The council said in a statement yesterday that was 16 more breaches than last year.
However, it said climatic and geographic factors were at play.
Council air quality scientist Sarah Harrison said "extreme seasonal patterns" — where winter air quality was particularly poor compared to summer — indicated home heating, such as fireplaces, was the major source of pollutants in the air.
But breaches also varied from year-to-year, which indicated climate cycles, such as El Nino and La Nina, played a factor too, Ms Harrison said.
Winters were worse not just when they were cold and people burned wood or coal to stay warm, but also when low temperatures combined with lower wind speeds, she said.
Calm conditions created more opportunities for pollution to build up.
"We also see more instances of natural inversion layers throughout winter, where the weather can act like a blanket, trapping pollution close to the ground. Normally, warm air rises and takes pollution with it, but in winter, cold air gets stuck under the warmer air, holding the pollution near where people breathe."
Yesterday’s statement from the council urged Otago residents to help the region’s winter air quality by replacing older wood burners and fires with ultra-low emission burners, pellet burners or heat pumps".
— APL