Problem in indoor air quality in cars. how to solve?

Let's start with the causes that cause poor air quality, like odors, for example. The evaporator condenses the air humidity of the passenger compartment of the vehicle, which in turn is drained out through a drain installed in the lower tray of the air box, but in the case of blockage of this drain by leaf of trees that penetrate into the box by Air inlet (air renewal), it may cause a build up of water. Well, what happens then when you use the air conditioner on a hot day and then stop using it for a long time? The water that was deposited in the tray "rotting" as a kind of mud, creating fungi and bacteria that provoke bad smell when the air conditioning is turned on, in some cases cause sneezing in some more sensitive people. What can be done in these cases? The user should opt for preventive maintenance in the automotive air conditioning system, for example, take advantage of the winter season to clean the air box, apply products such as bactericides, anti fungi, exchange the anti-pollen fliter, in the latter , The manufacturer indicates that the exchange should be made every 15,000km or 01 year (whichever comes first). Some service providers have adapted these filters on vehicles that do not have this item, which results in improved indoor air quality.