Occupational Safety and Health (NIOSH) on five stockpiled 3M respirator models that are past their shelf life.

In the report titled: Release of stockpiled N95 filtering facepiece respirators beyond the manufacturer-designated shelf life: Considerations for Covid019 response, CDC and NIOSH stated that they believe the listed products, “despite being past their manufacturer-designated shelf life, should provide the expected level of protection to the user".

However, it also said that this is contingent on the basis that stockpile conditions have generally been in accordance with the manufacturer-recommended storage conditions.

In the report, both CDC and NIOSH emphasised that inspection procedures, including conducting user seal checks, should be carried out prior to use.

Meanwhile, an independent study by three doctors on 29 expired N95 respirators — published on the JAMA Internal Medicine Network's journal — found that expired N95 respirators with intact elastic straps and respirators subjected to ethylene oxide and hydrogen peroxide sterilisation had unchanged fitted filtration efficacy of more than 95 per cent.

So, the short answer to the question is, it depends — on the way the masks were stored and whether the mask still properly fits a user.

作为支持可能更容易受到雾霾影响的新加坡人的“实际措施”的一部分，政府于周三（10 月 14 日）宣布将向弱势群体分发 ​​N95 口罩。

建国一代和独立一代人士；持有社区健康援助计划（CHAS）蓝卡和橙卡以及医疗费用豁免卡（MFEC）的人士；以及社区关怀援助计划（ComCare Assistance）的受益人，现在可以在社区俱乐部或指定公共交通枢纽、社会服务办事处和人民协会场所的指定自动售货机领取口罩。

此外，孕妇、7至16岁的儿童以及患有哮喘等疾病的人也可以在社区俱乐部领取口罩。

但由于约有 10% 的符合资格的新加坡人已经领取了他们的防霾口罩，一些人在社交媒体上指出，这些口罩将于 2026 年 12 月过期。

他们还质问政府为什么不发放有效期更长的口罩。

“还能用吗？两个月就过期了，”一位用户在Facebook上发帖说，并补充说他更喜欢保质期更长的口罩。

口罩适用于当前的雾霾天气

雾霾开始至今已有约六周时间，且近两周情况愈发恶化。

周五下午，在政府就雾霾情况举行的新闻发布会上，永续发展及环境部长傅海燕敦促新加坡人做好准备，雾霾可能会“持续一段时间”。

“情况瞬息万变。根据天气情况，空气质量可能会波动，甚至可能达到危险水平（PSI > 300）。”部长说。

但她也指出，到 10 月底或 11 月初，随着季风间歇期风力减弱且变化无常，情况可能会有所改善。

她补充说，到 12 月初，随着东北季风的到来，来自苏门答腊和加里曼丹的任何雾霾都会向远离新加坡的方向吹去。

这意味着，旨在帮助新加坡弱势群体度过持续雾霾期的 N95 口罩，在其规定的保质期内仍然有效。

部长还表示，如有必要，政府将再次进行口罩发放。

为什么口罩会有有效期？

制造商会在口罩上标明有效期。

例如，3M 在其“常见问题解答”中指出，其部分颗粒物呼吸器和外科口罩型号在原包装和推荐的气候条件下储存时，保质期为五年。

虽然制造商也表示呼吸器应在州规定的使用期限后丢弃，但其理由可能在于后面的几行文字中。

“使用前务必按照使用说明检查呼吸器并进行密封性检查。如果佩戴者无法使呼吸器与面部正确密封，则不应使用该呼吸器。”

“即使是仍在有效期内的呼吸器，一旦发现部件损坏或缺失，也应立即丢弃。”

这可能表明，口罩有效期背后的原因是口罩的有效性取决于是否佩戴得当。

从逻辑上讲，松紧带、鼻梁海绵和鼻夹会随着时间的推移而老化，尤其是在没有达到最佳储存条件的情况下。

亚洲新闻网周五采访传染病医生梁浩南博士时，强调了保持健康的重要性。

梁医生曾直接参与应对重大疫情，例如2003年的严重急性呼吸综合征（SARS）、H1N1流感以及最近的新冠肺炎疫情。

他表示，用户在使用口罩前应检查口罩是否有破损迹象，例如边缘磨损或破洞。

“然后，他们应该通过轻轻呼气来检查面罩边缘是否有漏气，或者通过吸气来检查面罩是否向内贴合面部，从而进行密封性检查。

梁医生补充说：“如果发生泄漏，用户在呼气时会感觉到泄漏部位有一股液体涌出。”

呼吸科专家皮佩蒂乌斯·夸赫医生周五也在社交媒体上分享了使用 N95 口罩的技巧。

他在视频结尾重申，用户应该进行贴合度检查，以确保没有泄漏。

过期口罩就没用了吗？

3M 公司在 2020 年 5 月发布的一份技术公告中表示，经常有人问他们呼吸器是否可以在保质期后继续使用。

它重申，已制定保质期和储存条件，以确保所有呼吸器组件都能有效提高呼吸器“有效密封面部”的能力。

报告还引用了美国疾病控制与预防中心（CDC）的两项研究，其中指出：“在需求增加而供应减少的情况下，可以考虑使用超过其预期保质期的N95口罩。但是，这种口罩可能无法达到其认证时所要求的性能。”

美国疾病控制与预防中心 (CDC) 还公布了国家职业安全与健康研究所 (NIOSH) 对五款已过保质期的 3M 库存呼吸器型号进行的研究信息。

在题为《超过制造商指定保质期的库存 N95 过滤式口罩的释放：应对 Covid-19 的考虑因素》的报告中，美国疾病控制与预防中心 (CDC) 和美国国家职业安全与健康研究所 (NIOSH) 表示，他们认为所列产品“尽管已超过制造商指定的保质期，但仍应为用户提供预期的防护水平”。

然而，报告还指出，这取决于库存条件是否总体上符合制造商推荐的储存条件。

报告中，美国疾病控制与预防中心 (CDC) 和美国国家职业安全与健康研究所 (NIOSH) 都强调，在使用前应进行检查程序，包括进行用户密封检查。

与此同时，三位医生对 29 个过期的 N95 口罩进行的一项独立研究（发表在 JAMA 内科医学网络期刊上）发现，弹性带完好的过期 N95 口罩以及经过环氧乙烷和过氧化氢消毒的口罩，其贴合过滤效率仍保持在 95% 以上。

所以，这个问题的简短回答是，这取决于口罩的存放方式以及口罩是否仍然适合佩戴者。