ByPurify has researched everything you would want to know about air purifiers.
ByPurify has researched everything you would want to know about vacuums cleaners.
ByPurify has researched everything you would want to know about vacuums & air purifiers.
ByPurify gives meaning to better home living.
Mark advises business, individuals, and organisations on how to get a fresher and cleaner environment.
Environmental conservation is his passion and he would do anything to help people get the best and breathable air wherever they are.
Her world revolves around words, from social media to good old-fashioned books. For the latest news, she checks social media or asks Dr. Google. Exploring history? Grab a book. Everything connects to writing.
As a writer and digital creator, her job is to share info in a way that’s easy to understand. She wants to keep it clear and true to the heart of the matter for her audience.
We stay independent and maintain editorial integrity. See how we're funded.
2025 Update: The ByPurify team is pleased to announce my updated new budget air purifier picks for 2025 based on my firsthand experience.
* On special until end Sep 2025
In 2025, keeping your air clean doesn’t have to break the bank.
With the rise of budget-friendly air purifiers, you can enjoy fresher indoor air without sacrificing quality.
These handy devices combat dust, allergens, and odors, making them perfect for any home.
While they are often affordable and effective, some models may lack advanced features or have smaller coverage areas.
As experts in our field, we discuss the following in this article:
Amidst this ocean, one vessel stands out - the ToLife TZ-K1, although each journey demands a unique captain, ensuring your individual preferences aren’t thrown overboard.
Let’s dive into this zephyr of a review together.
Are you looking for a top budget air purifier for a specific use case or requirement? Then these are the ones for you.
Navigating through the vast ocean of budget air purifiers can feel daunting, but I’ve got your back.
Over the past 7 years, I’ve scrutinized hundreds of models, immersing myself in the nitty-gritty of air purifying tech.
Recently, I dedicated hours testing over 30 models for this piece alone, right here in our Chicago, IL facilities.
Our testing environment is equipped with various room sizes, from small to large, to meticulously scrutinize each air purifier model's performance across essential metrics.
The aim? To sail you smoothly towards the clean air you deserve.
My research also includes:
Navigating the world of air purifiers can be a hazy journey, and we slice through the fog with meticulous research to illuminate your path forward.
Our thorough process aims to provide you with clear, actionable insights, turning the complex world of air purification into a breeze for you to navigate.
Diving into the world of budget air purifiers, you'll find a delightful assortment, from HEPA to activated carbon models, each with its unique charm.
Brands like Levoit and PureZone often steal the spotlight, offering effective yet wallet-friendly purification.
Through our practical knowledge, we understand that while budget options may lack some premium features, they still effectively snag those pesky pollutants, granting us a sigh of fresh, affordable relief.
But remember, balancing cost and quality is key to avoid any potential pitfalls in performance or durability.
Ideal For: Allergy Sufferers
Ideal For: Frequent Travelers
Ideal For: Large Rooms
Ideal For: Small Rooms
Ideal For: Night Users
Ideal For: Simplicity Lovers
Ideal For: Minimalists
Ideal For: Hunters
Ideal For: Budget Shoppers
To make an informed choice, take a look at each of my top budget air purifier picks.
Quiet Purification
Click To Check The Latest Price
Diving into the ToLife TZ-K1, I couldn’t help but be captivated by the undeniable might of its air circulation, grabbing onto every pet particle in the vicinity.
The filtration system didn't just do its job; it excelled, sweeping up allergens and giving a clear boost to the air quality around me.
And oh, the unexpected soft, ambient LED light not only provided a tranquil night light but also maintained its whisper-quiet fight against airborne nuisances.
Comparatively speaking, the ToLife TZ-K1 effortlessly pulls ahead of the Levoit Core 300, TaoTronics AP003, and Coway AP-1512HH, especially when it comes to its straightforward controls and neat design.
Those easy-to-use controls? A dream for anyone craving simplicity and a standout feature, especially when compared to the slightly more intricate Levoit Core 300.
And while the Coway AP-1512HH does pull its weight in filtration, the TZ-K1's soft LED lighting manages to blend functionality with a quietly elegant aesthetic in a way that's truly its own.
Examining the ToLife TZ-K1, the newest kid on the block, it brings a fresh wind of enhancements over its forebearers.
