Using an air purifier to reduce asthma and allergy triggers in your home
If you have asthma or allergies, it’s important to know that the air in your home can be 5 times more polluted in comparison to outdoor air. We explain how using an air purifier can reduce common asthma and allergy triggers and improve your home’s air quality.
Last updated 17 September 2025
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What are the major air triggers for asthma and allergies?
Dust mites, mould, pet dander, and volatile organic compounds (VOCs) are the major airborne triggers for asthma and allergies in the home. VOCs are chemicals that evaporate into the air at room temperature and can trigger allergic reactions.
Why do seasons matter for people with asthma and allergies?
Seasons are very important for people with asthma and allergies because there are different challenges at different times of the year in New Zealand.
In spring there’s an increase in pollen, and in autumn and winter there’s an increase in dust mites compared to other seasons.
In New Zealand the highest months of relative humidity are May, June and July. High humidity levels of 70 per cent and above provide an environment that is ideal for mould growth. An increase in mould in turn causes an increase in dust mites.
Pollen, dust mites and mould are all asthma and allergy triggers which may increase hay fever and worsen asthma symptoms in some people.
How can an air purifier help?
An air purifier assists people with asthma and allergies by drawing air in, taking particulate matter and various compounds, sometimes even viruses out of the air and then expelling clean air into the environment. It may reduce common asthma and allergy triggers in the home including dust mites, mould, pet dander, pollen and smoke. Some air purifiers have an activated charcoal filter which will remove VOCs/chemicals and gases.
What’s most important to look for in an air purifier?
Filter type
For people with asthma and allergies, the most important feature in an air purifier is the filter.
All Sensitive Choice approved air purifiers have a HEPA-13 filter that will filter out 99.97% of particles in the air, as tiny as 0.3 microns, to help you enjoy fresher, cleaner air.
An activated carbon filter is also beneficial. This type of filter contains either powder or granulated forms of carbon which absorbs chemicals and gases in the air.
Efficiency
Look for one that’s efficient and sized accordingly to the room. A small air purifier device will be effective at cleaning the air in a smaller room but would be less efficient when filtering the air in large spaces. Having a larger air purifier device will suit a larger space (like an open plan living room, or a massive lounge area) and will also be effective in smaller spaces.
Take into consideration how well sealed the room is. An air purifier will have much less benefit in a large room with frequently opened doors and windows than a smaller better sealed room.
Noise
Additionally, if you plan to have an air purifier in the bedroom it’s important to choose a device that functions quietly so you’re not disturbed or kept awake at night.
Do I need more than one in my home?
Air purifiers are useful wherever you are in your home, so it’s common to move them around from room to room. For example, having it in the bedroom at night and in the living room during the day. Some people choose to have standalone air purifiers in different rooms, so they don’t have to move them around.
Do I really need to change the filters?
Yes, you do. Material builds up on the air purifier’s filter as it is working. We recommend changing the air purifier filter in accordance with the manufacturer’s recommendations. This could be every 3, 6 or 12 months. The efficiency of the filter will reduce if the filter isn’t changed on a regular basis.
How do I know which air purifier to choose?
Sensitive Choice has already done all the hard work for you by rigorously reviewing products and services through an independent expert panel, utilising specialist knowledge and the latest research. All Sensitive Choice approved products carrying the Sensitive Choice blue butterfly logo have been identified as asthma and allergy friendly.
Keep your eye out for the Sensitive Choice blue butterfly while out shopping, and check out the following air purifiers and air purification technology approved in New Zealand by Sensitive Choice: