My PM levels are staying on 1 and won’t change. Is that correct? Abraham Gomez April 03, 2020 00:35 Updated If everything is clean, a PM indication of 1 should be correct. Related articles My Halo didn’t update to the latest version. How can I update my firmware to the latest version? The Halo readings look a bit off. Are they accurate? Comments 2 comments Sort by Date Votes K1478625 July 04, 2021 04:58 Hi, mine is rangebound in single digits despite presence of 2nd hand cigarette smoke in the vicinity, should we be expecting much higher readings then? 0 Abraham Gomez July 06, 2021 19:32 Hello, thanks for the question. How well ventilated is the space and do you use an air purifier? Either of those could contribute to lower-than-expected PM levels. However, you can also perform a quick test on the Halo. To do this, you can blow some smoke from a cigarette or match directly towards the Halo to see if the PM values change as expected. If they do, it's working properly. If not, please contact email@example.com, and one of our team members will be able to help you. 0 Please sign in to leave a comment.