Integrated Virtual Impactor Enabled PM2.5 Sensor

As more and more proofs show that fine particles (diameter of <inline-formula> <tex-math notation="LaTeX">$2.5~\mu \text{m}$ </tex-math></inline-formula> and below) pose more risk on human health than coarse particles, an increasing need for monitoring fine particles has emerged. A miniaturized sensor designed for measuring fine particle concentration is presented in this paper. The proposed sensor possesses a compact size of only 15 mm <inline-formula> <tex-math notation="LaTeX">$\times10$ </tex-math></inline-formula> mm <inline-formula> <tex-math notation="LaTeX">$\times1$ </tex-math></inline-formula> mm. A virtual impactor has been integrated as a particle size selector and the design is optimized by simulation-assisted analysis. The sensor is realized by silicon microfabrication and wafer-level packaging. Testing results show that a high measurement accuracy of <inline-formula> <tex-math notation="LaTeX">$2.55~\mu \text{g}/\text{m}^{3}$ </tex-math></inline-formula> has been achieved.