I have acute allergy triggered asthma; could you recommend an affordable air q meter for pm2.5 and pm10 that isn’t interpolated?

Hi. I have very severe allergic responses that trigger asthma relating to pollen dust and mould in particular some chemicals too. It’s incredibly difficult to manage and I’m housebound but that’s not enough. I was wondering if you get a moment if you might be able to advise me on a meter to buy to go alongside my purifiers now I know that their sensors expire, I have two Philips 3000 series purifiers. I’m reliant on masks and medications also.

I have seen that sensors measuring pm10 at a cheaper level interpolate and as I’d read dust and mould can fall under pm10 I don’t know if there’s an affordable sensor that would be reliable for pm10 as we;l as pm2.5. I’m in the uk

Hi @Zuki,

Thanks for joining! I hope we are able to help :slight_smile:

I’m not sure what you mean by expire, the the sensors should continue to work. However, the sensors used in air purifiers often aren’t ideal (not necessarily because they’re bad - in many cases they same ones are found in air quality monitors - but generally because there’s less science behind them and their placement isn’t ideal).

Unfortunately, PM10 is tough, and I don’t know of any air quality monitors that are particularly accurate with these larger particles. I checked the AQMD AQ-SPEC database, and even here there aren’t really any decently accurate PM10 monitors at a reasonable cost. The PurpleAir PA-II (an outdoor monitor) did perform well, but their recent models appear to be a lot worse in this regard.

I will continue to look and let you know if I find anything! It’s frustrating that PM10 is so hard to measure!

Hi, thanks for replying. When I said expire, I meant that sensors all have a lifespan and most fall within 3 years maybe 5. The sensiron ones are 10 sometimes at least. They just become inaccurate and wear out over time - I’m not sure how that plays out exactly but it was one of the surprises for me in researching that you may as well get a cheaper device with one of these sensors rather than an extremely expensive one from this perspective.

I know some sensiron ones have a self cleaning thing that helps improve lifespan. But the plantower are often just 3 years. I have seen on a reddit thread reps from both of these companies very openly and fairly speaking about this.

For anyone else who may look at this as well as yourselves I have been speaking with dylos and was told that they are able to make a device calibrated toward much larger particles although it will cost a few hundred dollars more to do this. I’ll try to find out more.

Hi @Zuki, apologies for the late reply - I’ve been travelling the past few days and didn’t have a chance to check in.

Ah, okay, I understand what you mean. Yes, most sensors are between 3-5 years, and Sensirion advertises 10 (but we haven’t actually see this yet, as the sensors that advertise this were only released a few years ago and haven’t yet proven themselves in these cases). You’re also right about the pricing, since most more expensive monitors use the same sensors, you can get very similar performance in devices across vastly different price ranges.

To be honest, it’s hard to find many studies on the accuracy of the Sensirion SEN55 (and other SEN line models) so I’m still partially on the wall about them - even though I do like their technology. On the other hand, the Sensirion SPS30 looks to do quite well in most studies and it also offers the same 10-year lifespan I believe. Assuming they use the same tech, I think Sensirion PM sensors are generally quite good for the price. If longevity is of a lot of importance to you, I would recommend going for a device with a Sensirion sensor or at least getting a device with a replaceable PM sensor (PurpleAir, AirGradient, and Qingping AQM Gen 2 all come to mind).

This sounds very interesting - which device are you look at calibrating? I would love to hear more, and depending on how your experience is, I might even look into getting one for a review!