| Aspect | N95 | Kn95 |
|---|---|---|
| Definition | US NIOSH-approved filtering facepiece respirator that meets 42 CFR Part 84 standards. | Chinese standard GB2626-2006/2019 respirator, similar in function but not US-certified. |
| Purpose | Protects wearer from airborne particles, including droplets and aerosols, in healthcare settings. | Designed for industrial and general particulate protection; widely used during COVID-19 pandemic. |
| Core Mechanism | Uses electrostatic non-woven polypropylene filter layers to capture at least 95% of 0.3-micron particles. | Relies on melt-blown fabric with electrostatic charge; filtration efficiency tested against sodium chloride aerosol. |
| Filtration Standard | Must capture ≥95% of 0.3 µm particles in NIOSH TCL test using charge-neutralized NaCl. | Requires ≥95% filtration of 0.3 µm particles per Chinese standard, using similar NaCl aerosol test. |
| Regulatory Body | National Institute for Occupational Safety and Health (NIOSH) in the United States. | Standardization Administration of China; no direct US federal oversight unless imported. |
| Fluid Resistance | Many N95s are cleared by FDA as surgical masks, offering ASTM F1862 fluid resistance. | Standard KN95s lack fluid resistance; surgical KN95s must meet separate Chinese YY0469 standard. |
| Fit Testing | Requires mandatory quantitative or qualitative fit testing in US occupational settings. | No mandatory fit test in China; users rely on self-check for seal adequacy. |
| Headband Style | Typically uses two elastic headbands that go around the crown and neck. | Usually features ear loops, which may create a looser facial seal. |
| Seal Quality | Headbands provide stronger, more consistent seal across varied face shapes. | Ear loops often cause gaps; some models add adjustable clips to improve tension. |
| Breathing Resistance | Max inhalation resistance ≤343 Pa and exhalation ≤245 Pa per NIOSH at 85 L/min. | Inhalation resistance ≤350 Pa and exhalation ≤250 Pa per GB2626 at 85 L/min. |
| Bacterial Filtration | FDA-cleared surgical N95s show BFE ≥95% against 3-micron Staphylococcus aureus. | Standard KN95s do not test BFE; surgical versions report BFE ≥95% per YY0469. |
| Particle Capture | Filters 95% of 0.3 µm particles; higher efficiency for larger and smaller sizes. | Filters 95% of 0.3 µm particles; similar efficiency curve but no NIOSH verification. |
| User Population | Healthcare workers, first responders, and industrial workers in US-regulated workplaces. | General public in China, Asian markets, and during pandemic surges as an alternative. |
| Quality Control | NIOSH audits manufacturing plants, requires quality assurance, and conducts random testing. | China's certification involves type testing; production QA varies by manufacturer. |
| Labeling | Marked with "NIOSH" and "N95" approval number, e.g., TC-84A-XXXX. | Marked with "GB2626-2006" or "GB2626-2019" and "KN95" on the facepiece. |
| Counterfeit Risk | NIOSH maintains a list of approved models; unapproved units are easily identified. | High counterfeit prevalence, especially during 2020; many fake KN95s failed filtration tests. |
| Cost Range | Priced roughly $1–$3 per unit in bulk; surgical versions cost slightly more. | Typically $0.50–$1.50 per unit in bulk; prices surged during pandemic shortages. |
| Availability | Widely stocked in US medical supply chains; occasionally restricted during shortages. | Abundant in Asian markets; imported into US under EUA during COVID-19 emergency. |
| Exhalation Valve | Some N95s have valves for easier breathing; surgical N95s are valve-free. | Most KN95s are valve-free; valved versions exist but are less common. |
| FDA Clearance | Surgical N95s are FDA-cleared under 510(k) as Class II medical devices. | KN95s are not FDA-cleared; they required Emergency Use Authorization (EUA) for US use. |
| Lifespan | Single-use; NIOSH recommends discarding after each patient encounter or if soiled. | Single-use; no official reuse guidance; discard when damaged, wet, or contaminated. |
| Storage Stability | Maintains filtration for up to 5 years if stored in original packaging, dry, and cool. | Similar stability; Chinese standards suggest 3–5 years shelf life under proper conditions. |
| Decontamination | UV, heat (70°C), or vaporized H2O2 can be used in crisis; efficacy varies by model. | Not officially recommended; limited studies show UV or dry heat may preserve filtration. |
| Face Seal Test | NIOSH requires user seal check (positive/negative pressure) before each use. | Users perform a self-seal check; no standardized protocol exists in GB2626. |
| Particle Size Test | NIOSH uses 0.3 µm NaCl particles at 85 L/min flow rate for certification. | GB2626 uses 0.3 µm NaCl particles at 85 L/min; test method is nearly identical. |
| Ear Loop Tension | Not applicable; N95s use headbands, not ear loops. | Ear loop tension varies widely; poor tension reduces seal and protection. |
| Nose Wire | Metal nose clip is adjustable; foam padding often improves comfort and seal. | Most have a metal nose strip; some lack foam, leading to bridge pressure or leaks. |
