Which of the following is a recognized clean air practice in housekeeping?

Using High Efficiency Particle Air (HEPA) filters is considered a recognized clean air practice in housekeeping because HEPA filters are designed to trap a significant amount of very small particles that other vacuum cleaners might miss. These filters are capable of capturing 99.97% of particles that are 0.3 microns in size or larger, including dust, pollen, mold spores, and even some bacteria. This ability to filter out allergens and pollutants contributes greatly to maintaining indoor air quality, making HEPA filtration particularly valuable in environments where air quality is a priority, such as hotels and healthcare facilities.

In contrast, using scented air fresheners does not actually improve air quality and can even introduce additional pollutants into the air. Chemical-based cleaners can also pose risks to air quality due to the volatile organic compounds (VOCs) they may release. Traditional vacuum cleaners, unless equipped with HEPA filters, may not effectively trap allergens, allowing dust and other particles to be recirculated back into the air. Thus, utilizing HEPA filters is the most effective clean air practice among the options provided.