This is a DIY open source air quality monitor starting from $67, a lot cheaper than what the article mentions: https://www.airgradient.com/open-airgradient/kits

This is a DIY open source air quality monitor starting from $67, a lot cheaper than what the article mentions: https://www.airgradient.com/open-airgradient/kits/ https://www.airgradient.com/open-airgradient/kits/ Been geeking out on AQ (air quality) lately and it’s fascinating. Market is very messy though. Few options with huge price discrepancies. Ultimately it looks like the sensors inside the fancy $300+ monitors cost a few dollars to acquire.