But all of that are usually discommodious and insecure to some extent, for example toting, forgetting, losing and peculating and so on.

但各都或多或少地伴随着要携带、易遗忘、易丢失、被盗用等不方便不安全的因素。

Weighing filtration membrane is often used to get the dust concentration of environment.However,this method is discommodious and can not get the instantaneous transformation of dust concentration.

环境粉尘浓度的定一般使用滤膜称重方法,方法费时费力,且不能到瞬时粉尘浓度的变化。