In addition to formaldehyde products used by ice insects are nano titanium dioxide photocatalyst developed by Zhejiang University. Natural light is needed to react. If this technology is used indoors, the effect may be greatly reduced, and it is self-testing. The price is still expensive.

In governance, we must sign an effective treaty. When we find a third-party CMA agency for testing, how can we compensate if the results are not up to standard? We need to support multi-phase effects, testing after one month and testing after three months.