MEV 015: Unit 02 - Air Quality and Its Impact

UNIT 2: AIR QUALITY AND ITS IMPACT

2.0 Introduction

This section introduces the concept of air quality and explains why clean air is important for health, environment, and well-being. It highlights how air pollution affects ecosystems, human health, and climate.

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2.1 Objectives

By the end of this unit, learners will be able to:

·         Understand different sources of air pollution.

·         Identify major air pollutants and their effects.

·         Learn how air quality is monitored and measured.

·         Understand air quality standards and regulations.

·         Know about indoor air pollution and its impact on health.

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2.2 Sources of Air Pollutants

Air pollution can come from various natural and human-made (anthropogenic) sources.

Natural Sources

·         Volcanic eruptions

·         Forest fires

·         Dust storms

·         Pollen from plants

Anthropogenic Sources

·         Industrial emissions

·         Vehicle exhaust

·         Construction activities

·         Burning of fossil fuels

Types of Sources

·         Stationary sources: Fixed locations like factories and power plants

·         Mobile sources: Vehicles like cars, buses, trucks

·         Area sources: Residential areas, agricultural fields

·         Line sources: Roads and highways with heavy traffic

Fugitive Emissions

Uncontrolled emissions that escape from leaking pipes, open equipment, or uncovered containers.

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2.3 Air Pollutants and Their Effects

Gaseous Pollutants

·         Carbon monoxide (CO): Affects oxygen transport in the blood

·         Nitrogen oxides (NOx): Causes respiratory issues and smog

·         Sulphur dioxide (SO₂): Irritates eyes and throat, causes acid rain

·         Ozone (O₃): Harmful at ground level, causes lung problems

Particulate Matter (PM)

·         Tiny solid or liquid particles suspended in the air

·         Includes PM₁₀ and PM₂.₅ — can enter lungs and bloodstream

·         Causes breathing problems, heart disease, and cancer

Criteria Pollutants

·         Pollutants identified by environmental agencies as harmful and used to assess air quality

·         Includes: CO, NOx, SO₂, O₃, PM, and Lead (Pb)

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2.4 Meteorology of Air Pollution

The behavior and movement of air pollutants depend on:

·         Wind speed and direction

·         Temperature and temperature inversion

·         Humidity

·         Topography (mountains, valleys, sea breeze, etc.)

These factors influence how pollutants spread and settle in the environment.

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2.5 Monitoring of Air Quality

Air quality is regularly checked using:

·         Air sampling equipment

·         Monitoring stations

·         Sensors and satellites

Data collected helps in assessing pollution levels and making decisions for pollution control.

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2.6 Air Quality Standards

National Ambient Air Quality Standards (NAAQS)

·         Set by MoEF&CC and CPCB in India

·         Define safe limits for pollutants in ambient air

·         Used to take action against polluting industries

Bharat Stage Emission Standards

·         Set emission limits for vehicles in India

·         Similar to European emission standards

·         BS-I to BS-VI: Each stage is stricter than the last

·         Help reduce vehicular pollution

Air Quality Index (AQI)

·         A number scale used to show the level of air pollution

·         Color-coded to indicate how safe or dangerous the air is
(e.g., Green = Good, Red = Very Poor)

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2.7 Indoor Air Pollution

Concept and Sources

·         Pollution inside homes, schools, offices

·         Caused by:

o    Cooking with biomass fuel

o    Smoking

o    Poor ventilation

o    Use of sprays and cleaning products

Effects on Human Health

·         Eye irritation, headaches, respiratory problems

·         Long-term exposure may cause asthma, lung cancer, heart disease

·         Especially harmful to children, elderly, and those with weak immunity