Thanks to a friendly reader who reminded me that today was a Spare the Air day, I'm on the train instead of the bus, which means a shorter, cleaner and more comfortable commute. Typically, it would also mean a more expensive commute, but because it's the first Spare the Air day of the season, the train is free.

Unlike last year's campaign, which only offered free rides in the morning for the first five Spare the Air days, this year's campaign is offering free rides all day for the first three Spare the Air days.

The new promotion makes more sense. Who wants a free trip to work only to be stuck at the office unless he or she pays to get home? It made sense if you were a transit agency trying to make money on an environmental cause, but it made little sense if you were a commuter.

If the number of fellow passengers is any indication, the promotion seems to be working. Although the train is still rather empty as we approach downtown San Jose, it's less empty than usual. By Mountain View, I'm guessing the train will be well on its way to full occupancy. I've seen the crowds at the Mountain View station and it puts the south county communities to shame.

As a note, last year's first Spare the Air day came at the end of July, one month later than this year's first smoggier-than-usual day. That can't be a good sign, but on a positive note, the five-day air quality forecast shows lower smog and ozone levels for the weekend. I hope they remain low. I prefer clean air to free rides.

By the way, somebody just started trimming his nails on the train. That is nasty. I'm cringing at the sound of his clippers. Ugh! I can't tell you how happy I am that my stop is coming right up.