Sydneysiders experienced 81 days of hazardous, very poor or poor air quality last year, more than the combined total for the previous 10 years, and health experts say new policies are needed for this unprecedented length of exposure to bushfire smoke.

Of those 81 days, 28 were classified as hazardous, the worst-possible level, another 21 were very poor and 32 were poor at one or more monitoring station in Sydney.

Last year was the first time since at least 2009 that the city has had more than 18 days in a calendar year when the air quality reached poor, very poor or hazardous levels, a Herald analysis of NSW Department of Planning, Industry and Environment data shows.

There have already been 14 such days this year.