Environment Canterbury has ramped up its campaign to clean up smoky chimneys.

Environment Canterbury's campaign to eradicate smoking chimneys from Christchurch's clean air zones is no longer on a slow burn.

Air pollution officers tasked with identifying woodburners that produce smoke for more than 15 minutes after ignition started patrolling on Monday.

By Wednesday nine warning notices had been issued - the initial phase of a process that culminates in a $750 fine.

Lower Cashmere and St Albans - suburbs where air pollution is prevalent - were the first areas targeted; ECan's six 'smoke spotters' extend their search citywide soon while Timaru comes under scrutiny in a fortnight.

The houses already pinpointed received instructions on how to set a fire properly and they will be issued a formal warning if there is no improvement in their burning practices.

"They (spotters) go back and check a few days later to give them time to change the way they are burning," said ECan spokeswoman Nadeine Dommisse.

If smoke is still visible after the second warning, an abatement notice is issued - if that is breached the user is fined. They are able to appeal.

The introduction of spotters, who also rely on a pre-existing database and anonymous tip-offs, follows ECan's month-long attempt to educate people who use woodburners.

Letters were sent to all households with woodburners with tips on how to operate a smoke-free fire.

Dommisse said ECan's www.letscleartheair.co.nz website had received 17,000 hits since June 3, while the smoke-free burning video had been viewed 4500 times.

About 20 people had requested in-home training while another 40 had requested financial assistance through Community Energy Action to help improve their heating.

The 'no visible smoke rule' - which also applies to properties less than 2 hectares outside a clean air zone - is the focal point of ECan's proposed Canterbury Regional Air Plan.

ECan said although woodburner users believed they were already smoke-free, a study of urban chimneys indicated that improvements had to be made, even where modern units had been installed.

Commissioner David Bedford admitted it would be difficult to enforce the rule.

"Three or four people patrolling the streets of Christchurch aren't going to catch everybody," he said, adding: "The key is education, which changes behaviour. The enforcement happens for the small number that just don't care."

"We have enforcement people, and we have home heating officers. They're out there if somebody needs some help."

According to ECan statistics there were 19 high pollution days in Christchurch in 2014, Timaru topped the statistics with 41, while excessive readings were also recorded in Kaiapoi (14), Ashburton (9), Waimate (8), Geraldine (4) and Rangiora (3).

So far this winter Timaru again leads the way with 13, followed by Kaiapoi (10), Waimate (7), Christchurch (5), Rangiora and Geraldine (2) and Ashburton (10).