| Intended Environment | Healthcare settings (hospitals, clinics) and OSHA-regulated industrial sites. | General public use, low-risk workplaces, and community settings in Asia. |
| Best-Fit Scenario | Choose N95 for high-risk medical procedures, fit-tested workers, and US regulatory compliance. | Choose KN95 for everyday public use, travel, or when N95s are unavailable and fit is acceptable. |
N95 is a filtering facepiece respirator certified by the U.S. National Institute for Occupational Safety and Health (NIOSH). It blocks at least 95% of airborne particles, including viruses and dust, when fitted properly. N95 respirators exist to protect healthcare workers and the public from respiratory hazards.
An N95 respirator is a tight-fitting, NIOSH-approved particulate filtering device that removes at least 95% of airborne particles larger than 0.3 microns. Unlike surgical masks, N95 forms a seal against the face, reducing both inhaled and exhaled particle leakage. It is non-oil resistant, meaning it fails against oil-based aerosols.
| Characteristic | What It Means in Practice |
|---|---|
| Filtration efficiency | Blocks at least 95% of 0.3-micron particles under NIOSH test conditions, including droplets and aerosols. |
| Fit seal | Requires a tight facial seal; any gap reduces protection by up to 50% or more, so fit testing is mandatory. |
| Breathing resistance | Creates noticeable airflow resistance; users often feel warmth and effort when inhaling, which can cause fatigue. |
| Fluid resistance | Most N95 models are fluid-resistant but not fully waterproof; prolonged exposure to blood or moisture degrades fibers. |
| Reusability limit | Designed for single-use; reuse is discouraged after 8 hours or if soiled, wet, or deformed. |
| Valve option | Valved N95 reduces exhalation resistance but releases unfiltered exhaled air, unsuitable for source control in surgery. |
| NIOSH approval | Each model must pass strict certification; look for the "NIOSH Approved" label and TC-84A-xxxx number. |
| Headband design | Uses two head straps instead of ear loops, ensuring a more secure and adjustable fit across varied face sizes. |
| Particle size range | Effective against 0.3-micron particles, but actually filters smaller and larger particles with higher efficiency. |
| Decontamination limits | UV, heat, or vaporized hydrogen peroxide can extend use, but improper methods destroy electrostatic charge and filtration. |
| Advantages | Limitations |
|---|---|
| Filters at least 95% of airborne particles, including viruses, bacteria, and fine dust, providing high-level respiratory protection. | Requires formal fit testing; a poor seal reduces protection dramatically, and many users fail the fit test on first try. |
| NIOSH certification ensures rigorous quality and performance standards, unlike cloth masks or unregulated respirators. | Breathing resistance is significantly higher than surgical masks, causing discomfort, headaches, or dizziness during extended use. |
| Forms a tight facial seal that prevents both inward and outward leakage, protecting the wearer and others when unvalved. | Cannot be used in oil-mist environments, such as machining or spraying paints, because oil degrades the filter media. |
| Available in multiple styles (cup, flat-fold, duckbill) to accommodate different face shapes and user preferences. | Single-use design creates substantial plastic and fiber waste; disposal costs and environmental impact are major concerns. |
| Effective against 0.3-micron particles, but performance improves for larger droplets and smaller nanoparticles due to diffusion. | Prolonged wear can cause skin irritation, pressure sores, and contact dermatitis on the nose, cheeks, or ears. |
| Valved models reduce exhalation resistance, making physical exertion easier for industrial workers and athletes. | Valved N95 respirators do not filter exhaled air, so they are prohibited in surgical settings where sterile fields are required. |
| Can be decontaminated with UV light or hydrogen peroxide vapor for emergency reuse, extending limited supplies. | Repeated decontamination cycles degrade elastic headbands and electrostatic charge, reducing filtration efficiency over time. |
| Provides dual protection as both a respirator and a fluid barrier, making it suitable for aerosol-generating medical procedures. | Not designed for children or individuals with facial hair; beards and stubble prevent the required airtight seal. |
| Widely available in healthcare and industrial supply chains, with standardized sizing and compatibility with surgical masks. | Counterfeit N95 respirators are common; without proper NIOSH labels, users may receive ineffective or unsafe products. |
| Offers superior protection against wildfire smoke, particulate pollution, and infectious aerosols compared to cloth or surgical masks. | Cost per unit is higher than standard masks, and bulk purchasing is often required, creating budget burdens for low-resource settings. |
A KN95 respirator is a tight-fitting face mask designed to filter at least 95% of airborne particles. It is manufactured to meet the Chinese standard GB2626-2006. The KN95 provides respiratory protection against dust, droplets, and aerosols in occupational and public settings.
