City's indoor concentration of PM2.5 pollutants declines following smoking ban

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. 

PM2.5 refers to airborne particles smaller than 2.5 micrometers in diameter. 

They are able to travel deeply into the human respiratory tract, reaching the lungs. Exposure to fine particles can cause short-term health effects such as eye, nose, throat and lung irritation, coughing, sneezing, runny nose and shortness of breath. Studies suggest that long-term exposure to fine particulate matter may be associated with increased rates of chronic bronchitis, reduced lung function and increased mortality from lung cancer and heart disease.  

Despite concerns that the smoking ban may spur more men to smoke in restrooms, the researchers found that the concentration of PM2.5 in men's restrooms declined to 115 µg/m3, from 170 µg/m3.

At restaurants, the percentage of smokers fell to 11 percent, from 39 percent.

According to data collected from air-quality monitors installed in 22 restaurants in three districts, the density of nicotine declined to 0.63µg/m3, from 1.18µg/m3, while the density of nicotine in restaurant toilets dropped to 1.59µg/m3, from 3.97µg/m3.

About 90 percent of the public places that the researchers surveyed displayed no-smoking signs, and 40 percent of them had initiatives to curb smoking. 

In April, the first month after the ban on smoking took effect, the 12345 hotline received 6,937 complaints about breaches of the ban, said the Shanghai Health Promotion Committee. The number of complaints declined to 3,254 in May, and to 1,993 in November. 

A phone survey conducted by Shanghai Statistics Bureau found that 70 percent of respondents said the ban was working well in reducing smoking, and 80 percent of respondents said they were willing to participate in programs to quit control. More than 70 percent of respondents who smoked said they had been curbing their habit or quit smoking following the ban.

In March, Shanghai introduced its toughest ban on smoking by prohibiting smoking in all indoor areas and certain public places such as children's hospitals, sports venues, cultural relic protection sites, and bus stops.