Clean Air Blog

Accurate PM2.5 measurement matters if you want to understand real-world air pollution exposure indoors. While many low-cost air quality monitors claim to measure PM2.5, actual performance can vary significantly between models. To better understand how different consumer-grade monitors compare, we looked at a group of commonly used models from Qingping and Temtop. Rather than relying only on manufacturer claims, we anchored our comparison to models with independent field test data, then examined how closely the remaining units tracked alongside them in real indoor conditions. All six monitors were co-located on the same bench and run continuously over several days. While absolute readings varied slightly, the overall patterns and trends moved together closely, with relatively small gaps between devices. This provides useful context for how these monitors behave in practice, particularly when used to track changes and spikes in PM2.5 rather than focusing on a single absolute number. Independent Testing Anchors Southcoast AQMD, based in California has a program where they compare air quality monitors with high grade reference equipment. This provides independent test data for dozens of models, from low cost ones like the QP Lite to ones costing thousands of dollars. For PM2.5, all the results are published here. Several units already have results available from Southcoast AQMD. All showed strong correlations with the reference equipment for PM2.5 measurements, and low mean errors - often beating monitors costing thousands of dollars!  Model Field R2 (Correlation) Field MAE (Absolute Error) Qingping Lite 0.85 to 0.93 1.8 to 3.6 Qingping Pro 0.86 to 0.90 1.8 to 2.3 Temtop LKC-1000S+ 0.91 to 0.92 3.1 to 3.6 Note, original model of Pro and Temtop LKC were tested, updated models used for our comparison testing. Why PM2.5 Matters PM2.5 are tiny particles that can reach deep into the lungs and even the bloodstream. When air pollution is talked about, it typically refers to levels of PM2.5, due to the serious health impacts. In New Zealand, indoor levels can often be higher than outdoors. Seeing the levels and changes in your home or workplace can help you decide if interventions such as ventilation or air purification is required.  What we tested   Models: Qingping Lite, Qingping Pro 2, Temtop M10i, Temtop M10+, Temtop S1+ and Temtop LKC-1000S+ 2nd. Environment: Same bench in an apartment (Christchurch), co-located and away from air vents. Period: 14 - 18 August 2025, hourly measurement results Objective: Check how closely the models track together in real conditions, using indepdently tested units as the benchmark Method and limitations Recording frequency: We aligned measurements to the unit with the lowest recording frequency (M10+), so all results are reported hourly.  Time adjustments: Not all units were recording exactly on the hour, so the closest recording to the hour was used. In some cases this was 5mins before or after the hour. Units plugged in: All units were plugged in to ensure regular readings and updating PM2.5 Exposure: Two spikes occured due to cooking with the frypan. No air cleaning was used, in order to keep levels high for longer. Results By the numbers Most pairs have correlations between 0.95 and 0.99, indicating very high levels of correlation Typical difference: Around ~1 µg/m³ when averaged over the period Mean reading: Small spread across devices, mean PM2.5 reading for the each device across the entire period was between 3.2 and 5.0 µg/m³. Variances observed during initial PM2.5 spikes, due to timing of readings. A note about PM10 One of the reasons we focus on PM2.5 is that PM10 numbers from low-cost optical sensors are generally less reliable than PM2.5. This is shown in the Southcoast AQMD results, where PM10 accuracies were always quite a bit lower than for PM2.5. This essentially boils down it it being more complex to measure for PM10 sized particles. If you'd like to learn more, there's a great writeup about this here.