The KN95 is a particulate respirator certified under Chinese standard GB2626-2006, requiring a filtration efficiency of ≥95% for particles sized 0.3 microns. Unlike surgical masks, it forms a sealed fit around the nose and mouth, reducing inward and outward leakage of contaminated air.
| Characteristic | What It Means in Practice |
|---|---|
| Filtration efficiency | Blocks at least 95% of 0.3-micron particles, including virus-laden droplets and fine dust. |
| Fit seal | Requires a tight facial seal via nose clip and ear loops; leakage reduces protection significantly. |
| Breathing resistance | Higher airflow resistance than cloth masks; can cause discomfort during heavy exertion. |
| Fluid resistance | Provides some splash resistance, but not fully waterproof; not rated for surgical use. |
| Bacterial filtration | Often tested for bacterial filtration efficiency, typically exceeding 98% in lab conditions. |
| Layer composition | Usually 4-5 layers: melt-blown filter, spunbond, and non-woven fabric for mechanical and electrostatic capture. |
| Valve option | Some models include an exhalation valve to reduce heat buildup, but unfiltered exhaled air may spread infection. |
| Reusability | Designed for single-use; extended wear beyond 8 hours degrades filtration and fit. |
| Regulatory status | Approved under Chinese standard GB2626; not FDA-cleared for surgical use, but allowed for general public. |
| Ear loop design | Most KN95s use ear loops, which may create a less secure fit than headband-style N95 respirators. |
| Advantages | Limitations |
|---|---|
| High filtration efficiency blocks 95% of 0.3-micron particles, including respiratory aerosols. | Ear loop design often creates a looser facial seal than headband-style respirators, reducing real-world protection. |
| More affordable and widely available than N95 respirators in many global markets. | Not cleared by FDA for surgical use; lacks fluid resistance certification for blood splash. |
| Effective against dust, pollen, and PM2.5 pollution for everyday outdoor activities. | Single-use design generates significant plastic waste; not biodegradable. |
| Lightweight and portable; easy to store in pockets or bags for on-the-go protection. | Breathing resistance increases with humidity and prolonged wear, causing fatigue and headaches. |
| Provides better protection than cloth or surgical masks in crowded indoor settings. | Counterfeit KN95s are common; many fail filtration tests, offering false security. |
| Some models include adjustable nose clips for improved fit around the bridge of the nose. | Not suitable for children under 12 or individuals with facial hair that breaks the seal. |
| Can be worn for up to 8 hours continuously without significant loss of filtration efficiency. | Valved versions allow unfiltered exhaled air, potentially spreading infections to others. |
| Tested under Chinese national standards with clear performance criteria for particle capture. | Lacks standardized fit testing requirements; user fit varies widely across face shapes. |
| Effective barrier against large droplets and splashes from coughing or sneezing. | May cause skin irritation or pressure marks on ears with extended daily use. |
| Provides an affordable option for high-risk environments like hospitals when N95 supplies are scarce. | Performance degrades rapidly if exposed to moisture, oil aerosols, or repeated folding. |
| Shared Aspect | How N95 and Kn95 Are Alike |
|---|---|
| Filtration Efficiency | Both N95 and KN95 respirators filter at least 95% of airborne particles, including aerosols and droplets. |
| Primary Purpose | N95 and KN95 masks serve the same core function: reducing inhalation of hazardous airborne particulates. |
| Regulatory Standard | Both N95 and KN95 masks are tested against stringent particulate filtration standards, although by different agencies. |
