EFFECTS OF AIR POLLUTION

• Some types cause global warming to speed up.
• Others cause global warming to slow down by creating a temporary cooling effect for a few days or weeks.

• Chlorofluorocarbons attacked and destroyed the ozone layer, producing holes that would allow dangerous ultraviolet light to stream through.
• In the 1980s, huge “ozone holes” started to appear over Antarctica => prompting countries to unite and sign an international agreement called the Montreal Protocol, which rapidly phased out the use of CFCs. As a result, the ozone layer—though still damaged—is expected to recover by the end of the 21st century.

• Air pollution includes greenhouse gases.
• Greenhouse gases cause global warming by trapping heat from the Sun in the Earth’s atmosphere.
• Some air pollutants slow down global warming
  • Cars, trucks, and smokestacks also release tiny particles into the atmosphere which are called aerosols.
  • They can be made of different things such as mineral dust, sulfates, sea salt, or carbon.
  • While different types of aerosols act differently in the atmosphere, the overall effect of aerosols is cooling.

• Smog is often categorized as being either summer smog or winter smog.

Summer smog is primarily associated with the photochemical formation of ozone. – During the summer season when the temperatures are warmer and there is more sunlight present, photochemical smog is the dominant type of smog formation.

Winter smog is during the winter months when the temperatures are colder, and atmospheric inversions are common, there is an increase in coal and other fossil fuel usage to heat homes and buildings. These combustion emissions, together with the lack of pollutant dispersion under inversions, characterize winter smog formation.

• Smog formation in general relies on both primary and secondary pollutants.

• It is a type of air pollution derived from vehicular emission from internal combustion engines and industrial fumes.
•  These pollutants react in the atmosphere with sunlight to form secondary pollutants that also combine with the primary emissions to form photochemical smog.
• In certain other cities, such as Delhi, smog severity is often aggravated by stubble burning in neighboring agricultural areas.
•  The atmospheric pollution levels of Los Angeles, Beijing, Delhi, Lahore, Mexico City, Tehran and other cities are often increased by an inversion that traps pollution close to the ground.

Impact on agriculture

• Erratic behavior of monsoon rainfall, including phenomenon of concentrated heavy rainfall on small number of days in localized area can be attributed to the rising air pollution, especially the increase in suspended particles in the atmosphere.
• An increase in the aerosol content in the atmosphere, a direct consequence of rising air pollution, is interfering with the stable cloud formation system and influencing rainfall patterns.
• These changes in cloud structure and cloud dynamics lead to sharp variability in rainfall, the kind of which is being witnessed very often in India in the last few years.
• The high pollution levels are not just changing cloud shape and size and depth, but also its microstructure.
• Also causes Plant diseases, pollutants get settled on crops/Fruits causing leaching of such pollutants inside fruits.

• When rain falls through polluted air, it can pick up some of the pollution and turn more acidic—producing acid rain.
• Air pollution converts the rain into a weak acid. Pollutants like NOx, SOx when mixed with rainfall creates acidic rainfall whose PH is less than 4.0.

Environmental Impact of Acid Rain:

• When acid rain accumulates in lakes or rivers, it gradually turns the entire water more acidic.
• Fish thrive only in water that is neutral or slightly acidic (typically with a pH of 6.5–7.0).
•  Once the acidity drops below about pH 6.0, fish soon start to die—and if the pH drops to about 4.0 or less, all the fish will be killed.
•  It also causes the death of forests, reduces the fertility of soil, and damages buildings by eating away stonework.

Effect on Health of humans, especially vulnerable populations like children, aged people.

•  The health effects caused by air pollution may include difficulty in breathing, wheezing, coughing, asthma and worsening of existing respiratory and cardiac conditions.
• Mortality: The World Health Organization estimated in 2014 that every year air pollution causes the premature death of some 7 million people worldwide.
• Cardiovascular disease: Air pollution is also emerging as a risk factor for stroke, particularly in developing countries where pollutant levels are highest.
• High numbers of premature deaths: Findings of ‘Know what you breathe’ report released by IIT-Delhi in collaboration with environmental NGO Centre for Environment and Energy Development (CEED)
  • Worsening air quality in the last two decades has emerged as one of the major reasons for high numbers of premature (earlier than the expected lifetime of the Indian population) deaths due to chronic exposure from pollution.
  • Annual mortality linked to air pollutionto be in the range of 150-300 persons per 1 lakh population.
  • Premature mortality burden would reduce by 14%-28% annually with the achievement of Indian air quality standards.
• Findings of the World Health Organization (WHO) report titled “Inheriting a sustainable world: Atlas on children’s health and the environment”
  • A polluted environment kills around 1.7 million children every year.
  • Every year, environmental risks such as outdoor and indoor air pollution, unsafe water, second-hand smoke, lack of sanitation and inadequate hygiene results in a quarter of all global deaths of children under five.