Source and meteorological influences on air quality (CO, CH₄ & CO₂) at a Southern Hemisphere urban site

Significant short-term positive trends in clean air CH4 (5.4 nmol mol−1 a−1) and CO2 (1.9 μmol mol−1 a−1) were consistent with the long-term global average trends. Polluted Wollongong air was investigated using wind-direction/wind-speed clustering, which revealed major influence from local urban and industrial sources from the south. High values of CH4, with anthropogenic deltaCH4/ΔCO2 enhancement ratio signatures, originated from the northwest, in the direction of local coal mining.

A pollution climatology was developed for the region using back trajectory analysis and deltaO3/deltaCO enhancement ratios. Ozone production environments in austral spring and summer were associated with anticyclonic meteorology on the east coast of Australia, while ozone depletion environments in autumn and winter were associated with continental transport, or fast moving trajectories from southern latitudes. This implies the need to consider meteorological conditions when developing policies for controlling air quality.