| Fluid Resistance | N95 and KN95 respirators both offer resistance to splashes and sprays of blood or other bodily fluids. |
| Electrostatic Charging | Both N95 and KN95 rely on melt-blown polypropylene layers with electrostatic charge to capture particles. |
| Multi-Layer Construction | N95 and KN95 masks both use multiple non-woven fabric layers to achieve their high filtration performance. |
| Nose Wire Adjustment | Both N95 and KN95 respirators include a bendable metal nose strip for a tighter facial seal. |
| Head or Ear Loops | N95 and KN95 masks both come in variants with either headbands or ear loops, depending on manufacturer. |
| Single-Use Design | Both N95 and KN95 are classified as disposable respirators intended for limited, non-reusable wear. |
| Fit Test Requirement | N95 and KN95 both require proper fit testing in occupational settings to ensure adequate seal. |
| Particle Size Capture | Both N95 and KN95 are tested using 0.3 micron particles, the most penetrating particle size. |
| Breathing Resistance | N95 and KN95 masks both have similar inhalation and exhalation resistance limits to ensure user comfort. |
| Healthcare Use | Both N95 and KN95 respirators are widely used in healthcare settings for infection control during outbreaks. |
| Public Health Guidance | N95 and KN95 masks are both recommended by global health authorities for high-risk environments. |
| Supply Chain Role | Both N95 and KN95 played critical roles in personal protective equipment supply during global pandemics. |
| Biocompatibility | N95 and KN95 materials are both tested for skin irritation and are generally safe for prolonged contact. |
| Packaging Sterility | Both N95 and KN95 respirators are typically packaged individually or in bulk, often with sterilization options. |
| User Population | N95 and KN95 masks are both used by healthcare workers, industrial workers, and the general public. |
| Filtration Mechanism | Both N95 and KN95 use mechanical and electrostatic filtration to trap particles, not chemical neutralization. |
| Test Aerosol Type | N95 and KN95 both use sodium chloride (NaCl) aerosol in their certification tests. |
| Filtration Flow Rate | Both N95 and KN95 are tested at a flow rate of 85 liters per minute for filtration efficiency. |
| Exhalation Valve Option | N95 and KN95 masks both come in models with or without exhalation valves for easier breathing. |
| Storage Stability | Both N95 and KN95 respirators have similar shelf life when stored properly, typically 3-5 years. |
| Decontamination Limits | N95 and KN95 both lose filtration efficiency after multiple decontamination cycles, limiting reuse. |
| Training Requirements | Both N95 and KN95 require user training on proper donning, doffing, and seal checks. |
| Certification Marking | N95 and KN95 both display certification marks (NIOSH and GB2626 respectively) on the mask surface. |
| Facial Coverage | Both N95 and KN95 cover the nose, mouth, and chin with a tight-fitting seal. |
| Particle Capture Range | N95 and KN95 both effectively capture bacteria, viruses, dust, and other particulate matter. |
| Quality Control Testing | Both N95 and KN95 undergo rigorous quality control testing on every production batch. |
| Cost Range | N95 and KN95 masks both typically cost between $1 and $5 per unit when purchased in bulk. |
The deciding variable is your exposure setting. Choose N95 for high-risk, prolonged contact in healthcare or crowded indoor spaces. Choose KN95 for everyday public use with lower viral load. Both filter 95% of 0.3-micron particles, but N95 offers superior fit and seal integrity.
Choose N95 when you need maximum respiratory protection in high-exposure environments. This includes hospital wards, COVID-19 patient care, or crowded buses during surges. N95s undergo NIOSH testing with stricter quality standards. Use them for 8-hour shifts where fit is critical. They cost $1–$3 per mask, making them ideal for essential workers.
