Proper cabin air filter maintenance is important for many reasons. Cab air filters are probably one of the tractor components that are stretched as far as (or farther than) possible at times. While it is common practice to blow out your air filter periodically, there is a time when that is no longer going to be an adequate measure and you will have to replace it. There are several reasons why it is in both your own personal best interests and those of your tractor to do this.
It is wise to at least check your cabin air filter after every eight or so hours of operation, or more often if you are working in a lot of dust and dirt. Some filters will not need to be cleaned or changed for quite some time while others will need frequent attention. To determine if your filter needs to be replaced, hold it up to the sky or another available light source. If dim light or no light at all filters through it, it is definitely time to replace it. If you can still see light, then it may still have some life left to give. You can opt to blow it out with an air compressor to make it last a little longer, but try to avoid pushing your luck too far. Excessive use of an air compressor on your air filter will enlarge and warp the holes in it in addition to creating tears. This equates to making the filter less effective in that the enlarged holes will allow more particles to pass through, which could ultimately pose a health risk to you.
Enclosed tractor cabs are a dusty environment to begin with and can grow increasingly more so depending on your work environment. Outside air is drawn into your HVAC from the rear of your tractor, thus that air is already laden with dust, debris, and chemical agents before it enters the cabin. If your filter is dirty and thus not working, you will be inhaling the dirt and chemicals the filter should help alleviate. Breathing such particles for extended periods can result in headaches, burning throat, nausea, dizziness, and itchy, watery eyes which will jeopardize your operating abilities as these conditions could cause you to have an accident.
In order to remain safe while working and prevent overall illness, be diligent about cabin air filter replacement. When you consider that you could be inhaling fertilizer, manure, and pesticide particles along with dirt and debris, it makes sense to take every precaution you can to stay well. Keep in mind that any sickness will not only set you back financially with medical bills but will also set back your finances as paid work grinds to a halt. Don't let illness stop you because of something so easily avoidable. Change that filter and stay healthy in the field.