What Is Ozone and How Does It Affect Any Ecosystem?

Ozone is a molecule composed of three oxygen atoms (O₃), a naturally occurring gas that plays a dual role in Earth’s environmental systems. Stratospheric ozone protects life by absorbing harmful ultraviolet radiation, while ground-level ozone damages ecosystems through respiratory harm and vegetation stress. The effect of ozone on any ecosystem depends entirely on where the gas exists in the atmosphere. This article explains what Is ozone and how does it affect ecosystems and how businesses can address ozone-related environmental risks through strategic ESG management.

What Is Ozone?

Ozone is a molecule made of three oxygen atoms bonded together, forming the chemical compound O₃. This naturally occurring gas exists throughout Earth’s atmosphere in varying concentrations. Unlike the stable oxygen molecule (O₂) that organisms breathe, ozone is highly reactive. The molecule breaks apart easily when exposed to other chemicals or energy sources, making ozone both a protective shield and a potential pollutant depending on atmospheric location.

“Ozone (O₃) is a triatomic oxygen molecule found naturally in Earth’s atmosphere. Stratospheric ozone protects ecosystems by absorbing ultraviolet radiation, while ground-level ozone forms from pollution and damages plant and animal health. The molecule’s reactive nature determines its environmental impact.”

Where Is Ozone Found in the Atmosphere?

Ozone exists in two distinct atmospheric zones, each producing opposite environmental effects. Understanding these locations helps businesses assess regulatory compliance under frameworks like the Securities and Exchange Board of India (SEBI) Business Responsibility and Sustainability Reporting (BRSR) requirements, which mandate disclosure of air quality impacts.

Stratospheric Ozone (Protective Ozone)

Stratospheric ozone forms a concentrated layer between 10 and 50 kilometers above Earth’s surface, with peak density occurring around 20-25 kilometers altitude. This ozone layer absorbs 97-99% of the sun’s harmful ultraviolet-B (UV-B) radiation before it reaches the biosphere. Natural oxygen molecules (O₂) split under intense UV radiation in the stratosphere, creating free oxygen atoms that combine with remaining O₂ molecules to form ozone. This protective ozone layer remains essential for terrestrial and aquatic ecosystem survival, preventing DNA damage in plants, animals, and microorganisms.

Ground-Level Ozone (Pollution Ozone)

Ground-level ozone accumulates in the troposphere, the atmospheric layer extending from Earth’s surface to approximately 10 kilometers altitude. Unlike stratospheric ozone, this lower-atmosphere ozone does not form from natural UV processes. Instead, nitrogen oxides (NOx) from vehicle exhaust and industrial emissions react with volatile organic compounds (VOCs) from solvents, paints, and petrochemicals under sunlight. The photochemical reaction creates ozone concentrations that damage respiratory systems, reduce crop yields, and degrade ecosystem health. Urban and industrial zones in India—including Delhi, Mumbai, and Chennai—regularly exceed Central Pollution Control Board (CPCB) ground-level ozone standards during summer months.

Characteristic	Stratospheric Ozone (Protective)	Ground-Level Ozone (Harmful)
Location	10-50 km above surface	0-10 km (troposphere)
Formation	Natural UV + O₂ reaction	Pollution + sunlight reaction
Function	Blocks UV radiation	Respiratory irritant, plant toxin
Ecosystem Effect	Protects life from radiation	Damages plants, animals, microbes
Regulatory Focus	Montreal Protocol (depletion)	National Ambient Air Quality Standards

This ozone-related understanding is part of the component of E in ESG, which businesses must be understood to balance the environmental impacts and make profit responisbly!

How Ozone Is Formed

Ozone formation follows two distinct pathways—one natural and beneficial, one pollution-driven and harmful. Businesses managing air quality under ISO 14001 environmental management systems must understand both mechanisms to develop effective emission reduction strategies.

Natural Formation (Stratospheric)

Stratospheric ozone forms through a continuous natural cycle. Ultraviolet radiation from the sun strikes oxygen molecules (O₂) in the upper atmosphere, splitting them into individual oxygen atoms. These free oxygen atoms immediately collide with intact oxygen molecules, combining to form ozone (O₃). The process operates continuously, maintaining ozone layer density despite natural breakdown from UV exposure. A third molecule (usually nitrogen or oxygen) absorbs excess energy during formation, stabilizing the new ozone molecule.

Natural Ozone Formation Steps:

1. UV radiation (wavelength <242 nm) splits O₂ into two oxygen atoms
2. Free oxygen atom (O) collides with intact O₂ molecule
3. Third molecule (M) absorbs energy, allowing O + O₂ → O₃
4. Ozone absorbs UV-B radiation (280-315 nm), protecting surface ecosystems

Pollution-Driven Formation (Ground-Level)

Ground-level ozone forms when nitrogen oxides meet volatile organic compounds in sunlight. Internal combustion engines, thermal power plants, and industrial furnaces emit nitrogen dioxide (NO₂). Petroleum refineries, chemical manufacturing facilities, and vehicle fuel evaporation release VOCs including benzene, toluene, and formaldehyde. Solar radiation triggers photochemical reactions between these precursors, generating ozone molecules at ground level. Peak ozone formation occurs during hot, sunny afternoons when precursor concentrations and solar intensity both reach maximum levels.

