In environmental science, why is burning coal considered a major source of air pollution and environmental harm?

Introduction / Context:
Coal has been an important energy source for industry and electricity generation, but it is also widely recognised as a major contributor to air pollution and climate change. Understanding exactly why coal combustion is so harmful helps explain many modern environmental policies and the shift toward cleaner energy sources. This question asks for the main scientific reasons that burning coal is considered a major source of pollution.

Given Data / Assumptions:

• The process under discussion is burning coal in power plants, households or industry.
• We focus on emissions released into the air during combustion.
• The options mention different gases, particulates and unrealistic claims about oxygen removal or smokeless burning.

Concept / Approach:
Coal is a carbon rich fossil fuel that also contains sulfur, nitrogen compounds and trace amounts of metals such as mercury, arsenic and lead. When coal is burned, carbon combines with oxygen to form large quantities of carbon dioxide, a greenhouse gas that contributes to global warming. Sulfur in coal forms sulfur dioxide, which can lead to acid rain and respiratory problems. Nitrogen in the fuel and air can form nitrogen oxides, which contribute to smog, acid rain and ozone formation. Incomplete combustion releases particulate matter (soot and ash) that can penetrate deep into the lungs. Trace metals are released in small amounts but can accumulate in ecosystems and pose health risks. Together, these pollutants make coal burning one of the dirtiest forms of energy production.

Step-by-Step Solution:
Step 1: Identify the main components of coal: high levels of carbon and variable amounts of sulfur, nitrogen and trace metals. Step 2: Recall that burning carbon produces carbon dioxide, which contributes to global climate change. Step 3: Remember that sulfur in coal forms sulfur dioxide when burned, which can cause acid rain and respiratory irritation. Step 4: Note that high temperature combustion produces nitrogen oxides from both nitrogen in coal and nitrogen in the air. Step 5: Recognise that incomplete combustion and ash release fine particulate matter that reduces visibility and harms lung health. Step 6: Understand that trace metals like mercury can be released into the air, later settling into water and soil where they accumulate in food chains. Step 7: Choose the option that correctly combines all these pollution components as the reason coal burning is so harmful.

Verification / Alternative check:
Environmental reports from agencies and scientific studies consistently highlight coal fired power plants as major sources of carbon dioxide, sulfur dioxide, nitrogen oxides, particulate matter and mercury emissions. Air quality regulations often set strict limits for these pollutants, and much of the control technology in coal plants is designed to capture sulfur and particulates. There is no credible scientific claim that coal fires are smokeless or that they remove all oxygen from the atmosphere. These facts confirm that the detailed multi pollutant explanation is correct.

Why Other Options Are Wrong:
The idea that coal fires are completely smokeless is false; coal combustion often produces visible smoke and particulates. Claiming that coal is the only fossil fuel with carbon is incorrect, because oil and natural gas also contain carbon. Saying that burning coal removes all oxygen from the atmosphere globally is unrealistic; while oxygen is consumed locally, it is not exhausted worldwide. The statement that coal cannot produce electricity and must be burned in open fields ignores the reality of coal fired power plants specifically designed for electricity generation.

Common Pitfalls:
Some people focus only on carbon dioxide and climate change when thinking about coal pollution, forgetting about sulfur dioxide, nitrogen oxides, particulates and heavy metals. Others may not realise that fine particulate matter and trace metals can be as harmful in the short term as carbon dioxide is in the long term. To answer exam questions correctly, remember that coal is problematic for both air quality and climate: it emits multiple harmful pollutants at once. A mental checklist of CO2, SO2, NOx, particulates and toxic metals will help you choose the most complete explanation.

Final Answer:
Burning coal is a major source of pollution because it Releases large amounts of carbon dioxide, sulfur dioxide, nitrogen oxides, particulate matter and toxic trace metals into the air.