. -- >> i am barbara graves, i live next door to an academy building and i will divorce myself from my feelings of positive creativity and contributions to the community that the academy brings and think about for a moment as one of the largest landowners in the city. what this means is some responsibility comes with that position. and if we divorce ourselves for the moment, this is pollution where we don't know the source. when you are talking about the academy -- we know where the pollution is coming from. a single transit bus, even with a modest filter and biodiesel, puts out approximately 0.8 lbs. of black carbon a year. this is a lot, and when you think that the water source will be depleted by climate change, the production of black carbon makes a big difference. there are ways to change this and one thing is to -- the previous speaker, i can tell you what i dust in my house, my window is right by the bus stop, for the academy of arts. i don't give brown dust, i get black dust. this is a possible carcinogen, and it contributes to climate change. this is not radical thinking for a