Photochemical Smog: Rising Challenges

Photochemical smog is a mixture of pollutants that are formed when nitrogen oxides and volatile organic compounds (VOCs) react to sunlight, creating a brown haze above cities. It tends to occur more often in summer, because that is when we have the most sunlight.

Effects and Mitigation of Photochemical Smog

• Photochemical haze has a harmful impact on both the environment and people in a number of ways.
• The molecules produced when the chemicals and hydrocarbons combine to irritate the eyes.
• Because ground-level ozone cannot be eliminated, atmospheric radicals interfere with the nitrogen cycle.
• Ozone has the potential to be extremely dangerous for people when it is present at ground level.
• Reduced eyesight and shortness of breath are two additional side effects of photochemical smog.
• The main method of lowering the levels of nitrogen oxides is by a process called ‘catalytic reduction’, which is used in industry and in motor vehicles.
• Biofuels have been the focus of attention as a possible means of reducing greenhouse gas emissions and noxious urban emissions from transport.
• Hydrogen-powered and electric vehicles are cleaner options for vehicles.
• The most effective way of reducing the amount of secondary pollutants created in the air is to reduce emissions of both primary pollutants.
• There are various ways to reduce VOC emissions from motor vehicles. These include the use of liquefied petroleum gas (LPG) or compressed natural gas (CNG) rather than petrol, decreasing distances vehicles travel by using other modes of transport, such as buses and bikes, and implementing various engine and emission controls now being developed by manufacturers.

Gothenburg Protocol 1999

• The Gothenburg Protocol was established to address pollutants that cause acidification and ground-level ozone.
• It established limitations on air pollutants, such as volatile organic compounds, sulphur dioxide, nitrogen oxide, and ammonia, which are harmful to both human health and the environment.
• For the primary air pollutants, the Protocol sets legally binding pledges to reduce emissions through 2020 and beyond.
• This multi-pollutant, multi-effect protocol is meant to eventually replace the older protocols that cover the same pollutants.