STEM与日常科技·英语30篇（7）

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空气质量监测仪如何无需实验室设备检测PM2.5颗粒

Portable air quality monitors detect PM2.5 particles using laser scattering principles instead of lab-grade filters.
A tiny laser beam shines through an air sample chamber where particles pass one by one.
Each particle scatters light at angles that sensors measure to estimate its size and concentration.
Algorithms compare scattering patterns against known standards for PM2.5, PM10, and pollen.
Temperature and humidity sensors correct readings because moisture affects particle behavior.
The device updates measurements every six seconds and averages them over ten minutes for stability.
Battery-powered units use low-power processors to run these computations continuously.
Manufacturers calibrate each unit against reference instruments before shipping to ensure accuracy.
Consumer models trade some precision for affordability but still meet WHO guideline thresholds.
This real-time insight helps people avoid exposure during wildfire smoke or traffic pollution peaks.