Every day in August had good air quality in Heilongjiang province, with the average concentration of PM2.5 — particles that are 2.5 micrometers in diameter or smaller and are harmful to health — dropping year-on-year from 12 micrograms per cubic meter of air to 9, according to the provincial department of ecology and environment.

August also had the best measurements since the province began air quality monitoring, the department said.

In the first eight months of this year, Heilongjiang saw continuous improvement of its air quality, with the proportion of good days in city-level areas reaching 95.2 percent, up 2 percent year-on-year.

The proportion of days with good air quality across the province reached 66.4 percent, with a year-on-year increase of 12.6 percent.

In the first eight months, the average concentration of PM2.5 matter in the province was 24 micrograms per cubic meter, a decrease of 3 micrograms, which can meet the second-level national air quality standard.

Because of its policies — such as the adjustment of industry, energy, transportation and land use, and a ban on burning straw — the province has seen the continuous improvement of air quality in recent years, the department said.

The province also launched a series of measures related to weather that it said help solve seasonal air quality problems.