Choose KN95 when you need reliable filtration for standard public activities with lower transmission risk. This covers grocery shopping, office commutes, or school drop-offs. KN95s feature ear loops, enabling faster donning and removal. They meet Chinese GB2626-2006 standards, not NIOSH. Use them for 4–6 hour errands. At $0.50–$1.50 each, they suit budget-conscious daily wear.
| Common Myth | The Reality |
|---|---|
| "N95 and KN95 are exactly the same mask." | N95 follows US NIOSH standards, while KN95 follows Chinese GB2626 standards; both filter 95% of particles but test differently. |
| "KN95 masks provide less protection than N95 masks." | Both N95 and KN95 filter at least 95% of airborne particles; real-world protection depends on fit, not the certification label. |
| "N95 masks are always tighter fitting than KN95." | Fit varies by brand and face shape; a KN95 with ear loops can seal better on some faces than an N95 with head straps. |
| "KN95 masks are not regulated or tested." | KN95 masks are regulated by China's GB2626 standard, which includes filtration efficiency, breathing resistance, and leakage tests. |
| "N95 masks are only for healthcare workers." | N95 respirators are available to the public; the CDC recommends them for general use during high-risk exposures, not just medical settings. |
| "KN95 masks cannot block viruses because they lack FDA approval." | Many KN95s received FDA EUA during the pandemic; FDA approval is not required for general public use, only for medical claims. |
| "All N95 masks are fluid-resistant." | Only surgical N95s are fluid-resistant; standard N95s lack that property, so they are not suited for splash protection in surgery. |
| "KN95 ear loops always cause more leakage than N95 head straps." | Ear loops often fit looser, but adjustable ear loops or mask brackets can create a seal comparable to N95 head straps. |
| "N95 masks filter more particles than KN95 masks." | Both N95 and KN95 must capture at least 95% of 0.3-micron particles; neither filters more than the other by design. |
| "KN95 masks are counterfeit if they have ear loops." | Ear loops are standard on genuine KN95s; counterfeit detection relies on missing GB2626 markings or false NIOSH claims, not loop type. |
| "N95 masks are reusable if you let them air out." | Air drying reduces moisture but does not remove viral contamination; reuse is limited to 5 donnings per CDC crisis guidance, not indefinite. |
| "KN95 masks are not effective against Omicron variants." | Both N95 and KN95 block aerosol particles carrying any variant; filtration efficiency remains above 95% regardless of mutation. |
| "N95 masks are too expensive for everyday use." | Bulk N95 prices dropped below $1 per mask in 2024; disposable KN95s cost $0.50–$0.80 each, making both affordable for daily wear. |
| "KN95 masks are not suitable for children." | KN95s come in pediatric sizes; the issue is fit, not the standard, so a properly fitted child KN95 offers equivalent protection to an N95. |
| "N95 masks cause carbon dioxide buildup that harms you." | N95 and KN95 respirators allow CO2 to escape through exhalation valves or filter material; CO2 levels stay below OSHA limits during normal breathing. |
| "KN95 masks are less breathable than N95 masks." | Breathing resistance depends on the filter layer and pressure drop; many KN95s have lower pressure drop than N95s, making them easier to breathe through. |
| "N95 masks are only for single-use and cannot be sanitized." | UV-C light or dry heat at 70°C for 30 minutes can decontaminate N95s without degrading filtration, per CDC emergency protocols. |
| "KN95 masks do not protect against dust or pollution." | KN95 filters at least 95% of non-oil particles, including PM2.5 dust and smoke; they are widely used in Chinese cities for air pollution. |
| "N95 masks are all the same size and shape." | N95s come in flat-fold, cup, and duckbill styles; sizes vary from small to large, so fit testing is essential for a proper seal. |
| "KN95 masks are not accepted in US hospitals." | During the pandemic, the FDA authorized imported KN95s for healthcare use when N95 supplies ran short; they are accepted under EUA. |
| "N95 masks are safer because they are tested on humans." | Both N95 and KN95 use manikin-based fit tests; human fit testing is a separate OSHA requirement that applies to both types in workplaces. |
| "KN95 masks have no exhalation valve options." | Valved KN95s exist; they improve comfort but do not filter exhaled air, so they are not recommended for source control in public settings. |
| "N95 masks are always white or blue." | N95s come in multiple colors and styles; color is not a quality indicator, and some brands sell black or pink N95s for consumer preference. |
| "KN95 masks are only for Asian face shapes." | KN95 dimensions are based on Chinese anthropometric data, but many Western brands now offer larger KN95s; fit testing is the only reliable check. |
