NIWA: Traffic-Related Air Pollution At Auckland Schools

NIWA scientists are investigating traffic-related air pollution at Auckland schools

NIWA scientists are investigating traffic-related air pollution and ultra-fine particles at Auckland schools, inside and outside classrooms, to help understand the long-term health effects on children.

In 2007, findings revealed that children who lived within 500 metres of a Los Angeles freeway grow up with significantly reduced lung capacity. This makes them more susceptible to heart disease and lung disease.

Cars and trucks are the most significant source of ultra-fine particles, and air pollution, in many cities. New findings suggest that ultra-fine particles (the tiny flecks of soot and fumes that come from traffic and wood smoke) are more toxic than larger particles.

So far, NIWA scientists have conducted research in two schools in the Auckland area. They hope to survey two more schools in central Auckland in the next year.

The research Between April and June 2011, NIWA scientists ran an observational research programme in South Auckland. Their aim was to gather data on emissions from motorways, assess what proportion of potentially health-damaging emissions comes from the motorways, and determine how far the emissions travel.

The research also aims to assess what proportion of emissions penetrate into the classrooms. “We are measuring inside and outside the schools. We have to look at the other sources of particles inside the classroom. Things that might produce particles inside the school are solvents and cleaners, which generate small particles. When the children are moving around they generate a lot of dust particles,” says NIWA air quality scientist Dr Ian Longley.

The NIWA scientists gathered air samples every minute on the school grounds and inside the school classrooms.

The first school the scientists monitored was Waterlea Public School in Mangere Bridge, two kilometres from the nearest motorway, which was the ‘control’ or background school.

“This school was selected because we knew that there was not much traffic around that school. Measurements were taken inside Waterlea Public School classrooms for two weeks, and on the school grounds for four weeks,” says Dr Longley.

The scientists then moved to Wymondley Road School in Otara for three weeks. “Wymondley Road School is sited on the west side of the Auckland Southern Motorway, so we have to split the [air quality] data up into westerly winds and easterly winds. We found that the easterly winds and the proximity to the motorway made a big difference. Pollution and particle levels are] significantly elevated in easterly winds, as we are right next to the Highbrook Drive interchange with six lanes and two slip roads. A lot of trucks use this interchange to enter the motorway,” says Dr Longley.

Understanding the results The survey results will be compared with the results found in a similar study in southeast Queensland.

A thorough analysis of the data will be completed in 2012. The NIWA scientists will work with medical researchers to find out what exposure to these levels of ultra-fine particles will mean for the health of our school children.

Findings from recent American research reveal that living near a motorway caused reduced lung growth in 10–18 year olds. In another study, children aged 0-14 in neighbourhoods near to heavy truck traffic had increased risks of asthma hospitalization. “Children are vulnerable, and we don’t know the impact of these pollutants on New Zealand children,” says Dr Longley.

The results of this survey will be available to inform transport and public health policy in the future. “We need to find out how much health risk is due to the motorway and how much is due to other causes,” says Dr Longley.

NIWA's Auckland research is carried out in collaboration with the University of Canterbury. The Australian study is being led by the Queensland University of Technology (QUT). This research was funded by the Ministry of Science and Innovation.

Other information about this item:

Measuring the air we breathe

1. Instruments in the school grounds Air-quality monitoring instruments were strategically positioned within the school grounds. The air-quality monitoring stations use four instruments to measure multiple pollutants. The main roadside contaminants that impact on health are:
• carbon monoxide, which is largely emitted from petrol cars
• particulate matter (the small flecks of soot, fumes and dust that come from traffic and wood smoke)
• ultrafine particles (the smallest particles which come from traffic, especially diesels, and penetrate deeply into the lungs).

2. The monitoring bike Woodrow (Woody) Pattison,(a University of Canterbury PhD student), conducted trips in the morning and afternoon using a bike his grandfather gave him.. He was cycling, walking or driving the routes that the school children would use to get to and from school. This allowed the instruments to gather data on the levels of pollutants from local traffic, including the motorway.

Woody’s quarter-century old bike had a basket on the front containing his measuring equipment. The cellphone in the basket used GPS to record where he had been. He took a photo every three seconds and recorded voice logs of what he saw as he travelled. A dust monitor recorded background concentrations of wood smoke, and a condensation-particle counter recorded ultra-fine particles representative of fresh vehicle emissions. The basket also contained a carbon monoxide sensor.

3. Methods used to investigate indoor exposure inside the classroom The indoor instruments measured the same contaminants as the outdoor air-quality monitoring stations.

The indoor instruments gathered data every minute and at the end of every week this ‘indoor’ data was sent back to the office at NIWA in Auckland. The data could then be compared with data from outside the classroom.

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