I don't understand...

While waiting for the streetcar today, I caught a glimpse (actually, couldn't miss it) of one of those advertising trucks that can be seen on their circuitous routes through the city. One ad read: "Place your ad here!" while another read rather ironically: "Cut emissions by 15-20%" or something like that. This very large truck, likely consuming tons of gas in the city, and spewing equally large amounts of emissions, is advertising for some earthy or green organization. Could they not have thought of less polluting forms of advertisement?

A billboard truck. I think we should start putting ads for air purifiers on cigarette packs.