Its conclusion was that:
…there is sufficient evidence that exposures to traffic-related air pollution cause asthma exacerbation in children and suggestive evidence that they might cause other health effects.
…the zones most impacted by traffic-related pollution are up to 300 to 500 meters from highways and major roads
How do they define “major”? It appears they’ve used the metric of 10,000 vehicles per day.
The latest VicRoads Traffic System Performance report doesn’t give specific figures for particular roads, but does provide average lane occupancy figures (in terms of both cars and people), from which one can derive a very rough average number of cars on each type of road:
- Freeways 28,485 cars per lane per 24 hours
- Divided arterials 13,180 cars per lane per 24 hours
- Undivided arterials 11,063 cars per lane per 24 hours
- Undivided arterials with trams 11,361 cars per lane per 24 hours
But this is very rough. The vehicle count figures appear to include only cars, not other vehicles. Obviously roads around Melbourne vary enormously, and the lane occupancy figures apparently include buses and trams, so the number of vehicles will be a fair bit lower on better-served PT routes (such as the figure for roads with trams). And the level of congestion on each road would also directly effect the emissions, of course.
I do live near some main roads — about 100 metres from one, and about 400 metres from another. Fortunately, being in an area of Melbourne settled before the domination of the car, they are only one lane in each direction, and far enough out of the city centre that clear ways do not apply.
In VicRoads parlance, they would be undivided arterials. I suspect they are below the average in terms of traffic, but whether they are under 10,000 vehicles per day or not, I don’t know.
While Melbourne’s air quality is apparently quite good compared to some cities, obviously the air quality anywhere in urban areas isn’t going to be as good as it is in most rural areas.
But I’m thankful I don’t live close by to much wider and busier roads such as Nepean Highway (4 lanes in each direction), North Road (3 lanes in each direction), the freeways, or the fat outer-suburban roads like Springvale Road (3 lanes each direction).
And I’m rather glad for my nephew and my niece that my sister has moved from her house in East Brighton, which was less than 100 metres from the Nepean Highway. I must ask her if there’s been any noticeable difference in the kids’ health.