Levels of harmful PM2.5 particles in the air in Melbourne, where the Australian Open tennis tournament will be carried out starting Monday, have been somewhat elevated because of the bushfires that have been raging in the country since December.
Throughout January, air pollution has been above normal for the city, briefly reaching very unhealthy levels on Jan 15 before returning to levels of moderate pollution. Three more days in the month showed pollution levels deemed unhealthy. Except for the Jan 15 reading, Melbourne air quality in January can be compared to that of Beijing, where the air is at least moderately unhealthy to breathe a majority of the time.
A look at air quality in the town of Wangaratta, two and a half hours north of Melbourne, exemplifies the extreme effect wildfires can have on air quality if wind patterns work in a town’s disfavor. Wangaratta readings in January exceeded that of Indian capital Delhi, one of the most polluted major cities in the world - at times manifold. The city's readings also show how quickly air quality can change in the case of nearby wildfires.
Melbourne normally enjoys very good air quality, with only a few days a year even showing moderate pollution (particle count 50-100). Before the wildfire crisis, Australia was even found to be the country with the best overall air quality in the world in a ranking by Yale and Columbia universities.
PM2.5 refers to the concentration of particles with a diameter of less than 2.5 micrometers in the air. These particles are of most concern to human health because they can linger in the air for long periods of time and are easily inhaled.