The move is considered a big improvement in air quality monitoring and it will be available on an official website.
Information on particulate matter in China used to be limited to PM10, or particulate matter 10 microns or less in diameter.
There has been public demand in recent years for data on PM2.5, a gauge that monitors fine particulate matter with a diameter of 2.5 microns or less.
It is considered to be more hazardous to people's health.
A total of 496 monitoring sites have been set up in the 74 cities, state-run Xinhua new agency.
According to experts, China has replaced the US as the world's biggest emitter of greenhouse gases with a CO2 emission of 9.7 billion tonnes.