| "N95 masks are not effective if you have a beard." | Facial hair breaks the seal on both N95 and KN95; clean-shaven skin is required for a tight fit, regardless of the mask standard. |
| "KN95 masks are not NIOSH-approved, so they are inferior." | NIOSH approval is a US-specific certification; KN95's GB2626 standard is equivalent in filtration, but it is not NIOSH-approved by design. |
| "N95 masks protect against chemical vapors and gases." | N95 and KN95 only filter particles; they do not adsorb gases or vapors, so they are useless against chemical fumes like chlorine or ammonia. |
| "KN95 masks are too thin to offer real protection." | KN95s use multiple non-woven layers plus a melt-blown filter; thickness is not a measure of efficiency, as the melt-blown layer does the work. |
| "N95 masks are the only respirators that meet WHO standards." | The WHO accepts N95, KN95, FFP2, and KF94 as equivalent respirators; all filter ≥94% of particles, so no single standard is exclusive. |
| "KN95 masks are always counterfeit if sold online." | Legitimate KN95s are sold by authorized distributors with GB2626 documentation; counterfeits exist but are detectable via missing markings or fake NIOSH logos. |
Difference Between N95 and Kn95 comes down to certification: N95 meets U.S. NIOSH standards, while KN95 follows Chinese GB2626 requirements. Both filter at least 95% of airborne particles. Choose N95 for U.S. healthcare settings; choose KN95 when N95s are unavailable or for general public use.
## FAQ ### What is the difference between N95 and KN95 respirators? The primary difference between N95 and KN95 respirators lies in their certification standards: N95 is the U.S. NIOSH standard requiring a minimum 95% filtration of airborne particles, while KN95 is the Chinese GB2626-2006 standard with the same 95% filtration efficiency but tested under different protocols. ### Which is better for protection, N95 or KN95? N95 respirators are generally considered better for U.S. healthcare settings because they are regulated by NIOSH with stricter quality assurance, including requirements for headbands and rigorous fit testing, whereas KN95 respirators often use ear loops that can compromise the seal and are not automatically approved for medical use. ### How much does an N95 respirator cost compared to a KN95? An N95 respirator typically costs between $1.50 and $5.00 per unit when purchased in bulk, while a KN95 respirator usually ranges from $0.50 to $2.00 per unit, making KN95 masks roughly 50-70% cheaper due to lower manufacturing and certification costs in China. ### Are KN95 respirators safe to use for everyday public activities? Yes, KN95 respirators are safe for everyday public activities like commuting or shopping, provided they come from a legitimate manufacturer with documented filtration test results, because they still block at least 95% of particles and offer comparable protection to N95 when worn correctly. ### Can I use a KN95 mask in place of an N95 at a U.S. hospital? No, you cannot use a KN95 mask in place of an N95 at a U.S. hospital unless it has been specifically authorized under an FDA Emergency Use Authorization, because NIOSH-approved N95s are the required standard for healthcare workers to ensure a verified fit and filtration performance. ### What is the most common mistake people make when choosing between N95 and KN95? The most common mistake people make when choosing between N95 and KN95 is assuming all KN95s are counterfeit or inferior, but in reality, many KN95s perform equally well; the real error is failing to check for NIOSH approval or proper fit, which matters more than the label. ### Are N95 and KN95 respirators interchangeable for protection against COVID-19? Yes, N95 and KN95 respirators are largely interchangeable for protection against COVID-19 in non-surgical settings, because both filter at least 95% of aerosol particles, but the N95's headband design typically provides a more reliable facial seal than the KN95's ear loops. ### Which respirator should I buy for construction work with dust and particles? For construction work with dust and particles, you should buy an N95 respirator because it is certified by NIOSH for occupational use in the U.S., ensuring consistent quality and a secure fit, whereas KN95s are not legally approved for workplace protection under OSHA regulations. ### Can I switch from wearing an N95 to a KN95 without losing protection? Yes, you can switch from wearing an N95 to a KN95 without losing significant protection if you pass a fit test and the KN95 has verified filtration data, but be aware that ear-loop designs often leak more, so a tight seal is critical for equivalent performance. ### How do I verify if a KN95 mask is genuine and not counterfeit? To verify if a KN95 mask is genuine, check for the GB2626-2006 standard marking, a manufacturer name, and a lot number on the packaging, then cross-reference the brand with the FDA's authorized list or request test reports showing ≥95% filtration efficiency at 0.3 micron particle size.