What is the differnce between a food chain and a food web

A food web is much.. larger?

A food web is formed out of multiple food chains; It follows multiple paths of nature.

While a food chain merely follows one.

Air pollution: “combustion results in gases such as nitrogen oxides, nitrogen dioxide and particulates. the main causes of air pollution include transport, domestic combustion and industrial processes. pollutants from these sources can cause problems in the immediate vicinity and a distance away.”