People tend to judge air quality by smell or visible dust. “But many of the most consequential indoor pollutants — PM2.5, PM10, ultrafine particles, VOCs, and nitrogen dioxide — are invisible and odourless. A space can look entirely clean and still carry pollutant levels that quietly affect respiratory health over time,” Dyson engineer Alex Hudson tells this newspaper over email.
He says what matters most is consistency over time rather than a single favourable reading. “According to Dyson Global Connected Air Quality Data research, India recorded the highest average annual indoor PM2.5 levels of all 39 countries studied, exceeding the WHO annual guideline by 11 times. Delhi homes exceeded that guideline by 14 times. And here’s what surprises most people: unlike many other countries where indoor pollution peaks late at night, in India the most polluted period inside the home is between 7am and midday, right when families are waking up, cooking breakfast, and beginning their day.”
Hudson joined Dyson in 2018 through the Dyson Institute of Engineering and Technology (DIET), where he graduated in 2022. His work focuses on developing new concepts tailored to the unique needs of consumers in India and Japan. Can Dyson vacuum cleaners and air purifiers come to your rescue? Here’s what Hudson has to say.
Indoor environments can be a closed loop for allergens. Can you walk us through what that loop looks like in a typical Indian home, and why it’s so hard to break?
Think of allergen circulation in a home as a loop that never naturally resolves on its own. Fine particles like pollen, dust mite debris, and pet dander settle onto floors, bedding, and soft furnishings. The moment someone walks across the room, sits down, or pulls back the sheets in the morning, those particles become airborne again. They are extraordinarily small — often far smaller than the width of a human hair — which means they can remain suspended in the air for extended periods before settling once more, only to be disturbed again.
Dyson’s Global Connected Indoor Air Quality Data Research shows that indoor PM2.5 levels can remain elevated for extended periods, frequently exceeding safe limits across months, which tells you just how persistent this cycle is.
What makes this loop particularly difficult to break in Indian homes is that it operates at two distinct levels simultaneously.
At the surface level, settled dust continuously re-enters the breathing zone through everyday movement and keeps being disturbed back into the air. At the same time, cooking, cleaning, and other daily activities introduce gases and odours that linger in enclosed spaces, adding a gaseous dimension that requires filtration to address. Purifying the air and removing surface dust is therefore the way to break the loop.
Most people sweep, mop, or wipe surfaces and consider their home clean. Where exactly does that approach fail, scientifically?
Traditional cleaning methods — sweeping, mopping, and wiping — mainly move dust and dirt instead of truly removing them. When you sweep, fine particles often become airborne or settle elsewhere, never completely contained. Mopping can be even more problematic. Dyson’s 2025 Global Wet Cleaning Study found that 49 per cent of people in India do not change mop water between rooms. So instead of eliminating dirt and microbes, they are spreading them.
From a scientific standpoint, effective cleaning is defined by one thing: capturing particles at source and preventing them from re-entering the environment. That requires a sealed system — one that traps what it picks up rather than recirculating it through exhaust or gaps.
The Dyson V12s Detect Slim Submarine is designed with a fully sealed filtration system that traps dust and allergens inside, stopping them from leaking out. For wet cleaning, its unique Submarine wet roller constantly extracts dirty water into a separate tank, ensuring only clean water contacts your floors when tackling wet spills. Laser dust detection brings invisible particles to light, so users can see and remove what ordinary cleaning leaves behind. By combining sealed filtration with consistent extraction and particle visibility, the V12s does not just shift dirt — it removes it completely, setting a new standard for home hygiene.
From an engineering standpoint, what are the hardest problems to solve when designing a product meant to capture both settled and airborne particles?
The fundamental challenge is that settled and airborne particles are two entirely different physical problems. Larger debris settles predictably and is relatively straightforward to capture. Fine particles like PM2.5 are far more complex — generated by everyday activities like cooking or cleaning, they remain suspended for extended periods and move unpredictably within a space.
For airborne particles, three requirements must work in concert: detecting pollution in real time, capturing ultrafine particles without restricting airflow, and ensuring those particles stay trapped once caught. A fully sealed system is non-negotiable; even minor leakage allows particles to bypass filtration entirely. And filtration alone is not sufficient — the machine must project clean air effectively across the room.
In the Dyson HushJet Purifier Compact, that is precisely the balance we have engineered: intelligent sensing, a charged 360-degree electrostatic filter with an activated carbon layer, all within a sealed system that projects purified air throughout the space rather than just cleaning the air immediately around it.
At the surface level, the act of cleaning can itself generate airborne pollution if the system is not sealed — disturbing fine dust and releasing it back into the breathing zone defeats the purpose. There is also a visibility problem that is easy to underestimate: much of the fine particulate matter on hard floors is simply invisible to the naked eye, so you are essentially asking someone to clean what they cannot see. That is something we have worked to solve in the Dyson V12s Detect Slim Submarine, where green laser illumination reveals otherwise invisible dust and a sealed system ensures what is captured stays captured.
Holding all of this — filtration quality, airflow projection, real-time sensing, and sealed surface-level capture — in balance without sacrificing one for another is where the genuine engineering complexity of this problem lies.
How does Dyson’s approach to filtration differ from conventional air purifiers, particularly for sub-micron particles that carry allergens?
Dyson purifiers use fully sealed machines, and this ensures the machine captures 99.95 per cent of particles as small as 0.1 microns. For allergen-carrying particles, which are often sub-micron in size, that distinction matters considerably — the difference between capturing them and allowing them to pass through is the difference between effective protection and a false sense of security.
Beyond filtration, the HushJet Nozzle projection ensures that purified air is projected across the room rather than cleaned only in the immediate vicinity of the machine, so the benefits of filtration are consistently delivered throughout the entire space.
Most people associate allergies with going outside. What’s the single biggest misconception about indoor air quality that you encounter?
A common misconception is that air pollution is primarily an outdoor issue. Dyson aims to break this myth by emphasising that indoor air can be up to 10 times worse than outdoor air due to pollutants like VOCs, PM2.5, and pet dander. Another myth is that sealing windows eliminates pollutants — Dyson addresses this by demonstrating how pollutants from cooking, cleaning, or even sitting on furniture can compromise indoor air.
Another prevalent myth is that pollution only impacts us when it is visible. Dyson challenges this by showcasing how invisible pollutants, such as nitrogen oxides, can be equally harmful, if not more so. Dyson’s sensors, capable of detecting these unseen dangers, work with advanced filtration to provide real-time protection. The belief that air pollution is a seasonal problem is another misconception Dyson addresses. Pollution is a 365-day challenge, with seasonal variations bringing different pollutants. For instance, PM2.5 levels can persist throughout the year, highlighting the need for continuous air quality management.