Choose the correct option in each question. In some questions you can select multiple options.
About this exercise type...The chemical lifetime of NOx in the boundary layer is approximately
| — | 1 hour |
| — | 20 hours |
| — | 6 hours |
| — | 36 hours |
The chemical lifetime of NOx in the upper troposphere is approximately
| — | a few hours |
| — | several days to a week |
| — | a day |
| — | a month |
The rapid breakdown of NOx leads to a large variation in its concentration. Urban areas can have concentrations in the order of
| — | 10 parts per billion by volume |
| — | 10 parts per million by volume |
| — | 10 parts per thousand by volume |
| — | 10 parts per trillion by volume |
whereas remote regions such as the upper troposphere and the boundary layers over remote areas of oceans can have concentrations in the order of
| — | 10 parts per billion by volume. |
| — | 10 parts per million by volume. |
| — | 10 parts per thousand by volume. |
| — | 10 parts per trillion by volume. |
The breakdown of NO2 can produce HNO3, which
| — | permanently binds NOx. |
| — | acts as a temporary reservoir for NOx. |
| — | can itself be a source of NOx. |
| — | is only produced during daylight. |
NB You can choose several options
During the day
| — | HNO3 is rapidly photolysed. |
| — | Reacts directly with CH4 or other hydrocarbons. |
| — | HNO3 uses up NOx. |
HNO3 acts as a sink for NO2
| — | more during the day. |
| — | equally during night and day. |
| — | more during the night. |
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