KAT I EPA G EI B E S S Y E A R 2O C T O B E R 2 N D , 2 0 1 4

5.7- Air Pollution

Assessment Statements

5.7.1. State the source and outline the effect of troposphere ozone

5.7.2. Outline the formation of photochemical smog

5.7.3 Describe and evaluate pollution management strategies for urban air pollution.

Statistics

The US is responsible for 30.3% of the world’s gas emissions

33% of Chinese people live in such polluted cities that it is the equivalent of smoking 2 packs of cigarettes a day

In Asia, the pollution and smog is so thick that on some nights, you can’t see the stars

Teachers in Mexico City have reported that, when their kids draw the sky, they don’t draw it as blue.

Causes

Smokestacks of factories and power plantsMotor vehiclesChemicals, fires, and volcanoesFumes from hairspray, paint spray, and

nuclear weapons

Source and impact of troposphere ozone

In the troposphere, the lower atmosphere, ozone is considered a pollutant

Volatile Organic Compounds (VOCs): Organic chemical compounds able to evaporate into gases and take part in photochemical reactions

The main sources of VOCs and nitrogen oxides: Road transport Solvent release from drying paint Glues or inks Petrol handling and distribution

Impacts on Humans

According to the UN, air pollution is the cause of 1 in 8 global deaths

In 2012, air pollution caused the death of around 7 million people world wide

Effects on childrenRange of effects

Impacts on forests and crops

Ozone concentrations are lower in major urban areas

Ground ozone affects plant photosynthesisCrop exposure to ozone levels above a 40 ppb

tends to affect extensive areas of arable farming

The formation of photochemical smog

Photochemical smog: Refers to the poor air quality caused by a mixture of nitrogen and VOCs

Persists for many daysDifferences between Mediterranean and

Monsoon

Summer Smog

Occurs on calm, sunny daysFormed when nitrogen oxides and VOCs react

in sunlightOzone pollution is greater outside the city

center

Winter Smog

Associated with temperature inversions and high levels of sulfur and other pollutants

Under cold conditions, cars operate less efficiently

Urban areas surrounded by high ground are especially at risk Air sinks in from the surrounding hills

Trends

Ground levels of ozone had rise substantiallyPreindustrial was 10- 15 ppbCurrent annual mean is 30 ppb in the UKDifferent factors can impact the ground levels

Effects of smog

Effects are immediateDecreased UV radiationEffects can range from:

Minor- Joint pain, eye irritation Major- Lung Cancer

Air Pollution in Bangladesh

Ranked 4th worst country with urban air pollution

Main causes: Vehicles Industries

Air Quality Management Project works under the Department of Environment

Has yet to implement a National Air Quality Standard

Banned buses more than 20 years old in Dhaka, failed to implement

Case Study: Mexico City

The average visibility has decreased from 1000 km in the 1940s to 1.5 km in the 2000s

Benefits of reducing ozone by 10%Main programmes used to combat air

pollution: Reduce the use of private vehicles Control of vehicle conditions Change of fuels Reduction of lead and sulfur in fuels Implementation of catalytic converters

Governmental approaches

Air pollution may change with administrations

The United States The EPA has set national air quality standards

China Banned cars, closed factories, relocated steel work

Activity

Research methods used by governments to reduce air pollution and create your own five step plan.