It's hard to beat the aroma of garlic or steak sizzling away on the frypan as it fills your kitchen with flavour. But under those delicious scents lies fine particles called PM2.5, that can travel deep into your lungs and affect your indoor air quality. In a test in a Christchurch apartment in May 2025, cooking on a front burner pushed PM2.5 levels throughout the apartment into the hazardous range, even with the rangehood set to full power. In this article we'll show you exactly how we measured those spikes, how bad it got and how much of a difference using Air Purifiers made. Armed with this information, you can ensure you keep your air clean, whatever you're cooking! Figure 1: Rough Layout of Apartment + Positions of Monitors and Purifiers First Test: Baseline (No Air Cleaning) This experiment actually started accidentally, after noticing the air quality as measured on my QP Pro units was at very concerning levels. It turned out that even at full power, my rangehood barely captured smoke from the front two hobs. This is definitely a bit of a surprise given this is a relatively new apartment.After frying for about 15 minutes, it seemed a little hazy and smokey inside. I checked my air quality monitors in both the lounge and separate bedroom, and both showed very high readings! With PM2.5 counts of over 300 µg/m³, you really want to limit your exposure to this. For perspective, this is about three times higher than the average pollution level in Delhi, and is well into 'hazardous' air quality levels.  If you stop cooking, you immediately remove the PM2.5 source. But on a chilly day with windows closed, those particles can linger for hours. While the rangehood extractor fan was used, it hadn't effectively drawn out the cooking smoke. Being a chilly day, no windows or doors were opened. Here is how the air quality looked over the evening: Figure 2: PM2.5 Readings in Bedroom and Lounge from Cooking Note: PM2.5 to air quality ratings sourced from EPA AQI breakpoints. As you can see, the PM2.5 levels shot up very quickly when the cooking started. For several hours the air quality was at or above unhealthy levels, even lingering at hazardous amounts for awhile! What does this mean? Basically the equivalent of smoking about 1.3 cigarettes! Definitely not something you want to be regularly exposed to. Especially if you have asthma or other breathing sensitivities. Second Test: With Air Purifiers This time, our accidental experiment was repeated with one key tweak, switching on air purifiers when the concentrations peaked. The apartment is well covered on that front, with a Smart Air Sqair in the bedroom and a Smart Air SA600 in the main living/kitchen area.You'll notice from the layout graphic earlier, we've also placed the purifiers away from the air quality monitors. This helps ensure the readings are representative of the actual air quality in the apartment, and not just the air quality around the purifier.Now the big reveal, how much of a difference can the air purifiers make? We allowed the PM2.5 concentrations to reach similar levels to our baseline test, and then turned both purifiers on at their max power settings. Figure 3: PM2.5 Readings in Bedroom and Lounge from Cooking, using Air Purifiers The outcome? In just 30mins, PM2.5 concentrations had dropped by over 90% - this is compared to between 25% and 29% when we didn't use them. Air quality reached the optimal 'Good' level within 45mins in the bedroom and within 1 hour in the main living area!Why are these air purifiers so effective at removing cooking pollutants and smoke? It's all thanks to the combination of HEPA filters and high Clean Air Delivery Rate (CADR).  The HEPA filters on both units are very effective at absorbing harmful particulate matter in the air, such as from frying and smoke. However, a good HEPA filter won't do much if the purifier isn't able to send much air through it. With CADRs of 315m³/hr and 500m³/hr respectively, the Sqair and SA600 are able to push significant amounts of polluted air through their filters. This makes them best in class when it comes to how effectively they purify air. As you can see, we can back this claim up with real data! Smart Air Sqair Smart Air SA600 Stylish, powerful and quiet at a great price. Perfect for the bedroom, or any space up to 43m². Dual inlets with filters on each side. Serious cleaning power for larger spaces up to 60m², while remaining quiet. Other air quality measures you can take: Ensuring your rangehood is working effectively will certainly help reduce the amount of PM2.5 in the air. Mechanical ventilation i.e. HRV/DVS etc if you have it. This will bring in air from outside or the roof space which should be much less polluted. Finally opening windows and doors to let a breeze through, even if for just a short while will also quickly help lower the amount of pollutants.

