chemicals remain in the atmosphere for approximately one hundred years, although it depends on the type of CFC. Once it was determined that CFCs were a problem, the Montréal protocol was developed, which helped to reduce the numbers of CFCs we release into the atmosphere. Because of this protocol, we no longer have aerosol spray cans but instead use aerosol pumps, which do not have CFCs in them. One problem, however, is that we may not be able to completely recover from the ozone losses we have already achieved. Now, getting back to air pollution and ozone, you need to talk about ground-level ozone or what we call bad ozone. Ozone near the earth at its surface can be a strong irritant to the lungs. Children, elderly persons, and those with lung diseases are particularly susceptible to the effects of ozone near the ground. Ozone is the main chemical you will see in smog. How to get all of this ozone? As mentioned, it is primarily caused by chemical reactions we see between two types of molecules. These are nitrogen oxides and VOCs or volatile organic compounds. In other words, when you mix emissions from cars, large boilers, power plants, chemical plants, and refineries, you will get ozone but only if it reacts with sunlight. Once made, ozone can travel for very long distances. The effects of ozone are largely related to the lungs. It is a chemical irritant that can cause irritation of the respiratory passages, inflammation of the same, coughing, chest pain, and worsening of pre-existing lung diseases. High levels of ozone will also affect ecosystems of all types, particularly those with a lot of vegetation and wildlife.
ROLE OF WIND AND INVERSIONS ON AIR POLLUTION We have talked briefly about thermal or temperature inversions. Where they become more important is when talking about air pollution in urban areas. Let's first talk about these thermal inversions and why we get them. We need to understand this because air quality and our weather are tightly connected in many ways. A temperature inversion involves the situation where cool air is trapped beneath warm air. You know by now that this is not it normally works. When this happens, the cool air
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