Beijing has met a national standard for the first time that sets a safe level for one type of harmful air pollutant, according to the city’s environmental protection bureau. The levels of PM2.5 – small particles in the air deemed particularly harmful to health – averaged 34 micrograms per cubic metre last month, the bureau said on Wednesday. The national standard is below 35 micrograms, it said. The benchmark was first set by the authorities in 2012. Twenty-five of the 31 days in January also saw “good” or “excellent” air quality, according to the Beijing Municipal Environmental Protection Bureau. How did Beijing become one of China’s top cities for air quality? The reduction in PM2.5 levels amounted to a 70.7 per cent cut compared with the same month last year. The improvements mean the capital’s average air quality ranks eighth among all cities in China. Beijing entered the top 10 rankings for the first time in December. Other major pollutants also saw significant falls in Beijing last month, according to the bureau. Levels of sulphur dioxide, nitrogen dioxide and PM10 particulates each fell by 55.6 per cent, 35.4 per cent and 51.1 per compared with January last year. Dry and windy weather this winter has helped disperse air pollution in Beijing, the bureau said, and the good air quality is forecast to last for another week. Beijing’s air pollution has become notorious in recent years, particularly in winter when coal-burning central heating systems are ramped up. Pictures of the capital’s buildings shrouded by heavy smog have regularly made headlines around the world. From coal to cars: Beijing moves up a gear in the war against air pollution China’s government said it was declaring war on pollution in 2013 and efforts to curb smog include closing down or moving heavily polluting factories and restrictions on the use of cars. This winter the measures were further tightened and the government has tried to introduce more cleaning-burning natural gas to replace coal-fuelled boilers.