In July, North China's Hebei province saw its lowest monthly PM2.5 reading since such record-keeping began in 2013, its department of ecology and environment said.

The average concentration of PM2.5－airborne particulate matter 2.5 micrometers in diameter or smaller that is harmful to people's health－stood at 21 micrograms per cubic meter last month, down 40 percent year-on-year, the department said on Wednesday.

The monthly average density of PM2.5 for four consecutive months since April in Hebei reached the national second-level standard of 35 micrograms per cu m, meaning the air was in much better condition than it was years ago, when the readings could be as high as several hundred micrograms.

From January to July, the average density of PM2.5 was 41 micrograms per cu m, a reduction of 14.6 percent year-on-year, while the number of days with good air quality reached 144, an increase of seven days over the same period last year.

Hebei, which neighbors Beijing, has been troubled by bad air quality for years because of the province's long-existing heavy industries, including iron and steel production, as well as its coal-centered energy structure.

However, the situation has improved in recent years because of multiple measures taken by the provincial government to provide a better living environment for residents.

To reduce pollution, Hebei has shut down three iron and steel factories and eliminated 64 heavily polluting facilities such as furnaces and other coal-fired units.

Other measures include controlling emissions caused by coal consumption, vehicles, dust and the burning of straw and garbage.

"The better air quality is due to continuous improvement backed by unrelenting efforts," said Jiang Weining, deputy head of the department's air quality section.

Since 2013, efforts to reduce pollution have become more precise and strict, he added.

In addition to the government's efforts, meteorological conditions in July were also favorable for improving air quality, said Wang Xiaoli, director of the warning center for high pollution at Hebei's environment department.

"The past month saw frequent rains that could help clear the air and disperse pollutants," Wang said.

Wang Taotao, a 33-year-old mother living in Shijiazhuang, Hebei's provincial capital, said the air quality's improvement is a great benefit for residents and could boost her family's health.

"I hope my girl can see the blue sky and smell clean air every day," said Wang, who has a 2-year-old daughter. She added heavy smog that used to occur frequently during winters several years ago was very harmful, and she didn't want her child to experience it.

Other regions in North China have followed similar paths under the nation's policy to improve the environment.

Beijing also reported its lowest monthly reading for PM2.5 since 2013.

The capital's average concentration of PM2.5 in July reached 16 micrograms per cu m, according to the capital's ecology and environment bureau. The city also reported record low levels of other major pollutants, such as sulfur dioxide, PM10 and nitrogen dioxide.