Heavy smog that has already devastated northern China regions, including Beijing and its surrounding provinces, for days is expected to continue into the upcoming National Day holiday, the official meteorological service warned on Monday. Unfavourable weather conditions are hindering the dispersal of air pollutants and prolonging the smog, said weathertv.cn, an internet outlet responsible for publishing official meteorological information, a day before the country kicks off its major holiday of the year. Most regions of northern China are at the level four weather condition level while some regions have reached level five, the website noted. Weather conditions levels refer to a standard that describes how the overall weather condition in an area affects the dispersal of air pollutants, with level one best for dispersing air pollutants and level six the worst. As of noon on Monday, the Beijing environmental monitoring centre put the air quality index that measures the amount of tiny particles which critically damage health, PM2.5, at 225 micrograms per cubic metre. The US embassy’s readings put the number at around 200 and described the situation as “very unhealthy”. Video: dangerous levels of smog shrouds Beijing and Huainan Smog will cover Beijing, Tianjin, large parts of Hebei province, and partial regions in Shanxi, Shandong, and Shaanxi provinces on Monday, said a forecast on the website. It advised the public to wear a mouth-muffler outdoors and to avoid intense exercise. Heavy smog, which mostly happens in the north of China in winter, can damage people’s health and causes higher rates of cancers and heart diseases. One study in June concluded overexposure to such weather condition could cut the average life expectancy by up to five years. Heavy air pollution has also increasingly fuelled public criticism of the government for not responding effectively to the air pollution problem. Responding to public reaction, the Beijing government on its microblog account cited a January news report to reassure the public that the city’s air quality has steadily improved over the past 14 years. However, online comments under the post showed that many were unconvinced by its claim as they recalled northern cities of China had experienced the worst smog in years in January with some reports saying that smog level readings had broken records. Some users even quipped that the government’s post was a rumour, referring to a ongoing high-profile government campaign to rein in online rumours. “Beijing government blog is spreading rumours,” said an online user with the certified identity of a senior reporter at the magazine Times Figure .