What does PM2.5 mean and is it dangerous?

Anula Wiwatowska
Jul 02, 2024
Icon Time To Read3 min read
// Not just a field on an air purifier's spec list

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Anytime air quality drops you hear a lot about PM2.5. It's thrown around in the news, it is slapped on to air purifiers, but what does PM2.5 actually mean, and why does it matter? In short, PM2.5 refers to particle matter that has a diameter of 2.5 micrometres or less. Bushfires, dust, and pollution can increase the density of these particles in the air, leading to short and long-term health risks.

In this guide we look at the longer version of that answer. We’ll break down what you need to know about PM2.5 including where it comes from, the risks, and how to limit your exposure.

What is PM2.5?

PM stands for particulate matter, while the number refers to the size of these particles;  PM10 has a diameter of 10 micrometres or less, while PM2.5 is 2.5 micrometres (0.0025mm) or less.

These airbourne particles can be made up of a bunch of components ranging from pollen and mould spores, through to soil, organic chemicals, metals and more. However the most common source of contamination is smoke from car and truck exhausts, industry, and from fires. During bushfire season we tend to see a higher concentration of PM pollution which can have immediate and ongoing health effects.

Why are PM2.5 particles harmful?

PM2.5 particles are airbourne and small enough to enter the body through regular breathing. In fact, they are so small that they can penetrate the lungs, enter the bloodstream, and affect the heart.

Exposure to high levels of PM2.5 for just one day have been linked to eyes, nose and throat irritation, asthma attacks, respiratory symptoms, chronic bronchitis, and heart attacks in people with heart disease. While prolonged exposure for months and years can increase the risk of asthma, heart disease, premature death, and even affect fetal growth in pregnant people.

How to limit PM2.5 exposure

It is impossible to prevent exposure to PM2.5 particles but you can limit it. Since fire and smoke are such large contributors, the best advice is to monitor how much time you spend around them.

Some easy steps are to cut out the use of wood-fired stoves and heaters, limit candles and incense in the home, don’t smoke cigarettes (or at least don’t smoke them inside), and use the exhaust fan above your gas cooktop. On smokey days, you should also keep your windows and doors closed and try to stay inside as much as possible, and wear a mask if you do have to leave the house. Just make sure it is a certified PM2.5 mask with a removable filter or an N95 (you may still have some of these laying around).

Gas heaters can also emit PM2.5 particles, but these are much lower than anything that puts out smoke. Regardless it is better to avoid unflued indoor gas heaters (for both PM2.5 and carbon monoxide reasons), or if they're being used make sure you're following the safety protocols.

When it is clear out, throw open the doors and windows to remove indoor pollutants and any moisture build up. In particularly moist areas like laundries and bathrooms, use the exhaust fan to circulate the air to help fight against mould and move any particles out of the space.

It may also be worth investing in a good quality air purifier that has a HEPA 13 filter, capable of filtering out PM2.5 particles. Most high end air purifiers are equipped with this kind of filter, and even some budget devices like those from Kmart. But some cheap options like the Ikea range are only EPA certified so they won’t do much to protect your lungs.

How to check the PM2.5 levels

Luckily there are plenty of resources out there that help you keep track of the PM2.5 levels.

All state governments use a similar system for tracking the air quality index. Across the country different state governments rate the air quality from Good, through to Extremely Poor on a hourly basis. In many cases these are split into districts, and show everything from PM2.5 ratings, through to carbon monoxide, ammonia, and sulfar oxide.

Here are the best links per state;

Indoors you'll need to get your own air quality sensor to be able to keep tabs on your PM2.5 levels. Most air purifiers have a built in sensor, but you can also buy them as standalone devices if you'd prefer. These tend to give you other information like humidity levels, temperature, and even if formaldehyde is in the air.

Here are some options;

Eve Room
Eve Room - Indoor air Quality Sensor to Monitor air Quality (VOC), Temperature and Humidity, Apple HomeKit Technology, Bluetooth, Thread
From
$152.35
Works with:
Apple Home Kit
Measures:
Humidity
VOCs
Temperature
Nurdo 9 in 1
Nurdo 9 in 1 BT Air Quality Monitor CO2 Meter Carbon Dioxide Detector
From
$47.98
Works with:
iOS
Android
Measures:
Humidity
PM1.0
PM2.5
PM10
Temperature
Staright Tuya
Staright Tuya WiFi Intelligent Air Housekeeper 6-in-1 Air Quality Monitor
From
$45.51
Works with:
iOS
Android
Measures:
PM2.5
Formaldehyde
TVOC
Carbondioxide
Temperature
Humdity

Air purifiers that filter PM2.5

Australia has a lot of air purifiers on the market, brands range from Philips, to Samsung, and of course to Dyson. Each of these air purifiers are capable of filtering out PM2.5 particles indoors across their noted coverage. If none of these work for you, then look out for air purifiers with 99.97% filtration noted in their specs.
Anula Wiwatowska
Written by
Anula is the Content and Social Media Editor within the Reviews.org extended universe. Working in the tech space since 2020, she covers phone and internet plans, gadgets, smart devices, and the intersection of technology and culture. Anula was a finalist for Best Feature Writer at the 2022 Consensus Awards, and an eight time finalist across categories at the IT Journalism Awards. Her work contributed to WhistleOut's Best Consumer Coverage win in 2023.

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