N95 or KN95 During Haze: Wear It Right, Replace It at the Right Time

Alpro pharmacist explains proper respirator fit, when it should be replaced, and the extra precautions needed during pregnancy or with heart and lung conditions

When the haze rolls in, a familiar scene plays out in every Malaysian household: someone digs out a box of N95 or KN95 masks, hands them around, and everyone heads out the door assuming the job is done.

But a respirator like this isn't really a "put it on and forget it" tool. 𝙒𝙤𝙧𝙣 𝙩𝙝𝙚 𝙬𝙧𝙤𝙣𝙜 𝙬𝙖𝙮, it protects far less than most of us assume. And for a few groups e.g. pregnant women and children especially, it may not even be the right tool to reach for.

Let's clear up what actually matters.

Not All Masks Are Equal

Haze is made up of very fine particles, small enough to slip straight past a loose surgical mask. A properly fitted N95 is designed to filter at least 95% of test particles around the size that is hardest for the filter to capture, which means it can substantially reduce exposure to fine haze particles, including PM2.5. That's exactly why health authorities point to a 𝘄𝗲𝗹𝗹-𝗳𝗶𝘁𝘁𝗲𝗱 𝗿𝗲𝘀𝗽𝗶𝗿𝗮𝘁𝗼𝗿 𝗼𝘃𝗲𝗿 𝗮𝗻 𝗼𝗿𝗱𝗶𝗻𝗮𝗿𝘆 𝘀𝘂𝗿𝗴𝗶𝗰𝗮𝗹 𝗺𝗮𝘀𝗸 𝘄𝗵𝗲𝗻 𝘁𝗵𝗲 𝗮𝗶𝗿 𝗼𝘂𝘁𝘀𝗶𝗱𝗲 𝘁𝘂𝗿𝗻𝘀 𝗵𝗮𝘇𝘆.

KN95 respirators are manufactured to China's GB 2626 standard and are designed to achieve at least 95% particle-filtration efficiency under specified test conditions. A genuine, compliant KN95 may be a reasonable alternative, but performance also depends heavily on fit. Many KN95 models use ear loops, which may not seal as reliably as the two headbands commonly used by N95 respirators. 

"𝗪𝗲𝗹𝗹-𝗳𝗶𝘁𝘁𝗲𝗱" is 𝘁𝗵𝗲 𝗸𝗲𝘆 𝘄𝗼𝗿𝗱𝘀 𝗵𝗲𝗿𝗲. 𝗔 𝗿𝗲𝘀𝗽𝗶𝗿𝗮𝘁𝗼𝗿 𝗼𝗻𝗹𝘆 𝗽𝗿𝗼𝘁𝗲𝗰𝘁𝘀 YOU 𝗮𝘀 𝘄𝗲𝗹𝗹 𝗮𝘀 𝗶𝘁𝘀 𝘀𝗲𝗮𝗹.

Check The Seal, Not Just The Box

The mask should sit snugly across the nose, cheeks and chin, with no gaps for air to sneak in around the edges, true for both N95 and KN95.

Here's the part that catches a lot of people out: facial hair, jewellery or eyewear sitting under the sealing edge can break that seal and let unfiltered air leak straight in. If there's a gap anywhere, the respirator underneath it is doing a lot less than you'd hope.

How Long Can You Actually Wear It?

This is where a lot of misinformation floats around. Some claims that an N95 or KN95 is "only safe for one hour," or that outdoor trips must be capped at exactly 30 to 40 minutes. There is no universal time limit. How long a respirator can be worn comfortably depends on the wearer, activity level, environmental conditions and fit. If it becomes uncomfortable or difficult to breathe through, move to cleaner indoor air and remove it safely.

What's actually useful to know instead: replace the respirator when its condition changes, when it becomes wet, dirty, damaged, misshapen, hard to breathe through, or no longer seals properly. 

Never wash, heat or attempt to disinfect a disposable N95 or KN95 at home, these methods may damage the respirator, affect its filtration performance, or reduce its ability to seal properly.

If the mask starts to feel uncomfortable, the right move is to head indoors to cleaner air before taking it off, not to pull it down in the middle of a smoky street.

𝗢𝗻𝗲 𝗺𝗼𝗿𝗲 𝗺𝘆𝘁𝗵 worth putting to rest: wearing a well-sealed respirator does increase the effort of breathing, and some people do feel discomfort, tiredness or a mild headache because of that added resistance. 

Although respirators can increase breathing effort and discomfort, current evidence does not support the claim that normal use causes dangerous CO2 poisoning in healthy adults.

Pregnant Women: Additional Precautions Are Needed

According to Ministry of Health Malaysia haze guidance, 𝐍𝟗𝟓 𝐫𝐞𝐬𝐩𝐢𝐫𝐚𝐭𝐨𝐫𝐬 𝐚𝐫𝐞 𝐧𝐨𝐭 𝐜𝐨𝐧𝐬𝐢𝐝𝐞𝐫𝐞𝐝 𝐬𝐮𝐢𝐭𝐚𝐛𝐥𝐞 𝐟𝐨𝐫 𝐩𝐫𝐞𝐠𝐧𝐚𝐧𝐭 𝐰𝐨𝐦𝐞𝐧. Since other tight-fitting respirators such as KN95 may also increase breathing effort, pregnant women should prioritise avoiding haze exposure and consult their doctor before using one.

For pregnant women, the priority isn't really "which mask", it's "how to avoid needing one" in the first place. 

That means staying indoors with cleaner air, and skipping outdoor trips that aren't necessary while the haze is heavy. If getting outdoors genuinely can't be avoided, the safest bet is to check with your doctor about what suits your own circumstances. MOH guidance also states that N95 respirators are unsuitable for children, an adult-sized respirator may not seal properly on a child's face, so keeping children indoors during heavy haze matters just as much.

Asthma, COPD, And Heart Or Lung Conditions

If you're managing asthma, COPD, or a heart or lung condition, haze season calls for a bit of a strategy shift too:

• Reduce outdoor exposure first. Keep doors and windows closed when appropriate, and use an air purifier indoors if you have one.
• Keep your treatment close by. Continue medication as prescribed, carry a reliever inhaler if one has been prescribed, and follow your asthma action plan if you have one.
• Respond early to warning signs. If wheezing, dizziness, chest tightness or unusual shortness of breath develops, move immediately to cleaner indoor air and remove the respirator once safe. Seek urgent medical attention if symptoms are severe, worsening, or do not improve.

Myth Vs Fact: N95/KN95 During Haze

Quick Recap For Haze Season

• Check the seal every time: facial hair, jewellery, eyewear and gaps reduce protection.
• Replace by condition, not by the clock and never wash, heat or disinfect an N95 or KN95 at home.
• If it becomes uncomfortable, move to clean indoor air before removing it.
• Pregnant women and children: staying indoors comes first; speak to your doctor if outdoor exposure can't be avoided.
• Asthma, COPD, heart or lung conditions: keep your medication and action plan ready, and respond early, don't wait out severe symptoms.

Unsure what's appropriate for your own health condition, age, or stage of pregnancy this haze season?

Our pharmacists at Alpro Pharmacy are always happy to talk it through with you.

References

1. Centers for Disease Control and Prevention. (2025, March 12). How to use your N95 respirator. U.S. Department of Health and Human Services. Retrieved September 1, 2026, from https://www.cdc.gov/niosh/ppe/php/n95-use/index.html
2. Ministry of Health Malaysia. (n.d.). Usage of personal protection during haze. Retrieved September 1, 2026, from https://www.moh.gov.my/en/core/health-information/jerebu/artikel-dan-panduan-pengguna-berkaitan-jerebu/usage-of-personal-protection-during-haze
3. Nassri, M., Barari, P., Khanizadeh, M., Faridi, S., Shamsipour, M., Naddafi, K., Niazi, S., & Hassanvand, M. S. (2024). The influence of N95 and surgical masks on carbon dioxide levels: A comprehensive systematic review and meta-analysis. Heliyon, 10(16), e36626. https://doi.org/10.1016/j.heliyon.2024.e36626