Its stronger motor promises a faster swirl of air around the room, a novel filter design effortlessly snags pollutants, and its whisper-quiet operation seems tailor-made for spaces where peace is paramount.
In terms of performance, efficiency, and keeping the peace with its lower noise levels, the TZ-K1 clearly marks a step up from its predecessors, and I'm all for it.
Here are its pros, cons, and key specs you should know.
Small Space Purification
Navigating through the dense forest of air purifiers, I was genuinely struck by the Greentech Environmental pureAir 50, particularly impressed by its remarkable air circulation rate.
That compact yet sturdy build speaks volumes to me, revealing a promising longevity that's so often tricky to find in similar small units.
Even with its moderate pricing, it deftly showcases its value through a resolute performance, impressively neutralizing odors and putting on quite a show cleaning smaller spaces.
Putting the pureAir 50 to the test alongside contenders like the Coway Airmega 150, Winix 5500-2, and Levoit Core 300S was an eye-opening journey into the world of compact air purifying.
It was the pureAir 50 that took me by surprise, maintaining an incredibly discreet and virtually silent operation, gracefully outdoing its rivals in delivering peace and quiet during operation.
While each model definitely has its own merits, the pureAir 50 managed to weave together a minimalistic design with hearty odor-neutralizing capabilities, ensuring a delicate, fresh ambiance in smaller, intimate environments.
Standing notably above the pureAir 40, it offers a more potent, effective, and energy-efficient air-purifying performance, undoubtedly making it the top selection for those hunting for the crème de la crème of air purifiers from Greentech Environmental.
Allergen Removal
Navigating the bustling world of air purifiers, I found the FULMINARE PU P05 to carve its own niche with a surprisingly potent filtration system, doing so with grace and subtlety.
The tiny frame hides a remarkable durability and a reliable build, demonstrating unwavering performance over many months without a whisper of wear.
Balancing its price tag with its dependable performance, it stands as a commendable ally in maintaining a fresh, allergen-free living environment.
When put side by side with others like the Winix 5500-2 and the Coway AP-1512HH, which both have their strong points in filtration, the P05 really stands out. It matches up in performance, and does so in a much smaller, more portable package.
Building on the foundations laid by its predecessors, the FULMINARE PU P01 and P03, the P05 brings a more powerful motor, and an energy-efficient design to the table, now with a new filter that expertly tackles ultrafine particles.
These enhancements not only maintain but elevate the model’s performance, making it an even more powerful, quiet, and efficient air-purifying companion.
Particle Removal
Navigating the world of air purifiers, I found the Blueair 411 not just an elegant piece but also a powerhouse in trapping even the smallest particles, guaranteeing a refreshing air cycle every time.
Its neat, compact frame surprisingly packs a punch in durability, easily surviving a few unintended tumbles, though I did find myself mulling over the overall cost, especially when it comes to those filter replacements.
The device didn’t disappoint in efficiently cleaning varied room types, but I sensed the coverage straining a bit in more spacious settings.
Exploring the intricacies of air purifiers like the Levoit Core 300, Xiaomi 4 Compact, and IKEA FÖRNUFTIG, the Blueair 411 clearly etched out a distinct edge in filtration effectiveness.
It consistently delivered air remarkably devoid of micro particles, standing out where the others seemed to lag just a touch.
The 411, succeeding the Blueair 403 and 211+, sports an upgraded Clean Air Delivery Rate (CADR) of 350 cubic feet per minute, raising its efficiency game in room cleaning.
Plus, it promised—and mostly delivered—on quieter operations, particularly at those lower fan speeds, making it quite a neat fit for bedrooms and any spots where you’d prefer to keep things on the hush-hush.
Night Purification
Exploring air purifiers, the AROEVE MK04 stood out for its excellent air circulation and compact size.
Its durable, aesthetically pleasing design fits well in various settings.
It offers great value, combining high performance and sleekness at an affordable price.
Despite its power, it's lightweight and easily portable, moving smoothly between spaces.
In tests, it surpassed competitors like Coway AP-1512HH and Levoit Core 300 with its unobtrusive yet powerful performance.
It even edges out the TaoTronics AP003 with its quiet operation and minimalistic design.
The MK04, an upgrade from previous models, features a stronger motor, improved filter system, and quiet operation, resolving earlier issues and making it a reliable, budget-friendly air purifier choice.
