Mosgiel is heading for one of its worst air pollution winters since recording began in 2006.
The town equalled its highest-ever air pollution reading with 108mcg on June 24.
And has so far this year it recorded seven readings higher than the national environmental standard of 50mcg per day.
Air-quality readings are taken by a continuous monitor in the Factory Rd industrial estate.
Otago Regional Council air quality scientist Deborah Mills said the average number of high readings for Mosgiel was seven and the town had equalled that.
''It's a little concerning given we are only halfway through winter.''
The exceptionally high reading of 108mcg was preceded by a 54mcg day and also coincided with a period of very cold weather with temperatures getting down to -3degC and -2degC on those nights with no wind.
''It's a classic high pollution situation.''
While the council had not received any complaints about the air quality that day, the levels of air pollution were high all day and it had heard there were two large outdoor burn-offs at the south and north of the Taieri Plain which could have contributed, she said.
''It just does not disperse on those days.''
The high readings contrasted with last winter when there were only five high readings recorded, with the worst 62mcg.
The largest number of high readings recorded was in 2008 with nine and the year with the lowest was 2007 with only four high readings.
''We're going to keep an eye on Mosgiel and do an analysis at the end of winter.''
The town was in airzone two and had until 2016 to meet the national PM10 (very small particles) standard of having no more than three 24-hour readings exceeding 50mcg, per year.
Council engineering, natural hazards and science director Gavin Palmer said it was difficult to see a trend in the data with such a short record and with so many variables.
The council had only been recording air quality in Mosgiel since 2006.
''We need a longer record to judge,'' Mr Palmer said.
''Clearly we would like to see less exceedences.''
Council environmental monitoring and operations director Jeff Donaldson said there had only been one domestic chimney complaint this winter in Mosgiel and one outdoor fire complaint.
