| A | B |
|---|
| smog | a fog made heavier and darker by smoke and chemical fumes |
| pollution | waste matter that contaminates the water or air or soil |
| acid rain | acid precipitation in the form of rain |
| ozone | a triatomic very reactive form of oxygen that is a bluish irritating gas of pungent odor |
| carbon monoxide | poisoness gas that is the result of incompletement combustion of carbon |
| carbon dioxide | heavy odorless gas present in the atmosphere and formed from the decay and combustion of organic substances |
| ozone layer | a region of the upper atmosphere, between 10 and 20 miles in altitude, containing a relatively high concentration of ozone that absorbs solar ultraviolet radiation in a wavelength range not screened by other atmospheric components |
| pollutants | pollution causing agents |