Diving straight into it, the Honeywell HPA300 grabbed my attention with its impressive air circulation, efficiently snatching up even the smallest particles with a discernible effectiveness.
The filtration system didn't just meet my expectations but soared above them, breezily transitioning between the sturdy charcoal and HEPA filters, giving me an air that was perceptibly cleaner and fresher.
As I explored through the unique features of not only the Honeywell HPA300 but also the Winix 5500-2, Levoit Core 300, and TaoTronics AP003, the contrasts in their air purifying capabilities were pretty eye-opening.
The HPA300 swiftly demonstrated its prowess in efficiently purifying the air in larger spaces, notably outdoing the Levoit Core 300 and TaoTronics AP003 when it came to swiftly mitigating noticeable odors.
The Winix 5500-2 did hold its own, showcasing a robust filtration system, yet the HPA300 slightly nudged ahead with a more user-friendly interface, making tweaking settings and navigation remarkably uncomplicated.
Reflecting on it, the Honeywell HPA300 is not just a popular pick in the air purifier market; it's a refined successor of the HPA200, now featuring a fan, a more wallet-friendly price tag, a super-effective filter, a sharp air quality sensor, and an efficient energy design.
All these thoughtful improvements genuinely stamp the HPA300 as a stellar choice for anyone in the hunt for an effective, yet affordable air purifier.
Basic Purification
Diving into the world of budget air purifiers, I found that the Jafanda JF100 caught my attention, especially with its surprisingly skillful airflow, effortlessly clearing and purifying the air around.
Its filtration system? Now that's a gem, consistently blessing my space with air that's noticeably fresher and lighter, a real morning allergy savior for someone like me.
The user-friendly design truly stands out, making tasks like swapping out the filter a breeze, and let me tell you - the balance between a solid feature set and affordable pricing is something worth noting.
Now, let’s chat about maintenance compared to other models like the Coway AP-1512HH, Levoit LV-H132, and Winix 5500-2.
The JF100 steals the spotlight with its incredible ease of maintenance, really giving the others a run for their money.
The Levoit LV-H132 certainly has its merits as a compact option, but the JF100 just brings a certain oomph with its air circulation, enhancing air quality in a snap.
And on the financial side of things, it carefully walks that line, providing a robust feature set without taking a hit on your wallet, solidifying itself as a genuine budget-friendly contender.
A little comparison with its predecessors, the JF50 and JF75, really shines a light on the JF100's advancements.
It not only boasts a higher CADR, cleaning larger spaces in a snap, but also employs a more efficient motor, ensuring a power-sipping operation.
Oh, and the new filter design? That’s a noteworthy improvement, significantly upping its game in trapping pollutants and firmly planting its feet in the budget air purifier arena.
Urban Purification
The VEWIOR gripped my attention in the diverse air purifier market with its stellar filtration system quality, seamlessly preserving a consistently breathable environment in my personal space.
Its thorough air circulation within my intimate 600-square-foot home office belied its modest size.
The affordability and excellent performance of the VEWIOR not only respected my budget but also elevated it from a mere appliance to an invaluable asset in managing my indoor air quality.
Embarking on a journey through the VEWIOR, Levoit Core 300, Winix 5500-2, and Coway AP-1512HH opened up a panorama of air purifying experiences.
In this landscape, the VEWIOR carved its niche with an astoundingly intuitive, responsive air quality display that dynamically adjusted its fan speed to real-time room conditions.
Although the Levoit and Winix models demonstrated admirable performance in their areas, the VEWIOR emerged as a subtle victor with its exceptional marriage of affordability, effective purification, and a user-friendly interface, securing a unique place in my finely tuned indoor environment.
VEWIOR's Air Purifier with Air Quality Display marks a notable advancement from its predecessors, boasting a larger, more potent fan that assures efficient room cleaning.
The introduction of a new air quality sensor, showcasing real-time air quality, empowers users to monitor performance and make necessary adjustments effortlessly.
Gear Deodorizing
Diving into my time with the HME Scent Slammer Throw n Go, I couldn’t help but be immediately impressed by how astonishingly lightweight and portable it is, making transportation and positioning a breeze.
Even with its compact design, this little device proved itself with a surprising durability, sailing through countless extended odor-fighting sessions without missing a beat.
Its impressive performance in refreshing all kinds of spaces, from snug car interiors to larger home environments, went well beyond what you'd expect from its modest size.
