WASHINGTON (DC News Now) — If you’re concerned about poor air quality, the EPA has a simple method to help filter the air that’s in your home or making its way into it.

Portable air filters, which can be purchased online, typically use a high-efficiency particulate air (HEPA) filter to clean the air in your home. The EPA recommends making one at home if you cannot easily or affordably obtain one.

You can do it by attaching a furnace filter to a box fan using tape, brackets, or a bungee cord.

Another method is to form a triangle using two filters and some tape.

To ensure your DIY filter works well, be sure to check its Minimum Efficiency Reporting Value (MERV). It should be no less than a 13, and you should find information about it in the manual. Align the arrows on the filter with the direction of the airflow, and make sure to form a strong seal between the fan and the filter.

The filter will need to be changed regularly for continued use; however, the EPA does not recommend routine use of DIY filters, as there is limited data available on their efficacy.

Do not leave it unattended, and do not use it while sleeping.