几年前，如果想购买一台精度较高的PM2.5空气质量监测仪要花费数千美元。
近年来，各类高性价比空气检测仪产品层出不穷。那么，低成本的空气质量监测仪到底能不能准确测量出PM2.5的数值呢？
Smart Air最近测试了QP Pro和QP Lite空气质量监测仪，接下来，我们让数据说话。
青萍：空气质量一目了然
青萍Pro是一款小巧便携的空气质量监测仪，可测量PM2.5，PM10，tVOC，CO2，温度和湿度。
高清显示屏，轻松地查看室内空气质量。
青萍Lite是QP Pro的mini版，Lite可以测量PM2.5，PM10，CO2，温度和湿度。它比市面上绝大多数的空气质量监测仪更小更轻，充满电后可以待机超过8小时，非常适合在外出携带。
阅读更多：什么是tVOC，tVOC传感器是否准确？
我们如何测试QP空气质量监测仪
我们将青萍Pro和青萍Lite空气质量监测仪放置在北京Smart Air办公室外。
距离东城东四的政府PM2.5监测仪约800米。
在17天的时间里，我们记录了两台监测仪的数据以及官方PM2.5监测数据。
同时我们还测试了另一台监测仪 ： IQAir AirVisual，它在上一轮空气质量监测仪测试中名列前茅。
以及镭豆空气质量监测仪。
然而，从镭豆的收集数据存在问题，在最后的对比中删去了镭豆 （稍后会详细介绍）。
测试结果
为期17天的测试中，官方数据显示PM2.5浓度分布在6-60 μg/m³之间。
准确性
所有参与测试的空气检测仪（青萍Pro，青萍Lite，AirVisual）都与政府显示器具有较强的相关性，下图显示了三台检测仪与政府数据的相关性。
平均偏差
三台检测仪在相关性上都表现良好，但青萍Pro读数最接近官方显示器，青萍Pro平均偏差为7.9微克，青萍Lite为8.9微克，AirVisual为10.8微克。
青萍空气质量监测仪与镭豆监测仪相比如何？
镭豆空气质量监测仪在之前的空气质量监测仪测试表现出来的准确性仅次于AirVisual。
与昂贵的同类产品相比，青萍的精确度令人印象深刻
青萍空气质量监测仪比市场上一些相当昂贵的空气质量监测仪(价格超过50倍)表现出了更强的准确性。
数据显示，低于200美元的QP监视器的表现明显优于AQMesh（7800美元），Naneos Partector（7000美元）和Met One E-SAMPLER（5500美元）。
与空气净化器类似，价格更高的空气质量监测仪并不意味着性能更好。
数据注意事项：注意湿度
很多外部因素都有可能会影响空气质量监测仪的准确性，例如湿度和测试点附近的空气污染源。
我们这次的测试地点位于北京繁忙的东城区，来自汽车的污染可能会影响读数，导致某些数据与官方数据的相关性较低。
测试期间的室外湿度约为65%，略高于室内湿度（30-50%）。
如果在室内更常见的低湿度水平下进行测试，那么所有空气检测仪可能会表现出更高的准确性。这也许可以解释为什么我们之前的测试显示与官方数据的相关性更高（超过0.90，而这次为0.75）。
公开数据
Smart Air公开测试时的所有数据，可以免费下载。
青萍空气质量监测仪准确吗？青萍 Pro和青萍 Lite的表现都优于Smart Air之前经过测试的空气质量监测仪IQAir Air Visual，同时青萍 的性价比更高。
青萍空气质量监测仪准确吗？
青萍 Pro和青萍 Lite的表现都优于Smart Air之前经过测试的空气质量监测仪IQAir Air Visual，同时青萍的性价比更高。
Hello, thanks for you text and your work to evaluate the pm 2,5 sensor. I just bought an sensirion SPS 30 sensor and, so far, the data just don’t match with AirNow data that is at 3 km from my house. Maybe something is wrong with the way i use the sensirion, because it is new for me. Anyway I decided to ordre another sensor, the Piera Systems IPS-7100 evaluation kit. I would be interested to know if you’ve tested theses sensor (piera and sensirion)
Hi L’Evangeliste! Song here. We haven’t tested the sensor you mentioned, but I’ll definitely convey your suggestion to our engineers.
How do you recommend calibrating the QP Pro? Were we live (Taipei) humidity tends to be high most of the time. Does this affect tVOC readings? We noticed them being all over the place (fluctuating from 0.005 to sometimes 4.000+) even with no changes in location (bedroom) or environment (no use of chemicals, moving of furniture, etc).
Cool, I wanted to replace the Laser Egg with the QP FOR THIS VERY REASON, the Egg does the same. Even with closed windows and all 4(!) of my air filters on full blast for half an hour, it still says I’m supposed to be dead due to the lethal amount of VOCs in my room. Yeah, I’m not buying it. Tried to “recalibrate it” but it didn’t help in the slightest. I’m not even using the “AQI” reading anymore (since that includes the erroneous VOC numbers), only the PM2.5, that’s at least *usually* OK, but 1 out of the 3 Eggs also shows bogus readings occasionally… In any case, apparently the QP is also completely useless for VOC monitoring, so the search continues. Ouch.
You’re spot on Viktor – the VOC readings of the Laser Egg and QP both aren’t that useful on their own. We’ve covered this previously in our articles, but trying to measure VOCs just isn’t that useful – the air is full of hundreds of thousands of different VOCs, some that are harmful to us (in fact, we even breathe out VOCs!). Without going to a lab, there’s no way to measure only the ‘harmful’ VOCs like formaldehyde, so the best we can do is get an overall picture of all the VOCs in our room. In general, we shouldn’t be too concerned with the specific number of VOCs read by one of these devices, but use it as a general indication of how well-ventilated our air is.
If you do manage to find a VOC monitor that can only detect the harmful VOCs, then let me know. I’d be interested to find something like this that would seamingly defy chemistry!
It’d be interesting to see how the Qingping compare to the other CO2 monitors that were tested last year. Given enough accuracy I could just buy one of the QPs rather than buying 2 separate monitors.
Can you please explain why you are rating these QP device against the IQAir, knowing you’ve rated the later as relatively in average in your Best PM2.5 Air Quality Monitors in 2022 done in 2021 ? Why not rating it against “The best” / cheaper than tha IQAir ? Thx for your clarification.