Other Pollutants

Carbon monoxide (CO) 

In Canterbury towns CO mainly comes from motor vehicle emissions and, in winter, from home heating fires. The Ministry for the Environment has set the following guidelines:

• 10mg of CO per cubic metre of air averaged over 8 hours. 
• 30mg of CO per cubic metre of air averaged over 1 hour

Both guidelines apply now. The National Environmental Standard (NES) says the 8 hour guideline should not be exceeded more than once a year.

Where Do We Monitor Carbon Monoxide?

Monitoring of CO is carried out continuously in Christchurch (St Albans, Woolston, Riccarton Rd, Burnside), Timaru and Kaiapoi, where the CO emissions are highest.  In other towns Environment Canterbury has monitored CO on a rotational basis.

Carbon Monoxide Concentrations in Canterbury

The highest concentrations occur during the winter months, usually in June or July.  During winter weather conditions like the lack of wind, prevent the CO from being blown away and allow the concentrations to build up overnight.

More Information

You can find more on carbon monoxide concentrations measured in Canterbury in the annual air quality monitoring reports. 
 
The Ministry for the Environment has more information on carbon monoxide. 

Nitrogen dioxide (NO2)

In Canterbury towns NO2 mainly comes from industry, motor vehicle emissions and in winter, from home heating fires. The Ministry for the Environment has set the following guidelines:

• 200 ug of NO2 per cubic metre of air averaged over one hour 
• 100 ug of NO2 per cubic metre of air averaged over 24 hours

Both guidelines apply now. The National Environmental Standard (NES) says the one hour guideline should not be exceeded more than nine times a year. 

Where do we Monitor Nitrogen Dioxide?

Monitoring of NO2 is carried out continuously in Christchurch.

Nitrogen Dioxide Concentrations in Canterbury

The highest concentrations occur during the winter months, usually in June or July, when weather conditions like the lack of wind, prevent the NO from being blown away and allow the concentrations to build up overnight.

There have been any exceedences of these guidelines in recent years.

More Information

You can find more data on nitrogen dioxide concentrations measured in Canterbury in the annual air quality monitoring reports. 
 
The Ministry for the Environment has more information on nitrogen dioxide.   

Sulphur dioxide (SO2)

In Canterbury towns SO2 mainly comes from industry , motor vehicle emissions, and, in winter, from home heating fires.

The Ministry for the Environment has set the following guidelines:

• 350 ug of SO2 per cubic metre of air averaged over one hour 
• 120 ug of SO2 per cubic metre of air averaged over 24 hours

Both guidelines apply now. The National Environmental Standard (NES) says the one hour guideline should not be exceeded more than nine times a year.

Where do we monitor sulphur dioxide?

Monitoring of SO2 is carried out continuously in Christchurch, Timaru and Kaiapoi. In other towns Environment Canterbury has monitored SO2 on a rotational basis.

Sulphur dioxide concentrations in Canterbury

Where the main source is home heating fires or vehicles, the highest concentrations occur during the winter months, usually in June or July.  During winter when weather conditions like the lack of wind, prevent the NO from being blown away and allow the concentrations to build up overnight Where the main source is industry a seasonal variation is not so evident.

Both the 24 hour and 1 hour average guidelines have been exceeded in Christchurch at the Hornby and Woolston monitoring sites which are in industrial areas, though the NES has not been breached. In other towns the highest concentrations are lower than these guidelines.

More Information

You can find more data on sulphur dioxide concentrations measured in Canterbury in the annual air quality monitoring reports. 

The Ministry for the Environment has more information on sulphur dioxide.  

Hazardous air pollutants (HAPs)

In Canterbury most hazardous air pollutants come from industry. However the main source of benzene (one of the HAPs) is from motor vehicles.  The Ministry for the Environment has set guideline values for 8 priority HAPs. Environment Canterbury has monitors the following hazardous air pollutants: poly-aromatic hydrocarbons (PAH), volatile organic compounds (VOC) and organochlorines. These are terms for groups of pollutants with a similar type of chemical structure. Often one pollutant is used as an indicator of the group. The following guidelines have been set for benzo(a)pyrene and benzene:

• 0.3 ng of benzo(a)pyrene per cubic metre of air averaged over a year
• 10 ug of benzene per cubic metre of air averaged over a year

The guidelines apply now.

Where do we Monitor Hazardous Air Pollutants?

PAH monitoring was carried out in Christchurch during winter 1999 and from July 2002 to June 2003. Monitoring involved collecting a sample for 24 hours. During 2002/2003 this was carried out every sixth day for one year. The samples were analysed by a laboratory and concentrations for 16 PAHs were reported. The concentrations of benzo(a)pyrene, one of the PAHs reported, were averaged. 

VOCs (benzene, toluene, ethyl benzene, xylene and BTEX) monitoring has been carried out at a number of locations around Christchurch in 1996/7, 2001/2 and 2003/4.in 1996/7, 2001/2 and 2003/4. A study is currently underway, due to be completed in autumn 2009. This study also includes monitoring in Timaru.

Hazardous Air Pollutants Concentrations in Canterbury

The guideline for the average benzo(a)pyrene (one of the PAHs) concentration has been breached.Benzene (one of the VOCs) concentrations measured in 2003/4 were below the current guideline. HAPs were not measured outside Christchurch.

More Information

You can find the full data on hazardous air pollutants emissions in the annual air quality monitoring reports.  
 
The Ministry for the Environment has more information on HAPs. 

Ozone (O3)

Ozone comes from a chemical reaction between motor vehicle emissions (NOx and VOC) which occurs in strong sunlight and light winds. The Ministry for the Environment has set the following guidelines:

• 150 ug of O3 per cubic metre of air averaged over one hour 
• 100 ug of O3 per cubic metre of air averaged over 8 hours

Both guidelines apply now. The National Environmental Standard (NES) says the one hour guideline should not be exceeded.

Where Do We Monitor Ozone?

Highest concentrations can occur downwind of a city like Christchurch. For this reason ozone has been measured in Kainga (Christchurch North) and in Lincoln.

Ozone Concentrations in Canterbury

Ozone has been monitored during the summer of 1998 and 2003. Guideline values were not breached.

More information

You can find more data on ozone concentrations measured in Canterbury in the annual air quality monitoring reports. 
 
The Ministry for the Environment has more information on ozone