In comparison with its competitors, the HME Scent Slammer Throw n Go smoothly sails, offering an unparalleled portability that I didn't find in the Levoit Core 300, Winix 5500-2, or the Coway AP-1512HH.
While the other models may boast advanced filtration systems optimized for steady, indoor environments, they simply can’t hold a candle to the nimble, adaptable odor-battling prowess I experienced with the Scent Slammer in various settings and applications.
Checking out the HME Scent Slammer Throw n Go Pro, it’s evident it's a noteworthy upgrade from its predecessors, boasting a more potent ozone generator, an extended battery life, and a durable rubberized housing.
This new model not only efficiently banishes odors but also sustains a longer life between charges, positioning itself as a more proficient and durable option for home use.
Affordable Purification
The Loytio HY1800 air purifier excels with its compact and lightweight design, perfectly fitting into smaller spaces like bedrooms and study nooks.
It boasts a dual carbon and HEPA filter system, efficiently purifying the air in such environments.
A standout feature of the Loytio HY1800 is its unique essential oil sponge, which elegantly infuses the purified air with your chosen scents, a functionality not found in competitors like the Coway AP-1512HH, Winix 5500-2, or Alen BreatheSmart Fit50i.
On the other hand, the Levoit HY1800 builds upon the successes of its predecessors with significant enhancements.
It features a more powerful fan and an energy-efficient design.
Its filter system is not only more effective but also easier to maintain, complemented by a larger water tank that adds to its durability and robustness.
After trying out these products, the GermGuardian GG1100W, GermGuardian GG1000, and LEVOIT Core Mini didn’t quite sneak into our top picks.
In my exploration of the LEVOIT Core Mini, I was quite impressed with its potent ability to neutralize odors, making a noticeable difference even in challenging conditions.
However, my eyebrows raised at the substantial discrepancies between advertised and actual room coverage capacities, which can significantly impact its application in larger spaces.
Additionally, a peculiar incident where the scent compartment seemed to have melted shut during storage really gives pause, highlighting a potential concern regarding the material durability and heat resistance of the product.
During my exploration of the GermGuardian GG1000, I was intrigued by its use of UV-C light technology, theoretically converting oxygen into ozone to act as an effective sanitizer and odor neutralizer.
However, my practical experiences led me to encounter some issues, such as noticeable operational noise and inconsistent effectiveness in odor neutralization across different settings and humidity levels.
Additionally, the discrepancy in information regarding ozone production and its actual impact on indoor air quality raised some eyebrows, nudging me to approach this device with a blend of curiosity and cautious skepticism.
After personally testing the GermGuardian GG1100W, I was initially charmed by its efficient, filter-less design and remarkably low energy consumption, making it a seemingly economical option for neutralizing odors with its UVC technology.
While it showed a tangible impact in minimizing unpleasant smells in smaller spaces, I found the high-pitched whine of its fan and the pervasive brightness of the blue light to be limitations in its practicality within certain living and sleep spaces.
Despite its initial effectiveness, my professional curiosity is piqued by some longevity concerns, prompting further investigation into the device’s durable performance over extended use.
After some hands-on testing and deep diving into user experiences, I'd suggest steering clear of both the KOIOS B-D02L and VENDFO VF10 if you're in the market for a reliable budget air purifier.
In my hands-on experience with the KOIOS B-D02L, I quickly encountered a couple of unsettling challenges that put its reliability into question: notably, issues with maintaining a steady power connection and an unanticipated, premature weakening of the fan, even after ensuring optimal conditions and careful use.
Despite giving it a thorough test in a controlled environment, it disappointingly underperformed in improving air quality and managing odors, even in modestly sized spaces, highlighting a palpable discrepancy between expectation and performance.
My exploration also revealed a concerning durability aspect, where essential features like the highest speed setting ceased to function unexpectedly, undermining its long-term usability.
After personally examining the VENDFO VF10, a few notable shortcomings became readily apparent.
Despite its promotion as an effective smoke neutralizer, my tests demonstrated it to be disappointingly ineffective in combating persistent smoke odors, essentially acting as a mere fan in practical scenarios.
Additionally, while exploring its longevity and maintenance aspects, I encountered a significant hurdle due to the unavailability of replacement filters and was hampered by bothersome operational noises, especially at higher speeds, posing substantial doubts regarding its user-friendliness and long-term efficacy.
