In view of the fact that air pollution is a widespread and ongoing problem, it is recommended to leave your air purifier on all day. This is as safe as leaving the microwave, refrigerator, television or air conditioner on all day. Moreover, if you're using a HEPA or PCO air purifier in your room while you sleep, you can rest assured that it won't be bad for your health. It will also help you sleep more comfortably from the perspective of breathing.
Some purifier companies suggest running your air purifier all day long. But is it really necessary? If so, isn't it a big waste of filters and energy to run the purifier all the time? Good HEPA filters come with activated carbon filters that allow them to eliminate odors by absorbing air particles and gases that cause odor. By running your home air purifier all the time, you can keep the air in your home clean and prevent new pollutants from building up. Therefore, considering the cost, it is not recommended to leave an air purifier on all day or to run the air purifier 24 hours a day.
However, you can run your air purifier at low or medium while you're away to make sure it always works. For more information on what exact air purifiers you can get that can work all day and year round, see my post on recommended room air purifiers here. Almost all air purifiers have an ACH rating, but the ACH provided by air purifiers is not the same as the ACH provided by outdoor air ventilation. If you want to learn more about cleaning your home for fresh air, you can check out my full post on that here.
If you need an ionic air purifier for any reason, get it in combination with a HEPA or PCO air purifier with the option to turn the ionic part on and off. Even better, there are now purifiers on the market that you can link to your WiFi and control from your phone or laptop. On the one hand, a purifier works with indoor air, so pollutants from the outside air do not enter the house like ventilation. On the other hand, opening windows to ventilate the house is not enough to keep indoor air clean and healthy.
That's why it's best to leave your air purifier turned on all day. In addition to using an air purifier all day, the house's energy consumption will inevitably increase and the electricity bill will be huge. In conclusion, if you want to ensure that the air in your home is always clean and healthy, it's best to keep your air purifier turned on all day.