Here are a couple relevant threads that could be helpful:
As most of us have seen, there are various sources to buy a plastic grid to keep the HVAC air inlet under the hood clear of debris. I now also saw another type of product surface. An actual filter that fits over the air inlet, and can be combined with the plastic grid on top, I didn't see it...
teslamotorsclub.com
When you change the cabin filter in cars they are usually full of leaves, bugs, and all kinds of particles. Looking at the intake under the frunk I thought it would be easy and cheap to add some pre-filtration there. Went to the hardware store and purchased a sheet of "cut to size" universal...
teslamotorsclub.com
To summarize... debris (leaves, needles, etc.) do get into the outside air intake and can lead to bad smells in the cabin when they decompose inside the car. And it’s very difficult to clean out that debris once it’s gotten in. So adding SOMEthing to keep that debris out is highly encouraged.
Then the question is, what to use? There are 3 main options:
1. Custom-fit plastic covers with small holes in them to let air through while keeping out leaves. But smaller debris like pine needles or stems or leaf fragments can still possibly get through. (Available on Amazon and elsewhere online.)
2. Aftermarket intake air filters made with finely-woven filter material — the kind of material that is typical in car and furnace filters and would filter out even very tiny dust particles. But at least one forum member reported that this type of filter added too much flow restriction and significantly reduced airflow from the cabin vents. (Available on Amazon and elsewhere online.)
3. A fibrous, high-flow, cut-to-size furnace filter that can be bought for cheap ($5-$10) at Walmart or Home Dept and cut with scissors to fit the shape of the intake opening. This seems to be the most effective option. It catches leaves and smaller needles, is moisture resistant, and it doesn’t restrict airflow much at all.
Here are a couple of these to choose from:
Budget Washable Air Filter FPR 2 Air Filter is designed to help reduce dirt buildup in air ducts, air conditioners and furnace systems. This product can be washed and reused. Filter can be modified and
www.homedepot.com