I've apparently never had asthma in my life, until I moved to Sydney, Australia for a while.

It's a city which _loves_ cars.

I used to cycle about 20 minutes to the office, the view was beautiful but the traffic was horrendous. I used to wheeze and struggle with breathing a lot more than usual. The doctor diagnosed me with "seasonal asthma" and gave me a ventolin prescription, which I've never felt the need to refill since leaving.

The doctor told me there was some phenomenon which made the air pollution worse, something about the reflection of the water from the harbor ? I wish I could remember what it was called.

It's anecdotal but that was my experience.