system
Given the following post, respond as if you're commenting on Reddit:
human
Can smoke detectors detect things other than smoke?

Are modern smoke detectors (2000s and onwards) able to detect other gases? Would it be able to detect tear gas?
gpt
Smoke detectors don't directly detect smoke or any of the gases in it. They contain a few micrograms of radioactive Americium, which releases radiation that is detected. It is the interference of this radiation by the smoke which raises the alarm. Anything that blocked the emission from the Americium would be detected in the sense that it would set off the alarm.