MYP Individuals & Societies Pollution Notes

Why Is Pollution A System Problem With Multiple Causes And Stakeholders?

1. Pollution occurs when human activities (production, transport, energy use, agriculture, waste disposal) create outputs that ecosystems cannot absorb without harm.
2. This means pollution is rarely caused by one factor, instead it emerges from a system:
   1. Sources (vehicles, factories, power plants, farms, households)
   2. Pathways (air currents, rivers, groundwater flow, food chains)
   3. Receptors (people, habitats, buildings, crops)
   4. Impacts (health costs, ecosystem damage, economic losses)
   5. Responses (laws, technology, planning, behaviour change)

How Does Air Pollution Concentrate In Cities And Affect Health?

1. Air pollution is one of the most significant environmental risks to health.
2. Air quality is commonly reported using the Air Quality Index (AQI), which converts pollution levels into a single scale to show how harmful the air is to human health, with higher values indicating greater risk.

PM2.5 is a key urban indicator

1. PM2.5 (particulate matter smaller than 2.5 micrometres) is one of the main pollutants used to calculate the AQI.
2. AQI values often rise sharply when PM2.5 concentrations increase, because these particles are small enough to penetrate deep into the lungs and enter the bloodstream.
3. Many cities track air quality using average PM2.5 concentration measured in $\mu g/m^3$.
4. Some countries have very high average PM2.5 levels in urban areas (for example Pakistan, Qatar, Afghanistan, Bangladesh, Egypt), while others are much lower (for example Australia, Brunei, New Zealand, Estonia, Finland, Canada).

Urban green spaces help regulate air quality

1. Urban growth often reduces green space as land is needed for housing and infrastructure.
2. This can worsen air pollution because vegetation can help trap particulates and support cooler, healthier urban microclimates.

How Does Traffic Congestion Increase Emissions And Urban Stress?

1. Congestion has social, economic, and environmental impacts.
2. In fact, the average US commuter wastes 42 hours per year stuck in traffic (and the situation can be similar or worse in many less economically developed contexts).

Why congestion happens in different places

1. In many lower economically developed countries (LEDCs), congestion often rises quickly due to rapid urban growth without adequate forward planning and infrastructure, plus rising incomes increasing vehicle ownership.