Like many Kiwis, I used to never give a second thought to the air I'm breathing. Our landscape isn't covered in polluting factories or coal plants and we're known for our (relative) clean air. However, after learning more about indoor air quality, I decided to start monitoring the air inside and was surprised by what I discovered! How do you Monitor the Air? While it's not an uncommon thing to do overseas, monitoring air quality is still something not many Kiwis are familiar with. While it's possible to pay professionals to come in and do a detailed report, there is a much easier (and cheaper) way. Enter the Indoor Air Quality Monitor, a device with sensors to measure air quality issues such as PM2.5, CO2, VOCs and more. For the past 2 years I've used a QP Lite, QP Pro and Smart Air CO2 Monitor to keep tabs on the air in my home. With an affordable price, high accuracy and data download ability, they're some of the best options on the market. First Surprise: CO2 Levels While Sleeping Like many of us, I took it for granted that sometimes we'll wake up feeling groggy, tired and maybe with a bit of a headache. While there are many possible causes for this, have you ever considered CO2 might be behind it? Bedrooms are small spaces and if you close the door and windows, where does fresh air come from? As we breathe oxygen is converted to CO2 and without ventilation the levels can rise surprisingly fast! Especially if you have a partner in the same bedroom. CO2 levels are reported in parts per million, with outdoor air being around 420ppm. Once the air reaches 1000-2000ppm you'll typically experience drowsiness and from 2000-5000ppm headaches and other complaints can occur. I was very surprised to see the levels for my bedroom at night regularly reach over 3000ppm! Once I improved the ventilation, I noticed I'd wake up feeling less groggy and more alert.  Below is an example comparing relatively good ventilation in a bedroom (initially) then poor ventilation later in the week. You can also see just how quickly the CO2 levels drop when ventilation is introduced (opening the door) in the morning! CO2 Concentration Levels: Measured with Smart Air CO2 Monitor Second Surprise: VOC Levels in a New Apartment Having moved into a newly built apartment for a period of time in 2023, I found the 'new building smell' very powerful and I would often get headaches. Unfortunately this is a common experience for many new home owners, as the off gassing from paint, flooring and fabrics etc. produces VOCs like Formaldehyde and Benzene. These can cause symptoms like headaches, respiratory issues, dizziness and throat irritations. There was a sharp increase in average VOC levels reported on my QP Pro after moving into the apartment, compared to an older existing house.  Previously, measurements were around 0.3-0.4 mg of TVOC per m³. In the new building, it was 10 times higher and would be between 3 and 4mg per m³. This puts it in the potentially dangerous threshold. Luckily there is action that can be taken to help reduce these levels. The most effective measure is introducing fresh air by opening doors and/or windows. You can also achieve this with mechanical ventilation. If neither of these options are possible, consider an Air Purifier with Activated Carbon Filter. Here are some readings from the apartment showing the slow rise of VOC levels, then how quickly they get eliminated by opening windows and allowing a breeze through! TVOC Concentrations: Measured by QP Pro Air Quality Monitor Third Surprise: PM2.5 Levels from Vaping While there has been a surge in vaping in recent years, we're still learning about its potential impacts. Having lived with someone who vapes in their room, I've been able to see how it impacts on air quality - especially when ventilation is limited. While it produces a fine mist and sends chemicals into the air, the process of vaporising the liquid also sends particulate matter into the air, including harmful PM2.5. To learn more about PM2.5, see the below video: While I wasn't surprised to see vaping having an impact on air quality, I was surprised at just how high the PM2.5 levels would get - even while in a different room. We've had reports from some of our customers about being impacted by others in their household vaping, which isn't surprising given these results! On the plus side, levels do drop fairly quickly back to normal once the vaping stops. However, peak concentrations ended up at levels you'd see in the most polluted cities in the world, at their absolute worst! The below graph shows the levels of PM2.5 measured from an adjacent room to the one being vaped in. PM2.5 Levels: Measured with QP Pro Air Quality Monitor: Wrapping Up Ready to make your own discoveries in air quality? We've got you covered with accurate and affordable CO2 monitors!

