Pictured above is an advertisement for the Air-Maze air intake filter and flame arrester for the Model A Ford with Zenith carburetor. This ad is from the February 1930 issue of Ford Dealer & Service Field magazine.
The Air-Maze was a simple filter canister containing a fine mesh screen, but no paper element or oil bath.
The primary function of the device is actually as a flame and spark arrester. It's usefulness as an air 'filter' is probably more suited to small animals and insects, rather than fine dust particles.
The Model A was never originally supplied with a filter by Ford, leaving several aftermarket companies such as Air-Maze to satisfy the market.
In 1932, the Model B Zenith carburetor was supplied by Ford with a factory installed air cleaner and intake silencer made by Burgess Battery Company.
Ford also offered a factory heavy duty oil bath air cleaner for 1933 and 1934 trucks with the Model B Zenith carburetor.