5. Before vehicle emissions were well-regulated CO emissions were 66 g/mile. Assume this emission rate applies for an airshed. The airshed has dimensions of 9 km by 18 km with wind speeds of 1.5 m/s parallel to the longer dimension. There is a temperature inversion at 100 m. The average vehicle miles traveled is 800,000 miles each hour between 5 AM and 8 PM, and the concentration of CO before the morning rush hour and the incoming wind concentration are both 200 ppb. Temperature is 0 °C and pressure is 0.9 atmospheres. a. Find C0 and Cin in mg/m3 . b. What is the pollutant residence time in the box? c. If morning rush hour starts at 5 AM. What is the CO concentration seven hours later?

CALINE4 Model and Geographical Information System were used for

the present study to predict the CO concentrations and prepare thematic

maps for the study area.

CALINE4 is a latest model that predicts the concentration of carbon

monoxide impacts near the roadways. The California Department of

Transformation (CALTRANS) developed the model and its purpose is to help

planners protect public health from the adverse effects of carbon monoxide.

The model predictions along with the aid of GIS based model help to arrive at

air shed levels of carbon monoxide. CALINE4 is a simple line source

Gaussian plume dispersion model. The user defines the proposed roadway

geometry, worst-case meteorological parameters, anticipated traffic volumes

and receptor positions to predict the concentrations of pollutant.

CALINE4 is graphical with windows based user interface, designed to

ease data entry and increase the online help capabilities. The model was

developed for predicting the concentrations of relatively inert pollutants such

as carbon monoxide and it is now used for several other pollutants like NO2

and SPM. The model is based on fine tuned Gaussian diffusion equation and

it employs mixing zone concept to characterize the pollutant dispersion over

the roadways. Given the exhaust emission concentrations, meteorology and

site geometry, the model can predict the concentration of pollutants for any experimentation

Explanation: