Maybe you live in the city, maybe you have a family member with asthma or other respiratory issue, maybe you have just realised how polluted our indoor air is and want to live in a healthier home. Whatever the reason, you have come to the conclusion that you need an air purifier. Or, wait, is it an air cleaner you need? What about an air filter?
It’s a minefield out there when it comes to the terminology, technology, effectiveness and variety of models that you can choose from. How do you know what’s right for you? Let me try to simplify a few things for you.
What’s in a Name?
Most manufacturers use the terms air cleaners and air purifiers interchangeably. Some refer to air cleaners as the products with a HEPA filter and purifiers as those that use Ultra Violet light, negative ions or ozone to clean the air. Often the devices use a combination of these with the ultimate goal of removing pollution- particles and gases – from the air.
So, the technologies available are:
1. HEPA Air Filter
Simply put, this is a fine mesh with flaps folded bit like an accordion, that traps particles as air is pushed through it by a fan. It can trap 99.97% of particles 0.03microns or larger. That includes pollen spores, pet dander, dust mites and some bacteria. This is a great option if you have an allergy sufferer in the house.
There is a bit of maintenance involved in that the filter has to be changed every two to three months or its effectiveness deteriorates. Some devices have a helpful indicator to remind you that the filter needs changing. Most HEPA filters also have a prefilter that removes larger particles and prolongs the life of the HEPA filter.
On the down side, a HEPA filter will not remove odours, chemicals or gases. For that you will need an activated carbon filter.
2. Activated Carbon filter
Interestingly, one of the first applications of activated carbon was to clean dirty water in the early 1900s. Subsequently it was used in gas masks to protect soldiers from poisonous gas in World War 1.
When carbon is activated it becomes porous like a sponge, creating tiny holes within the carbon where pollutants get stuck, never to be released. All sorts of problematic pollutants can be trapped by carbon – bad odours, chemicals, smoke – so they are particularly useful for people sensitive to poor air quality. For instance, those nasty VOCs that are released by new furniture, cleaning products or paints are eliminated nicely by activated carbon.
Maintenance is necessary and depends on the thickness of the filter as well as the nature of the pollutants. If cigarette smoke is the main pollutant, for example, the filter gets saturated faster and will need more regular changing.
Because a carbon filter isn’t especially effective at trapping particulate matter, they are often combined with a HEPA filter.
3. Ultraviolet Sterilisation
A UV sterilizer uses the same UVA and UVB rays emitted by the sun to kill moulds, bacteria and even some viruses. A UV purifier can work well in the kitchen or bathroom, where the heaviest bacterial load is.
4. Ionic or Electrostatic
These technologies have become a bit controversial as some may generate ozone. Ozone is harmless in small amounts but it’s crucial that you check how much a device produces as, if inhaled in large amounts it can be damaging, especially to the very young, the very old or those with respiratory illness. Avoid anything that creates more than 50-60 parts per billion. Look for certification marks for reassurance that your device is safe.
These purifiers work by producing negatively charged oxygen atoms which combine with dust, pollen or any positively charged ion and bonds with them. The resulting heavier particle then falls to the ground or, depending on the type of device, is trapped on a special collection plate. An ioniser therefore doesn’t eliminate or absorb the contaminants and so there is the potential problem of the particles becoming loose and re-entering the circulation.
An advantage of this type of purifier is that there is no filter and therefore no maintenance cost. If there is an ioniser plate, then this can simply be wiped clean and reused. This should generally done about once a week. These devices work against the smallest of particles including dust, pollen, bacteria and pet dander. They also tend to be low cost.
Size and Positioning Matters
While it may be tempting to invest in the less expensive devices, think first of your problem and your goal. A single activated carbon purifier may be the best solution for a smelly utility room but if your aim is to reduce allergy triggers for your family, then you must factor in your whole house. My kids typically throw their worn clothes on their bed (bedrobe!) or the floor (floordrobe!) so any pollen tracked in from outside is disseminated throughout the house. When we walk around, we stir up dust which then travels just about anywhere.
A single purifier will only clean adjacent rooms not connected by a door or wall. We spend most of our time in the kitchen, living room, bedroom, office and basement, so consider each individual room’s problems and its occupants before choosing the right device. Positioning can improve the function too- if its cigarette smoke, position your purifier where the ashtrays are. A purifier by the door can help filter air as it comes into the room. In general, keep the device in a place with high air flow to maximise efficiency.
Finally, in a living area where people are continuously coming and going a purifier must be keptrunning 24/7. In a room like a bedroom or office where the door can be kept closed, then it’s only necessary to run the machine when the room is occupied.
About Dr. Anna O’Donovan – Medical & Lifestyle Author
Anna is a mum of three children, one with allergies, and she suffers from allergies and asthma herself. She is a qualified doctor and worked as a General Practitioner and as a dentist for a number of years. She is also an award-winning author.
air care, indoor air, asthma, asthma triggers, allergy, allergy triggers, healthier home, HEPA, air cleaner, air purifier, air filter
Air Purifier Maintenance, Sylvane, Click Here
Air Purifiers: The Good, The Bad, and the Ugly. Click here
8 Best Air Purifiers For Your Home, Forbes, Click here