Lecture 3 Flashcards
Residence time (RT) is
how long a substance stays in the “sink”
What is the formula to calculate RT
Total amount of substance / rate of inflow or outflow
How to calculate the mass of a gas
Weight of atmosphere (15X10^15) X % of gas in the atmosphere X Atomic weight of element / Average weight of elements (28.8)
The longer the RT is what can we conclude about the gas
1) it will be well mixed in the atmosphere
Long residence times results in what issues
Global
Short residence times result in what issues
Local
Water has what RT
14 days
CO2 has what RT
44 years
N2 has what RT
12 million years
A Hazard is
A set of circumstances that may cause harmful consequences
A Risk is
the probability (Numerical values) that represents the likelihood that something unpleasant will result from a hazard
Risk is measured from
0 to 1
True or False; To reduce a risk one must incur a cost
True
Risks can be sorted into how many groups?
3
What are the groups that risks can be sorted into
1) Plenty of data available
2) Those for which we have sketchy evidence available, but for which the relationship cannot be established with certainty. Have some data but not for a long period of time
3) Those for harmful events which have not yet happened
