Air
Our air quality is fantastic and is the envy of the world but sometimes it 'bombs out'
Air
Our air quality is fantastic. Mostly it is healthy, invigorating and the envy of the world. Sometimes, and in some circumstances, it 'bombs out' and it is hard to understand why we haven't fixed it.
More than 90 percent of our country has clean air nearly all of the time, and its quality is stunningly good. It is good in the sense that, in most places, most of the year the air is fresh and suffers little from air pollution. The term 'air pollution' includes anything in the air that we don't want, usually because it affects our health or the environment we live in.
Sulphur dioxide
Sulphur dioxide is the pollutant gas that can make acid rain. It can sting and cause breathing difficulties. We don't have acid rain in New Zealand.
In New Zealand we have a legally binding national environmental standard for sulphur dioxide that means we will never have acid rain. And we will never have concentrations of sulphur dioxide that makes breathing difficult. Even for asthmatics.
Other pollutants and gases
Most other parts of the world have trouble with carbon monoxide, nitrogen dioxide and ozone. Whilst not being perfect, we have binding standards that mean they should never become a real problem in New Zealand.
'Bombing out' - soot
Where we 'bomb out' is soot. Tiny particles you can't even see in the air that mainly come from heating our homes and our hot water with wood or coal. Some of it comes from smokey vehicles, especially in Auckland.
Our sooty air is found in about 20 or 30 towns or cities. Colder places are worst, including Timaru, Christchurch and Alexandra. The low-lying flat land of the Canterbury Plains is surrounded by hills that help trap a layer of soot over the city of Christchurch on cold days. Auckland's air quality is also affected by winter home heating but traffic pollution is a bigger contributor in this area.
Home fires
We really like our open fires. Thirty-eight percent of our homes use wood burners. Forty percent of domestic wood burners are more than 10 years old, and only one in four have been installed in the past five years. Older wood burners are less efficient and produce more smoke.
The trouble with soot
'Soot' is a name for fine particles of smoke. Fine soot particles are tinier than the width of a human hair, and they can be breathed into our lungs.
They cause anything from coughing and wheezing to respiratory diseases, and even premature death.
It is estimated that breathing airborne soot causes more premature death than road accidents.
Cars
Cars and trucks cause an air pollution problem in Auckland. Lots of cars with dirty exhausts, especially diesel ones often moving very slowly, is not good. Cars and trucks are a bigger proportion of Auckland's problem is summer as there is little home heating.
Airsheds
The places in New Zealand that have problems with soot have been identified as 'airsheds'. Within airsheds regional councils are required to clean up by 2013.
Fine soot in Auckland PM10 Summer Weekday (total = 10 tonnes/day)
Source: Auckland Regional Council
Text description of image
The graph shows the sources and relative values of fine soot in Auckland in summer:
- Domestic: 2 per cent
- Industrial: 23 per cent
- Cars and trucks: 75 per cent.
This graph shows that during the summer cars and trucks contribute the most to PM10.
Fine soot in Auckland PM10 Winter Weekday (total = 29 tonnes/day)
Source: Auckland Regional Council
Text description of image
The graph shows the sources and relative values of fine soot in Auckland in summer:
- Domestic: 64 per cent
- Industrial: 9 per cent
- Cars and trucks: 27 per cent.
This graph shows that during the winter on top of the contribution from cars and trucks there is additional PM10 from domestic sources, e.g. home heating.
Canterbury airsheds
Text description of image
This map shows the 7 airsheds in the Canterbury Region. They are: Rangiora; Kaiapoi; Christchurch A,B,C,D,E; Ashburton; Geraldine; Timaru; Waimate.
Brilliant again - lead
New Zealand used to have a problem with lead. Lead in paints, lead in soldered food cans, but mostly lead in the air.
Lead in the air came from vehicle exhausts because we used to add lead to petrol to improve the octane rating. This was to improve engine performance and stop engine 'knock'.
The lead in the atmosphere was bad especially for children as it affected their nerve and brain development.
Today we ban lead in petrol, and lead in the atmosphere is no longer a problem. We refine the fuel a bit more to keep the engine performance.
Combined with the removal of lead solder from food cans, by 1998 our exposure to lead had dropped by more than 95 percent. There is no longer a health risk from lead when living next to a busy road. The graph below shows lead levels at four busy Auckland sites (Penrose, Mt Albert, Mt Eden and Queen Street), between 1984 and 2002.
Annual Lead Levels in Auckland 1984-2002
See chart at full size including text description
Getting rid of pockets of poison
Until recently we had some pockets of poison in amongst our clean air. We are getting rid of them.
For example, we used to renovate our bitumen road surfaces by burning off the road surface. The smoke and poison coming from this was awful. Now we have banned that practice. We have also banned other poisonous activities like fires in landfills and burning of tyres in the open.
Some schools and hospitals had old fashioned incinerators. They produced foul fumes, including toxic dioxins, especially where plastic was burned. They are now on the way out. Unless they get special approval, they must go by October 2006. The Ministry of Education is running a "Bin it, don't burn it" campaign, and is expecting to see a big reduction in the number of schools running incinerators.
Big breaths
Fill your lungs and feel good about it. Our air is world class.