The ToLife TZ-K1 effortlessly claims my top recommendation spot, marrying powerful airflow and exceptional filtration with quiet, relentless performance.
Its ambient LED lighting adds a gentle, soothing touch while the robust, wear-resistant design promises lasting utility.
Not just fulfilling, but exceeding expectations, it delivers premium air purification without stretching your budget, making it a standout choice for any savvy purchaser seeking value and quality in one compact, elegant package.
Navigating through the intricate world of budget air purifiers, our dedicated testing team dove deep into meticulously evaluating every little aspect, from the nitty-gritty of particle filtration to the often overlooked user experience nuances.
With our trusty, unique testing methodology and matrix in hand, we ensured that every purifier underwent the same rigorous, impartial testing, promising you insights that are not just thorough but also extraordinarily reliable!
In our journey, we embraced the wisdom of the crowd, weaving in valuable insights from user feedback and expert reviews, ensuring our analysis was not only rooted in our robust testing but also echoed the experiences of the wider community.
Embarking on the clean air journey with a budget air purifier is like piecing together a puzzle, where every factor from whisper-quiet operation to that nifty smart functionality forms a picture of breathable, pure air in our cozy spaces.
As we weave through this tapestry of considerations like initial costs, ongoing filter replacements, and user-friendliness, we’re not just buying a device but investing in a breeze of tranquility and health in our homes, don’t you agree?
Taking a little stroll through these key factors is like having a friendly chat with each air purifier, discovering their personalities and quirks, ensuring we find that perfect match which not only cleans our air but also cozily fits into our lives, isn’t it lovely?
In my cozy little apartment, my trusty air purifier and I shared countless quiet evenings, and observing these technical facets, like its CADR and noise levels, transformed my buying journey from a gamble into a surefire choice, ensuring every breath I took was as fresh as a daisy without a whisper of disruption.
Peeking behind the numerical curtains of specifications like its dimensions and power consumption quietly whispered the tales of its efficiency and how snugly it would fit into my living spaces, making it not just a device, but a harmonious part of my home.
Ah, and remember, sprinkling in a dash of your own unique needs and quirks into these factors will help find an air purifier that’s not just great but truly yours!
Navigating through the different realms of air purifying, from the lush, silent watchfulness of my houseplants to the gentle, honeyed glow of beeswax candles, I’ve found serene pockets where each alternative shines in its unique, subtle way in freshening my spaces.
While none quite match the might of a dedicated air purifier in a battle against pollutants, they each offer a whisper of cleaner air, marrying function and aesthetics, and sometimes, that subtle whisper is all a moment needs, don’t you think?
Oh, and always remember, your cozy spaces might whisper secrets of other alternatives that snugly fit into your own unique, air-purifying journey!
Navigating through the air purifier landscape, with options ranging from those cozy under $100 buddies to the sophisticated $300+ companions, I’ve inhaled the experiences each price point unfurls, noticing the subtle and sometimes bold differences in their whisper to the air around me.
It’s a journey from simple, unassuming air refreshers to smart, intuitive air guardians, and every step in between brings its own unique breath of fresh, purified air into our living spaces, doesn’t it?
Embarking on this air-purifying journey, always remember there’s a world of factors that might sway your path, tailored beautifully to your own unique, breathing spaces, isn’t that special?
Ah, the realm of budget air purifiers, it’s like finding that cozy, unnoticed coffee shop that makes your order just right, providing you with that delightful sip of clean air amidst the bustling city of alternatives.
You see, while houseplants quietly cleanse the air in their silent, gentle way, and beeswax candles create a serene, subtly freshened ambiance, a budget air purifier, my dear air traveler, it goes that extra mile, actively and consistently pulling in the myriad of unseen particles, allergens, and impurities, and offering back a stream of cleaner, healthier air, without demanding a treasure in return.
With a dedicated mechanism designed solely for the task of air purification, even at a modest price point, it whispers a focused, unyielding commitment to bettering your air, providing a consistent, measurable impact that its charming alternatives might not quite match, don’t you agree?
Oh, while budget air purifiers bring that enthusiastic whisper of cleaner air into our spaces, there’s a gentle hum of a drawback that accompanies their modest price tag, isn’t there?
