Cities aren’t the same nowadays when cars don’t regularly backfire on streets, and buses and trucks don’t bletch out black smoke.

It’s only been 10 years since they switched over low-sulfur diesel on buses and trucks to dramatically reduce the black smoke, and era of streets filled with old cars running carburetor engines out of tune is only 15 years or so ago.

Then again, I’m too young to remember when most city buildings were covered with thick black soot from the smoking engines.