Air Quality & Respiratory Health Study
- Lane Cove Tunnel Health Investigation

Introduction

A health study is being conducted amongst residents in the community surrounding the Lane Cove Tunnel to determine whether respiratory health is affected by changes in traffic related air quality in the area. The study is being undertaken by the Woolcock Institute of Medical Research and is funded by the CRC for Asthma and Airways and the NSW Health Department.

The investigation includes a series of four studies looking at respiratory health and related symptoms in the population surrounding the Lane Cove Tunnel, both before (in 2006) and after the opening of the road tunnel (in 2007). The investigation has been extended to include a third round of testing (in 2008), due to the delay in road changes to Epping Road which occurred up to March 2008.

For each of the studies, data collection is taking place at the same time of year, to try to ensure that the results are not influenced by seasonal changes in the weather, pollen exposure or the prevalence of respiratory infection in the general community. The strength of the studies lies in their cohort or before-and-after design. Repeating the same measurements in people and the environment allows us to see if any change in these measurements can be linked to factors that have changed between the testing periods eg traffic conditions and air quality.

While there are many published studies examining the relation between air pollution levels and health, these studies only provide indirect evidence about the likely impact of changes in pollution, both beneficial and adverse, due to the opening of new motorways, tunnels and ventilation stacks. This investigation offers a unique opportunity to provide direct evidence of any effect on the respiratory health of people residing in the Lane Cove, Ryde and Willoughby areas, due to changes in air pollution from the road changes. This will be important for urban planners, government and the general public in New South Wales, as well as nationally and internationally.

Timeline for studies

Data collection for the study for the period before the tunnel opened was collected during June-December 2006. Follow-up data collection after the tunnel opened in March 2007, was collected from June-December 2007. A third round of data collection is currently taking place with fieldwork occurring between June-December 2008. Cleaning, checking and analysis of the data will occur during 2009, with the study being completed in 2010.

Main aims of the studies

  The main aims of the study as a whole are:

• To establish whether changes in air quality occurring between the year before the tunnel opens and the two years after the tunnel opens have an influence on community health.

• To establish whether any changes in community health are specifically attributable to emissions arising from the ventilation stacks.

Description of the studies

The four studies are summarised below. Three of the four studies are being conducted in four distinct areas around the Lane Cove Tunnel. The areas have been chosen to represent varying levels of air quality and also include a control area. For more detailed information on each of the studies please refer to the Protocol document on this website.

• Questionnaire survey

Residents in the selected areas are being interviewed about recent respiratory and irritant symptoms, the severity of symptoms, and the use of respiratory medications. The questionnaire also includes questions about the home environment and other factors that may be related to respiratory health. The survey has been conducted in 2006 and 2007, and is currently being conducted during June-December in 2008. The 2007 and 2008 data will represent the time period after tunnel opening.

Using this survey we will measure the number of people who have respiratory and other symptoms in 2006, in 2007 and again in 2008. Statistical analyses will be conducted to determine whether there is any association between changes in the number of people who report symptoms in each area and changes in air quality.

• Symptom and peak flow diary study

A sub-group of the Questionnaire Survey participants have been recruited into a second study involving the recording of twice daily peak flow measurements (a measure of lung function) and symptom diaries. Each person recruited into the Diary Study recorded measurements twice daily for 9 weeks in 2006, and 2007, and we are currently following them up again to collect data for 2008.

From the Diary Study we will investigate whether any short-term changes in lung function or symptoms are associated with short-term changes in air quality. Data from 2006 will be compared with data from 2007 and 2008 to determine any overall changes from year to year.

• Estimating exposure to traffic-related air pollution

This study is measuring changes in exposure to nitrogen dioxide (NO 2), which is being used in this study as a marker for traffic-related air pollution. NO 2 concentrations are being measured by using passive NO 2 samplers provided and analysed by the CSIRO. The samplers are small, the size of a 20c piece and can be used to sample outdoor air, indoor air, or personal air (when a person wears the sampler). Using these samplers, ambient concentrations of NO 2 are being measured in various locations around the study area to assess how NO 2 varies over short distances and on streets with different traffic flows. These measurements will be used along with other traffic-related data (eg traffic density, distance to main road, etc) to estimate NO 2 levels for all participants in the Questionnaire and Diary Studies.

Several other sources of air quality information are being used for this study, including data from several fixed site air quality monitors located in the area. We are also using estimates of exposure to air pollutants for all households in the study that are based on modelling conducted by the CSIRO. This CSIRO work includes modelling for NO 2 as well as particulate matter (PM 2.5, PM 10).

• Short term effects of exposure

The fourth study is focussing on the potential short-term effects arising from exposure to emissions from the ventilation stacks. This is an experimental study which is based on a study conducted in London. It involves a small number of volunteer subjects attending one of a number of locations around the western ventilation stack and another (control) location on six occasions during each year of testing. During each testing occasion, subjects undergo gentle exercise (walking) for a period of two hours, and undergo lung function testing as well as record irritant symptoms.

These data will be used to examine whether changes in air quality in the vicinity of the ventilation stack between 2006 (pre-tunnel), 2007 and 2008 (post tunnel opening), have any acute (short-term) effects on respiratory effects.

Steering group

The Lane Cove Tunnel Health Investigation Steering Group has been formed by the NSW Health Department (NSW Health) toprovide expert advice to the Chief Health Officer and the Investigators on the design, analysis and interpretation of the health investigation.

The members of the steering group have been chosen for their specific expertise and their role is to provide advice on the design, implementation, analysis or interpretation of the investigation relating to their field of expertise. Steering group members bring the following areas of expertise to the study:

• Environmental epidemiology
• Air pollution-asthma epidemiology
• Air quality measurement and modelling
• Biostatistics.

The Director of Public Health for Northern Sydney Central Coast Area Health Service has also been invited onto the Steering Group. This person has expertise in air pollution and asthma epidemiology as well as being Director of Public Health for the area covered by the study. The community interest is represented by a representative chosen by Lane Cove Council. This representative is an air quality expert.

Publication of results

We will seek to have the study results published in peer-reviewed scientific journals. This will be useful for a number of reasons:

• it enables the results to be published in a public forum which is accessible to anyone;
• it enables independent scientific review of the methodology, analyses and results of the studies (most likely by overseas experts);
• it will contribute to current scientific knowledge in this area.