Answer: The general misunderstanding is that it is believed that selecting a single filter with the corresponding processing accuracy according to the required air quality can meet the requirements and save costs. In fact, although the required air quality is determined by the processing accuracy of the selected single filter, without the pre-treatment protection of the lower-level filter, the high-precision filter element will soon be blocked due to excessive load, which will speed up the replacement frequency of the filter element, thereby increasing production costs in disguise.