An air filter for use in filtering air entering an operator's cab of a human-operated machine. A fine mesh screen and air permeable fibrous cover are added to the air outlet side of a conventional air filter. An accordion-shaped filter element of the conventional filter is located upstream of the fine mesh screen. Granular filter material such as activated charcoal fills the space between the accordion-shaped filter element and the fibrous cover. An air-impermeable strip may be added at the top portion of the fine-mesh screen across the full width of the air filter to prevent air from flowing through a void in the granular filter material which may develop over time due to settling.
