INGOMAR MIDDLE SCHOOL SCIENCE             NAME: ______________________                     
OZONE DEPLETION LAB                                       Period: ______ Date: __________     Score_____/ 10

      Ground level ozone comes from NOx (Nitrogen Oxides) and VOC (volatile organic compounds). Mix NOx and VOC in hot, sunny air and you get ozone.

 

About 50 % of NOx comes from mobiles sources such as on-road vehicles (30.7%) and non-road sources (19.7%). Stationary sources of NOx come from Power plants (25.8%), industrial (13.6%), and other (5.5%), industrial processes (3.8 %), and Miscellaneous (1 %)*.

   Only about 42 % of VOC comes from mobiles sources such as on-road vehicles (28.8%) and non-road sources (12.7%). Stationary sources of VOC come from solvents (32.9%), storage and transport of liquid fuels (6.9%), fuel combustion (5.7%), chemical and petroleum (5.0 %), other industrial processes (2.7%), fires (2.7%), waste disposal (2.3%) and Miscellaneous (.4%)*. Nonmethane hydrocarbons (NMHC)and reactive organic gases (ROG) and nonmethane organic gases (NMOG)are examples.

 

Nitrogen Oxides form when a mixture of nitrogen and oxygen is heated to a high temperature and cooled quickly.

 

N2  +  O2    è 2 NO  (reaction # 1)- nitric oxide.

 

2 NO  + O2  è 2 NO2 (reaction # 2)- nitrogen dioxide- a reddish brown color(smog).

 

OZONE( a cycle):

NO2  + sunlight  è NO  +  O  (reaction # 3)

 

O    + O         è O3        (reaction # 4)- Ozone

O3   + NO        è NO2 +  O2 (reaction # 5)- compounds feed reactions 3 & 4.

Draw cycle here:

 

 

 

 

 

But the cycle can be broken. Some kinds of VOC react with NO. These reactions quickly convert the NO produced in reaction # 3 back to NO2.  Without NO, reaction #5 can’t take place, and ozone produced by reaction # 4 accumulates.

Draw cycle here:

 

 

 

 

Test for ground ozone: Avoid wind, direct sunlight, and cloths.

Indicator papers change colors when exposed to chemicals, like for acidity. Wet the paper before taking a reading. Compare to color scale, it won’t match exactly. Plan an investigation of ozone concentrations here at I.M.S. Decide where to place test cards.

 

Your investigation results:

 



Complete the “It’s Atmospheric!” crossword puzzle and the ozone depletion worksheet.


Brainstorm ways to reduce emissions:

See: Aerosols/Ozone/CAPC, Air Quality, Airwaste/pollution, AQMD, EPA VOC, EPA-Ozone, Ozone