1.1. Air-Water Exchange

Try these first

1. 1.

   Define air-water exchange.

   Hint

   Think about the processes in lakes and rivers.

2. 2.

   What is a mass transfer coefficient?

   Hint

   It helps measure rates of evaporation.

3. 3.

   What is the primary purpose of studying air-water exchange?

   • To improve air quality
   • To understand pollutant behavior
   • To increase evaporation rates

   Hint

   Consider why this exchange affects the environment.

4. 4.

   True or False: The mass transfer coefficient can be neglected if the water is well-mixed.

   • True
   • False

   Hint

   Think about the role of coefficients in calculations.

5. 5.

   A lake with a diameter of 100 meters has a chemical concentration of 200 ppm. Calculate how long it will take for the concentration to decrease to 50 ppm, assuming a constant evaporation rate.

   Hint

   Consider the relationship between concentration and time.

6. 6.

   Given a Gaussian dispersion equation and wind speed, calculate the expected concentration of a pollutant at a height of 1 meter and distance of 300 meters from the source.

   Hint

   Identify all necessary variables in your equation.