[melony]

More likely would be tire particulates.

[sascha_sl]

Don't underestimate noise pollution. It's a very real stressor.

Though, what's more likely is that a child with mild ASD is more obviously autistic under stress, which leads to diagnosis earlier.

[labster]

Don’t underestimate particulate matter and ozone. Kills millions every year.

But the same theory could apply, as health-induced stress instead of distraction stress. Or both.

[sascha_sl]

Both seems plausible. I just wanted to note that noise pullution is often overlooked and much more impactful than people assume.