Whether it's moving into a new home or doing some DIY renovations, many of us will be familiar with that 'new home smell'. Unfortunately, behind that smell are a number of potentially dangerous chemicals or VOCs such as formaldehyde! For some this may cause headaches, dizziness and other health issues. This brings us to the question: How do you keep yourself safe from these VOCs and can an air purifier help? The good news is there are ways to mitigate these VOCs and the right air purifier can definitely help! Understanding VOCs and Their Sources VOCs are emitted as gases from certain solids or liquids. Common sources in new builds and renovations include: Formaldehyde: Found in building materials like plywood, particleboard, and adhesives. Benzene: Emitted from paints, glues, and cleaning products. Toluene: Present in paints, paint thinners, and adhesives. Health Impacts Exposure to VOCs can cause, amongst other things: Headaches Dizziness Respiratory issues Eye, nose, and throat irritation Monitoring VOC levels with an Air Quality Monitor Using an air quality monitor with a TVOC sensor, like the QP Pro 2 or the Temtop M10 can help you gauge VOC levels in your home. While you won't see levels of each specific chemicals, measuring the VOCs will help give a picture of baseline levels of VOCs in the air and can show the effectiveness of different tactics in reducing VOCs. Effective Strategies for Reducing VOCs Ventilation The most effective way to reduce VOCs is through ventilation: Mechanical Ventilation: Use exhaust fans or air exchangers like HRV systems. Natural Ventilation: Open windows and doors to create a strong cross breeze. Formaldehyde Cookouts These are a way to force more formaldehyde from building materials, furniture etc. in a shorter period of time. Note you should avoid being inside when the cookout is run. Smart Air have written a detailed guide here, however the basic process is: 1. Close windows/doors and increase temperature, through heating or naturally with sunlight. Aim for 30+ degrees if possible. 2. Keep the temperature up for a few hours, ideally 6-8 if possible. 3. When you return, open windows and doors to remove the formaldehyde from the air and return the space to a normal temperature. 4. Repeat this several times  Air Purifiers with Activated Carbon Filters An air purifier with a carbon (VOC) filter can provide additional assistance, especially when ventilation isn't possible. Key Factors to Consider: Amount of Carbon: This determines the amount of VOCs which can be filtered before the filter becomes saturated. Some mesh-style "carbon filters" may last only a few minutes in high VOC environments. Separate Carbon Filter: Allows for easy replacement when needed, as in high VOC situations the Carbon Filter will likely need replacing well before the HEPA filter. Our Recommended Purifiers: Sqair: 140g of activated carbon per filter. SA600: 170g per filter (2 per purifier). Blast Mini: 550g of activated carbon per filter (optional extra). Blast: 0.9kg of activated carbon per filter (optional extra). For additional VOC cleaning power, you can remove the HEPA filter and use multiple carbon filters in our purifiers.   Wrapping Up VOCs are an unfortunate reality in newly built or renovated homes. It's essential to tackle these to maintain good indoor air quality and health. Ventilation, both mechanical and natural, is the most effective strategy. Additionally, using air purifiers with plenty of activated carbon can provide assistance, especially when ventilation is not possible. Formaldehyde Cookouts are an additional tool to help lower the levels of formaldehyde being released.

Air quality is an essential but often overlooked aspect of our well-being. In New Zealand, many remain unaware of how winter weather can profoundly affect the air we breathe. The Unseen Winter Culprit Winter air pollution in New Zealand is mainly shaped by weather patterns and heating choices. In the colder regions, while less common than previous years, we still see fireplaces being used for warmth. These emit particulate matter; tiny harmful particles into the air we breathe. Even though recently there have been tightened standards as far as emissions from these, they've focused on reducing the larger PM10 particles. The levels of PM2.5 seen in the air however, frequently exceed WHO recommendations. Inversion Layers: A Winter Phenomenon The New Zealand climate significantly influences air quality. In winter, many areas experience cold, still nights. These conditions, along with geographical features like mountains, create 'inversion layers'. This traps cold air and pollutants close to the ground, boosting harmful particle levels. We commonly see these occur in valleys and parts of Canterbury, Otago, Southland and Marlborough. Inversion layers occur when a layer of warm air sits on top of cooler air. This is the reverse of what we normally see where air gets cooler at higher elevations. This "lid" traps pollutants, contributing to higher PM10 and PM2.5 concentrations. PM10 and PM2.5 are particulate matter, or tiny particles in the air. PM10 particles are less than 10 micrometres in diameter, and PM2.5 are