Abstract: An air quality sensor system is disclosed comprising a housing defining a sidewall means. An air input is located on a first sidewall of the sidewall means with an air output located on a second sidewall of the sidewall means angularly disposed relative to the first sidewall of the sidewall means. A particle sensor including a fan is located within the housing and interposed between the air input and the output for sensing the number of particles passing between the air input and the air output. Preferably, a temperature and humidity sensor, a volatile organic compound (VOC) sensor and a carbon dioxide (CO2) sensor are provided for sensing the ambient air. A transmitter may be included for transmitting data from the particle sensor.