ESS Unit 6.3

What is photochemical smog?

A type of air pollution formed when sunlight reacts with nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the atmosphere

Define primary pollutants and give some examples.

Pollutants emitted directly from a source, such as carbon dioxide, carbon monoxide, sulphur dioxide, nitrogen oxides, and particulates from vehicle exhaust.

Define secondary pollutants and give some examples.

Pollutants formed when primary pollutants undergo reactions in the atmosphere. Examples include ozone, acid rain, and peroxyacyl nitrates (PAN).

What are the main human sources of nitrogen oxides?

Emissions from vehicles, industry, and power stations

What are the main natural sources of nitrogen oxides?

lightning

What are the main human sources of volatile organic compounds (VOCs)?

ndustry, vehicles, solvents, and forest fires

What are the main natural sources of volatile organic compounds (VOCs)?

volcanos

How does ozone form in photochemical smog?

Sunlight triggers reactions between nitrogen oxides and VOCs, leading to the formation of ozone.

What are peroxyacyl nitrates (PAN)?

Secondary pollutants formed in photochemical smog that are harmful to plants and human health

What is a thermal inversion and how does it contribute to smog?

A weather condition where a layer of warm air traps cooler air near the ground, preventing pollutants from dispersing.

What are the health impacts of photochemical smog?

Respiratory problems (coughing, wheezing, asthma), eye irritation, reduced lung function, and increased risk of lung disease and premature death.

How does smog affect the environment?

Damages plants by disrupting photosynthesis, reduces crop yields, and can damage materials like rubber and plastics.

Restoration Technique

Phytoremediation

examples of Phytoremediation

• Indian mustard: Effective at removing heavy metals like lead and cadmium.  

• Willow trees: Can absorb pollutants like arsenic and hydrocarbons.  

• Sunflowers: Effective at removing radioactive contaminants.

Phytoremediation

is a green technology that utilizes plants to clean up contaminated soil and water.

strengths of Phytoremediation

• Environmentally Friendly: Utilizes natural processes to clean up pollutants.  

• Cost-Effective: Often less expensive than traditional methods.  

• Aesthetically Pleasing: Can improve the appearance of degraded areas.

limitations of Phytoremediation

• Time-Consuming: Can take years to achieve significant results.

• Site-Specific: Requires careful selection of plant species and site conditions.  

• Limited Effectiveness: May not be suitable for all pollutants or sites

Replace (DONT DO)

• Use Organic Fertilizers: Replace synthetic fertilizers with organic alternatives to improve soil health.

• Choose Resistant Crop Varieties: Plant crop varieties that are resistant to pests and diseases.

• Utilize Biological Control: Use natural predators and parasites to control pests.

Reduce

• Minimize Pesticide Use: Use integrated pest management (IPM) techniques to reduce reliance on chemical pesticides.  

• Conserve Water: Implement efficient irrigation practices to reduce water consumption.

• Reduce Fertilizer Use: Use precision agriculture techniques to apply fertilizers only when and where needed.

Effects on Plants

• Reduced Photosynthesis: Key components of smog, such as ozone and peroxyacetyl nitrate (PAN), can damage plant tissues, particularly leaf surfaces. This damage reduces the plant's ability to photosynthesize, leading to decreased growth and productivity.  

• Stunted Growth: Exposure to smog can stunt plant growth, affecting both agricultural crops and natural vegetation.  

• Increased Susceptibility to Diseases: Weakened plants are more vulnerable to diseases and pests.

Effects on Human Health

• Respiratory Problems: Smog can irritate the respiratory tract, causing coughing, wheezing, and difficulty breathing.  

• Heart Disease: Exposure to air pollutants in smog can increase the risk of heart attacks and strokes.  

• Eye Irritation: Smog can cause eye irritation, including redness, watering, and burning.  

• Reduced Lung Function: Long-term exposure to smog can lead to reduced lung function and increased risk of lung diseases like asthma and bronchitis.

Effects on Agriculture

• Reduced Crop Yields: Smog can damage crops, leading to reduced yields and lower quality.  

• Delayed Maturation: Plants exposed to smog may mature more slowly, affecting harvest times and overall productivity.

• Economic Losses: Reduced crop yields and increased costs associated with managing smog-related damage can lead to significant economic losses for farmers.