BEIJING, April 16 -- Beijing's average PM 2.5 density in 2014 was more than double the official level targeted nationwide, a new report showed on Thursday.

Despite Beijing's attempts to limit air pollution, the average PM 2.5 reading stood at 85.9 micrograms per cubic meter, 1.45 times more than the national standard, according to "The 2014 Beijing Environment Report" released by the local environment watchdog.

With a diameter less than 2.5 micrometers, PM 2.5 is particulate matter that causes hazardous smog.

The report also revealed that the average densities of nitrogen dioxide and PM 10 both exceeded standards.

Emissions of sulfur dioxide and nitrogen oxide, however, fell by 9.35 percent and 9.24 percent respectively, the report said.

Beijing frequently suffers from thick smog, cutting visibility and posing health hazards. Local government measures to try to limit the problem have included restricting traffic and halting industrial production.