Read each of the following passages and answer the items that follow. Your answers to these items should be based on the passages only.
With the great concern surrounding the destruction of the earth’s atmosphere due to air pollution, the immediate and direct harm caused to the human body is often overshadowed. While many are aware that our careless use of hazardous chemicals and fossil fuels may leave the planet uninhabitable in the future, most overlook the fact that they also cause real damage to our bodies at this moment. Such pollutants cause damage to our respiratory system, leading to the fluctuation of the lifespan of an individual depending on a number of conditions. Amongst these conditions are the individual’s specific geographic location, age and lifestyle.
In order to understand how air pollution affects our body, you must understand exactly what this pollution is. The pollutants that harm our respiratory system are known as particulates. Particulates are the small solid particles that you can see through a ray of sunlight. They are products of incomplete combustion in engines (for example, automobile engines), road dust and wood smoke. Billions of tons of coal and oil are consumed around the world every year.
When these fuels burn they release smoke and other by-
products into the atmosphere. Although wind and rain occasionally wash away the smoke given off by power plants and automobiles, much still remains. Particulate matter (soot, ash, and other solids), usually consists of unburned hydrocarbons, carbon monoxide,
sulphur dioxide, various nitrogen oxides, ozone, and lead. These compounds undergo a series of chemical reactions in the presence of sunlight, and the result is smog (a term used to describe a noxious mixture of fog and smoke).
The process by which these pollutants harm our bodies begins by simply taking a breath. While you may see pollutants such as particulates, other harmful ones are not visible. Amongst the most dangerous to our health are carbon monoxide, the nitrogen oxides, sulphur dioxide and ozone. If you have ever been in an enclosed parking garage or a tunnel and felt dizzy or light-headed then you have felt the effect of carbon monoxide (CO). This odourless, colourless, but poisonous gas is produced by the incomplete burning of fossil fuels, like gasoline or diesel fuel.
Which of the following questions is not answered in the passage?