Air Quality

Subprojects (Project 7)

7.1 – Emission sources and air quality

Project Leader: Hugh Forehead, UoW

This subproject focused on ensuring a better understanding of the main sources of atmospheric trace gases and pollutants that impact on urban air quality. The principal target sources were:

1. Traffic related pollution
2. Smoke from hazard reduction burns, wildfires and wood-smoke from domestic heaters
3. Biogenic emissions from trees and shrubs (which react with traffic emissions to increase ozone and fine particulate matter in the atmosphere).

Traffic related pollution

Traffic emissions are a well-known source of air pollutants in urban areas worldwide. This project consisted of two main components:

1. Researchers created a modelling framework that standardises the interface between the major components of traffic emission modelling; namely traffic modelling, emission modelling and dispersion modelling. While jurisdictions may use different packages for each of these modelling components, the adaptability of such a standardised framework ensures the consistent and comparable outputs of emission modelling across jurisdictions.
2. Researchers evaluated low-cost sensors for estimating exposure to PM2.5 pollution at street level in Liverpool NSW. This location was chosen due to its significance as a rapidly expanding urban centre and the opportunities for taking advantage of a productive research relationship with the Liverpool City Council. This was particularly valuable for obtaining access to data and infrastructure. Researchers explored methods for estimating exposure of pedestrians using the networked sensors for PM2.5, noise, and traffic (people & vehicles) counters.

Key outputs: 

Smoke pollution and air quality

A major source of poor air quality in Australian cities is smoke from bushfires, hazard-reduction burns and domestic wood-burning. Researchers conducted an air-quality measurement study in Auburn, in Sydney’s west, over 18 months. The study found that although the highest pollutant concentrations were observed during periods of controlled burns, domestic wood heaters caused greater cumulative exposure to smoke than other sources.

In 2020, widespread smoke pollution from the ‘black summer’ bushfires covered one of CAUL’s measurement sites near Wollongong, NSW. Researchers observed three weeks of heavily smoke-influenced greenhouse gas and aerosol measurements. These findings can inform public messaging during extreme smoke events, particularly those that are long-lasting.

Despite the impacts of COVID-19, in situ and Darwin solar measurements have been able to continue, though extension of these measurements to measure further fire-related pollutants has been compromised. The measurements made to date are being prepared for publication for wider scientific use, and these, together with co-incident satellite measurements, are being analysed to look at the impact of Indigenous fire management practices in the Top End.

Key outputs:

Biogenic emissions and air quality

There is growing recognition of the importance of the chemicals emitted by trees (biogenic volatile organic compounds or BVOCs) on atmospheric chemistry and air quality within urban air-sheds (especially in cities surrounded by densely forested regions). Within Australia many of the major cities have very high levels of atmospheric VOCs that are predominantly emitted by vegetation within the cities and emissions originating from nearby natural forested regions. These chemicals react in the atmosphere leading to increased concentrations of fine particulates and ozone, causing poor air quality and adverse health impacts. Until recently, understanding of these important atmospheric impacts has been hindered by an almost complete lack of measurements of these biogenic emissions from Australian vegetation. Models of atmospheric composition (for air quality forecasting and for climate simulations) rely on assumptions about the amounts and types of these chemicals emitted into the atmosphere by our forests. There is strong evidence from these models that current estimates of the most important emissions are wrong by a factor of two or three.

In order to address some of these issues, CAUL researchers helped develop the COALA project (Characterizing Organics and Aerosol Loading over Australia). COALA is an ambitious, multidisciplinary project designed to study the emissions and atmospheric chemistry of Australian biogenic species in a native forest environment and as they interact with anthropogenic pollution.

Key outputs:

Subproject 7.3 – Indoor Air Quality

Project Leader: Anne Steinemann, UoM

In Australia, most human exposure to potentially hazardous air pollutants occurs indoors, particularly volatile organic compounds (VOCs) from fragranced consumer products such as cleaning supplies and air fresheners. However, no Australian regulations currently address VOC emissions from products indoors, even though they can be a primary source of both indoor and outdoor air pollutants.

Researchers at CAUL found that 33 percent of Australians experience health problems, such as asthma attacks, from exposure to fragranced products, a major source of indoor pollutants. Removing fragranced products such as air fresheners can reduce concentrations of indoor pollutants by up to 96%. Using fragrance-free rather than fragranced laundry detergent can also reduce emissions of potentially hazardous pollutants from dryer vents by up to 99.7%.

These findings are now available to decision makers at all levels, from householders to commercial building managers, and government agencies involved in pollution regulation and management. 

Key outputs:

Subproject 7.4 – Ambient Air Quality, Noise & Health

Project leader: Jane Heyworth, UWA

Noise pollution is the excessive sound level that can disturb human or animal life. Transport infrastructure and vehicles, cars, trucks, motorbikes, airplanes, and construction activity all contribute to ambient noise levels in cities. However, we do not have good data on environmental exposure to noise and our aim was to develop noise maps for Australian cities that allow us to estimate household (habitat) exposure to noise.

To meet this need, CAUL supported the development traffic-related noise maps for Perth, Sydney and Melbourne in collaboration with the Australian Catholic University and the Centre for Air pollution, energy and Health Research (CAR). These maps estimate daily exposure to noise from traffic across the three metropolitan areas.

The maps will be used in epidemiologic studies to estimate the exposure-response relationships between noise and health outcomes, which will be useful for local government in developing public health plans. The maps can also help city planners better pinpoint where to employ noise-minimisation strategies or where development should be avoided altogether, especially to protect vulnerable groups such as children.

Key outputs:

Subprojects (Project 1)

Subproject 1.1 – Extending air quality measurement/monitoring capacity

Project leader: Clare Murphy, UoW

This subproject developed measurement capacity in collaboration with research partners. It extended the measurements available to evaluate air quality and test our air quality models via a number of complementary research activities.

Key outputs:

Subproject 1.2 – Implementing state-of-the-science air quality modelling techniques for estimating human exposure to airborne pollutants

Project leader: Dr Elise-Andree Guerette, UoW

It is now well understood that, given the limitations of any particular air quality model, more reliable results are achieved with an ensemble of models. This subproject drew on the heritage of several groups to advance the reliability of modelling current and future air quality for Western Sydney.

Key outputs: 

Subproject 1.3 – Exploring potential measurement and modelling techniques for estimating human exposure to airborne pollutants

Project leader: Jane Heyworth, UWA

The ideal scale for measurements and modelling of air pollution is at the individual exposure level, since this is where the health impacts occur. This subproject responded to a natural community concern that modelling and measurement should capture what is actually happening to them.

Key outputs:

Subproject 1.4 – Clean Air Plan for Western Sydney

Project leader: Peter Rayner, UoM

This subproject synthesised work on ambient air quality in Sydney and the work on indoor air quality to formulate a Clean Air Plan for Western Sydney.

Key outputs:

Banner image: Melbourne sky. Credit: HKMAA via flickr (CC0 1.0)