Dongwha

Mobile research container used to monitor formaldehyde in the ambient air at six locations around the Dongwha Patinna MDF plant near Mataura, New Zealand.

Dongwha Patinna NZ Limited is a wood processing company that uses pine trees to manufacture Medium Density Fibreboard (MDF). The logs are chipped, broken down into individual fibres. Then a urea-formaldehyde resin is used to glue the wood fibres back together to form the various types of MDF.  During the manufacturing process, formaldehyde is released to the atmosphere, and, therefore the local Council has set requirements on ambient formaldehyde concentrations are permitted in the area surrounding the manufacturing site. 

The actual conditions in the Council's Air Discharge Permit are:

  • The discharge shall not cause the concentration of formaldehyde in ambient air beyond the boundary of the consent holder's property to exceed, for more than 0.5% of  the time in a twelve month monitoring period, 60 µg/m3 on a 30 minute averaging basis.  In addition, the maximum concentration shall not exceed 100 µg/m3 on a 30 minute averaging time. 
  • The concentration of formaldehyde in ambient air shall be monitored by the consent holder at six sites during each 12 month period.  Monitoring at each site shall occur for a minimum continuous period of one month during every 12 month period, so that: (1) The record of formaldehyde concentration at each site is continuous for 24 hours per day and seven days per week and able to show when the drier cyclone discharge plume direction is positive and within 30 degrees towards the monitoring site.  Interruptions for moving the location of equipment, calibration of the equipment, equipment maintenance or repair are permitted. (2) Sites are monitored using the Aero-laser AL4021 formaldehyde monitor collectively for a minimum of 40 weeks each year.
Inside the mobile research container: Installation of AL4021, mobile computer, and cooling box for the reagents (not visible).

Ambient formaldehyde monitoring is carried out at six neighbouring sites for a minimum of one month at each site, and a minimum of 40 weeks in total sampled during the annual period by the Aero-Laser AL4021. The AL4021 continuous formaldehyde analyzer is a German manufactured measuring instrument used to continuously measure formaldehyde levels in the ambient environment.  In order to use monitoring data relevant to the site being sampled only monitoring completed during 'wind positive' situation are reported. Wind positive situations are when the wind direction is within 30° either side of the sampling location.

Map of the six monitoring locations around the Dongwha Patinna MDF Plant.

The Aero-Laser Continuous Formaldehyde Analyser AL4021 is an IANZ (International Accreditation New Zealand) accredited analytical method (ISO/IEC 17025:2005).