Indoor air quality testing equipment analyzes interior air and provides measurements for various factors that affect indoor air quality. Combustible gas detectors and kits detect and measure the amount of combustible gases in the air. Combustible gas detector accessories enhance, modify, or repair gas detectors. Particle counters measure the size and relative amount of airborne particles within specific size ranges. Particle counter accessories help users operate and maintain their particle counters. Gas analyzers detect and measure the relative amount of specific gases in the air. Gas analyzer accessories help users operate and maintain their gas analyzers. Indoor air quality testers analyze interior air for factors that negatively impact air quality. Indoor air quality sampling pump accessories help users operate and maintain sampling pumps. Gas detectors for smartphones connect to compatible devices and measure the amount of specific gases in the air.