Shanghai's indoor concentration of PM2.5 pollutants has declined following the city's ban on smoking indoors and in certain public areas, according to a study released by Fudan University's Health Communication Institute.

A team of researchers took air samples from various public places — such as office buildings, hotels, restaurants, pubs, karaoke outlets, entertainment venues and farmers' markets — across the city before and three months after the ban on smoking was enacted.

The researchers found that the indoor concentration of PM2.5 pollutants had fallen to 64 micrograms per cubic meter (µg/m3), from 115µg/m3.