smaller, less than 2.5 micrometres. The tiny PM2.5 particles are concerning, as they penetrate deep into the lungs and bloodstream. Health Implications of Poor Air Quality Air quality influences our health. Both PM10 and PM2.5 pose health risks. The smaller PM2.5 particles, which can infiltrate our respiratory system, exacerbate conditions like asthma and COPD and can contribute to heart disease and lung cancer development over time. The World Health Organization states PM2.5 exposure can lead to respiratory and cardiovascular issues, hospital admissions, and mortality from cardiovascular and respiratory diseases and lung cancer. Understanding air quality's link to health is vital, especially for those in colder New Zealand regions, where winter pollution can be harmful. Pollution levels in these areas can reach unhealthy and even very unhealthy levels at times. Measures to Improve Air Quality As we gear up against winter cold, we can also protect ourselves from air pollution. Monitor the Air Quality Understanding the air quality in your area is important. In many countries checking the air quality is as common a task as checking the weather. Monitoring can help us make informed decisions about when to go outside and for how long during poor air quality periods. LAWA (Land Air Water Aotearoa) has a great air quality dashboard which can tell you more about the trends in your area. For live air quality monitoring check out the aqicn website. It can also help to monitor your indoor air, as outdoor pollutants can seep into your home. Personally, I found in my Christchurch home that during cold winter nights the air inside my home would often reach unhealthy levels due to the pollution. Want to check if the same happens to you? We have affordable and high accuracy air quality monitors available on our website. Air Purifiers and Filters Quality air purifiers can remove harmful particulate matter from your home's air. Opt for purifiers with HEPA filters to remove PM2.5 particles. We provide a range of proven, affordable and effective air purifiers from Smart Air. Clean Heating Cleaner heating options can improve air quality. If possible, consider shifting from wood burners to cleaner heat pump options. Wrapping up Awareness is the first step in enhancing our winter air quality. The more we understand, the better we can protect our health and communities. Stay informed, take action, and breathe easier this winter.

Maintaining good indoor air quality is an important and often overlooked aspect for your health and well-being. With the right strategies and tools, you can significantly improve the air you breathe inside your home. Understanding Indoor Air Quality We've written a post which goes into detail about indoor air quality which you can read here. However for a quick reference, Indoor air quality (IAQ) refers to the condition of the air within and around your home. Poor IAQ can lead to health issues such as allergies, asthma, and respiratory infections. Common indoor pollutants include dust, pet dander, mould, volatile organic compounds (VOCs), and particulate matter (PM). Simple Steps to Improve Indoor Air Quality   1. Ventilation: Open Windows: Regularly open windows to let in fresh air and reduce indoor pollutant levels. Exhaust Fans: Use exhaust fans in kitchens and bathrooms to remove moisture and pollutants. 2. Air Purifiers: HEPA Filters: Invest in air purifiers with HEPA filters to capture fine particles and allergens. Activated Carbon Filters: These are excellent for removing odours and VOCs. When it comes to selecting an air purifier, consider factors like room size, CADR and noise levels. We've detailed everything you need to know in a guide here. 3. Humidity Control: Dehumidifiers: Keep humidity levels between 30-50% to prevent mould growth. Houseplants: Certain plants can help maintain indoor humidity and filter air. 4. Regular Cleaning: Vacuuming: Use a vacuum cleaner with a HEPA filter to reduce dust and pet dander. Dusting: Frequently dust surfaces to minimize allergens. 5. Avoid Indoor Pollutants: Smoke-Free Home: Prohibit smoking indoors to avoid harmful chemicals. Natural Cleaning Products: Use natural or non-toxic cleaning products to reduce VOC emissions. Monitor the Air with an Air Quality Monitor Features: Look for monitors that measure PM2.5, CO2, temperature, and humidity. Smart Integration: Choose devices that connect to your smartphone for real-time monitoring and alerts. Accuracy: Research the accuracy, as the very cheap ones tend to be wildly inaccurate. By using high-quality sensors, air quality monitors provide accurate data to help you understand and manage your indoor air quality effectively.  We have a small selection of Air Quality Monitors chosen due to their accuracy and affordability, making it easier to maintain a healthy environment. Wrapping Up Improving your indoor air quality is a key for maintaining a healthy living environment. By adopting these strategies and using the right tools, you can ensure that the air in your home is clean and safe to breathe. Want to learn more about air quality, air quality monitors or air purifiers? Keep browsing our site or get in touch!