City Employee of an Auto Emission Inspection Station in Downtown Cincinnati, Ohio, Holds a Probe Attached to the Tailpipe of a Car. the Probe Is Held in the Car Exhaust for 8 - 12 Seconds While Gases Pass to the Analyzer Which Reads the Amount of Carbon Monoxide and Hydrocarbon Emissions.
All Light Duty, Spark Ignition Powered Motor Vehicles in the City Must Be Tested for Exhaust Emissions. All Vehicles Registered in the City Must Undergo Annual Safety Checks 08/1975. Photographer: Eiler, Lyntha Scott. Original public domain image from Flickr