When it comes to air filters, size does matter. A higher MERV rating is beneficial, but if your system only fits a 1- or 2-inch filter, a high MERV rating could be detrimental. A 1-inch filter with less surface space will clog up quickly and need to be replaced more often than a coarser filter. The combination of a thin air filter with a high MERV rate can also restrict airflow and cause excessive wear and tear.
The best thing to do is to upgrade to a 2-inch filter or even a 4-inch filter. Most return air cleaner grilles accept a 2-inch filter instead of a 1-inch filter. Filters only work if air has to pass through them, so leaving a gap of 1 inch will cause an disproportionate amount of air to flow through the hole, worsening the situation. For the same length and width, you can get 1 inch, 2 inch, 4 inch, and even thicker filters.
A comparison between the 1 and 4 inch oven filter reveals that the 1-inch filter may need to be changed every month, while a 4-inch air filter can last up to six months. The thickness of the filter determines the surface area, so the 1-inch filter may be too shallow, causing a loose fit that allows unfiltered air to enter the ductwork. If it's choosing a smaller filter or nothing at all, at least do something like taping or taping a piece of cardboard filler to the filter to get the right size. Whatever you do, don't use two filters as this will further restrict airflow and could damage the system.
In conclusion, if it fits your oven and your duct system is in good condition, then a 4-inch air cleaner is better than a 1-inch air cleaner when it comes to improving air quality. It is worth investing in a more expensive filter as it will provide better filtration and last longer.