Ballance Agri-Nutrients has spent $8.5 million to improve air quality around its Mount Maunganui fertiliser works, including a better quality of life for the Whareroa Marae community.
The converter commissioned last year has reduced emissions to the top 5 per cent of similar plants around the world, operations manager Rob Larman said.
''We are really pleased to see the real difference that has been recorded in local air quality.''
Ballance Agri-Nutrient's clean-up was among initiatives to crack down on air-borne pollutants in the port and Mount industrial area including dust, sulphur dioxide, hydrogen sulphide and the toxic gas used to fumigate log stacks - methyl bromide.
Complaints about air quality generated from the port and Mount industrial area had soared over the past six years, from 23 in 2012 to 283 in 2017.
Reece Irving, a member of the regional council's pollution compliance team, updated the city council's environment committee recently on progress to improve controls on the discharge of pollutants able to be inhaled.
''Residents at Whareroa Marae and surrounding community have been affected by discharges from nearby industrial sites,'' he said.
However, they were a lot happier since the Ballance capital works upgrade took place, Irving said.
And the port company had responded by employing its first environmental co-ordinator, Joey McKenzie.
The regional council was spending $500,000 to install four new air monitoring stations inside the port, targeting methyl bromide. Genera Ltd was the only consented user of methyl bromide on the wharves.
Irving's report also detailed how five other air monitoring sites in and around the Mount side of the port were testing for sulphur dioxide, dust particles of all sizes, and particles that were 10 micrometres in diameter or smaller. A human hair was about 70 micrometres.
He said the port was ''host to a multitude of dust emitting activities'' and very fine particles could have severe human health effects.
According to the US Environmental Protection Agency these tiny particles posed the greatest health problems because they could get deep into lungs and may even enter the bloodstream.
The existing monitoring station on Whareroa Marae behind the fertiliser works was also testing for hydrogen sulphide and hydrogen fluoride. Sulphur dioxide was the main complaint from the marae.
Irving said sulphur dioxide and hydrogen sulphide had a distinctive rotten egg odour and taste and were the by-products of industrial processes such as fertiliser manufacture, fuel refining and burning diesel and fuel oils.
He said shipping was likely to be the biggest emitter of particles but the council had no authority under the Resources Management Act to control these emissions.
Auckland was going to mains power electricity to run ships in port so they did not have to run their engines using heavy fuel oil. Another alternative was lighter fuel-burning generators.
Irving disclosed they would be considering aircraft movements at Tauranga Airport when they looked at all sources of discharges.
One of the key sources of dust emissions was palm kernels and other forms of stock food during the unloading of bulk cargo ships. A lot of dust was also created by log handling, the transportation of goods on uncovered or poorly covered trucks, and from unsealed areas.
''There is still a lot of unsealed yards in the Mount industrial area.''
He said odour was by far the biggest cause of complaints, with almost all the 227 smell complaints last year sourced from a pet food factory.
''It caused neighbours a lot of grief.''
Ballance was one of three businesses in close proximity to each other discharging gases with rotten egg odours. Sulphur dioxide had not exceeded permitted levels from Ballance while Waste Management's new consent was expected to have far greater controls over hydrogen sulphide.
Irving said the primary focus of four additional council staff would be dust discharges. The council was becoming more proactive with big business and had established the Mount Industrial Environmental Group. Air discharge reduction plans were being developed with major players in the Mount industrial area.
He said they would be going to all industrial premises to give them time to come up with solutions. If not, they would have to get consents.
The port had become a lot more proactive about achieving positive environmental outcomes over the past year to 18 months, Irving said.
Air quality complaints in the port and Mount Maunganui industrial area
2012: 23 (odour 11, dust 6, smoke 6)
2014: 65 (odour 25, dust 35, smoke 2, other 3)
2016: 105 (odour 82, other 10, dust 7, smoke 6)
2017: 283 (odour 227, dust 20, other 20, smoke 16)