When HN users recommended it
1 HN user recommended this in 2020, in one comment.
20072026
Each tall tick is one HN user's first recommendation. A short tick is the same user again. Click a tick to jump to the comment.
1 HN user recommended this in 2020, in one comment.
Each tall tick is one HN user's first recommendation. A short tick is the same user again. Click a tick to jump to the comment.
This is a good quality particle counter for a home or school:
https://www.amazon.com/Dylos-Laser-Particle-Counter-DC1100/d...
It can be connected to a computer to record particle counts long term using the included Windows software. Useful for seeing that your Hepa air purifier is actually working. There are many brands of hand held instruments for use with HVAC systems. Their cost ranges from $100 on eBay up to several thousand dollars for high end instruments that can measure many particles sizes. They generally are not meant to be left on to take measurements over days though. There are also professional weather instruments that use a laser to count particles in the air outdoors.