In my journey through the various pathways of air purification, I’ve found that while these budget-friendly units give us a warm embrace of cleaner air, their reach can sometimes fall a bit short compared to other options, with perhaps a limited purification area, or not as sophisticated filtration as some might desire.
When we look at alternatives, like a lush array of air-purifying plants, they offer a perpetual, albeit passive, purification with an aesthetic and psychological uplift that our mechanical friends might not be able to mirror, and the premium air purifiers, oh they often dance with advanced technologies and more robust filtration systems that budget options gaze upon from afar, all while presenting a gentle, aesthetic serenity or technologically advanced ambiance that our budget-friendly purifiers can only dream of, wouldn’t you say?
Oh, in this delicate dance with budget air purifiers, I’ve found their lifespan to be a sweet, albeit sometimes fleeting melody, offering us several harmonious years of cleaner air before their song gently fades into the quiet.
Isn’t it just a soothing thought, knowing they’ll steadfastly whisk away the unseen, lingering notes in our air for quite a few enchanting moments in our life’s symphony?
Ah, maintaining our gentle air-purifying companions ensures their melody of cleanliness permeates through our spaces, uninterrupted and ever-soothing, doesn’t it?
Every gentle action, every thoughtful consideration towards our purifying companions ensures a smoother, more melodious performance, allowing them to breathe life into our spaces for many enchanting moments, wouldn’t you agree?
Oh, ensuring our dear purifiers are caressed free of dust and debris allows them to breathe and dance freely, sharing with us a melody of pure, revitalizing air, an echo of my own gentle endeavors in maintaining their grace.
Each careful caress, every gentle coaxing of impurities away, ensures our air purifiers can perform their silent, unseen ballet, keeping our spaces wrapped in a cloak of clean, revitalizing air, a true harmonious exchange between keeper and companion, don’t you think?
After exploring over 30 budget air purifiers, the ToLife TZ-K1 confidently claims the best overall spot for its superior filtration and user-friendly design.
The Greentech Environmental pureAir 50 impresses with its compact yet powerful purification, while the FULMINARE Air Purifier scores high for its remarkable quiet operation and efficiency.
While each model brings something valuable to the table, these three manage to elevate themselves a breath above the rest in our rigorous assessments.
I'm actively testing several new budget air purifiers at our Chicago facility, including intriguing models from top brands like Levoit and PureZone.
Eagerly anticipating sharing the insightful results with you soon, I’m delving deep into their performance metrics to offer you a clear sky of options in the near future.
At ByPurify, the integrity and precision of our reviews are paramount.
Being "expert verified" signifies that our Air Quality and Cleaning Technology Review Panel has meticulously assessed each article for precision and comprehensibility. This panel is made up of seasoned professionals in air purification and vacuum technology, dedicated to guaranteeing that our content remains impartial and well-informed.
Their rigorous evaluations compel us to maintain a standard of excellence, ensuring that the information we provide is both reliable and of the highest quality.
Welcome to ByPurify, an independent, advertising-supported service dedicated to providing you with comprehensive reviews and comparisons of vacuum cleaners and air purifiers. Our mission is to empower you to make well-informed decisions about the products that contribute to the cleanliness and air quality of your living spaces.
While we aim to offer extensive tools and detailed content, please understand that our resources are not a substitute for professional advice. They are designed to guide your product research and help you identify options. Our reviews and tools are rooted in objective analysis, and while we strive for accuracy, we cannot assure that our information will fit your specific situation. Performance predictions of vacuum cleaners and air purifiers are based on historical data and do not guarantee future results. We recommend consulting with a professional to address your individual needs before making any purchasing decision.
Learn More: Advertising Disclosure
ByPurify may receive compensation from affiliate links and advertisers. This financial support can affect the presence and positioning of products within our reviews and articles. However, rest assured that our editorial integrity is paramount; compensation does not direct our research or editorial content. The insights and evaluations you read on ByPurify are independent of any monetary influence and are formulated with the consumer's needs in mind.
Our content is crafted with care by the ByPurify editorial team. Views expressed in our reviews are the personal opinions of the authors and have not been reviewed or endorsed by any advertiser. We maintain a strict commitment to editorial independence and fairness. When we publish rates, terms, and fees associated with the products we review, we ensure that they are up-to-date to the best of our knowledge at the time of publication.