Pollution Ozone Formation Steps:

1. NOx emissions (from vehicles, industry) + VOC emissions (from solvents, fuels)
2. Sunlight provides energy for photochemical reaction
3. NO₂ + VOCs + UV light → O₃ + other oxidants
4. Ozone accumulates near surface, creating urban smog

Also read: Components of Environment – A Complete Guide

How Ozone Protects Ecosystems

Stratospheric ozone is essential for life on Earth. It blocks 97–99% of harmful UV-B radiation and prevents DNA damage in plants, animals, and microbes. Without it, UV rays would penetrate leaves, destroy chlorophyll, and reduce photosynthesis. Crop yields for staples like rice, wheat, and pulses would sharply decline.

Ozone protection is equally critical for oceans. Phytoplankton—the base of marine food webs – live near the surface and perform most of the planet’s photosynthesis. High UV exposure kills these organisms, disrupts nutrient cycles, and reduces fish populations. The ozone layer filters UV-B before it reaches surface waters.

Ozone also supports climate stability. By absorbing solar energy, it warms the stratosphere and helps drive global air circulation. These circulation patterns regulate heat and moisture distribution. When ozone declines, circulation shifts and can disturb climate systems, including monsoon patterns vital for agriculture.

Without Stratospheric Ozone Protection:

• Crop yields would decline 20-30% from UV damage to leaf tissues
• Phytoplankton populations would collapse, eliminating ocean food chains
• Human skin cancer and cataract rates would increase exponentially
• Terrestrial ecosystems would shift toward UV-resistant species only

Harmful Effects of Ground-Level Ozone on Ecosystems

Ground-level ozone causes direct chemical damage to living systems. Unlike protective stratospheric ozone, it comes into contact with leaves, lungs, and soil microbes. Its high reactivity oxidizes cells and disrupts core biological functions.

Plants

• Enters leaves through stomata during gas exchange
• Damages cell membranes and chloroplasts → lowers photosynthesis
• Visible injury: brown spots, yellowing, bronzing
• Slows growth and reduces crop yields
• Typical yield losses under high ozone exposure:
  • Wheat: ~10–15%
  • Pulses (chickpea, pigeon pea): ~15–20%
  • Rice near industrial zones: poorer grain filling
• Forest trees show slower growth and weaker disease resistance
• Long-term exposure shifts forests toward less valuable, ozone-tolerant species

Animals

• Irritates and inflames respiratory tissues
• Reduces lung efficiency and stamina
• Weakens immunity → higher infection risk
• Plant damage lowers food quality and availability
• Food-web effects: herbivores decline → predators decline → ecosystem stability drops

Soil & Microbes

• Suppresses soil bacteria and fungi activity
• Slows decomposition and nutrient release
• Causes plant nutrient deficiencies despite organic matter presence
• Reduces mycorrhizal fungi that support root nutrient uptake
• Weakens drought resistance and ecosystem recovery capacity

Ozone and Aquatic Ecosystems

Ground-level ozone harms aquatic ecosystems indirectly. Ozone damages nearby vegetation and forests, reducing organic matter and habitat stability around rivers and lakes. This increases soil erosion and pollutant runoff into water bodies. Ozone also stresses aquatic plants and algae, lowering productivity and disrupting food chains. The result is reduced biodiversity and weaker ecosystem resilience.

Fish larvae show extreme sensitivity to UV radiation during early development. Transparent larval tissues offer minimal UV protection, allowing radiation to damage developing organs, nervous systems, and immune structures. Mortality rates increase 20-40% in surface-dwelling larvae when stratospheric ozone depletion permits elevated UV penetration. Species including sardines, anchovies, and herring—critical to Indian coastal fisheries—face recruitment failures when larval survival drops.

Coral reefs experience compounding stress from ozone-related factors. UV radiation damages zooxanthellae—symbiotic algae living inside coral tissues that provide nutrients through photosynthesis. Loss of zooxanthellae causes coral bleaching, weakening reef structures and reducing biodiversity. When combined with ocean warming and pollution, UV stress from ozone depletion accelerates reef degradation across Indian Ocean ecosystems.

Ozone Depletion and Ecosystem Risk

Ozone depletion describes the thinning of stratospheric ozone concentration, particularly over polar regions. Chlorofluorocarbons (CFCs) from refrigerants, aerosol propellants, and industrial solvents release chlorine atoms when exposed to stratospheric UV radiation. A single chlorine atom destroys thousands of ozone molecules through catalytic reactions before deactivation. Halons from fire suppression systems and methyl bromide from agricultural fumigation contribute similar destruction through bromine atom release.

The Antarctic ozone hole demonstrates the severity of chemical-induced depletion. Discovered in 1985, this seasonal thinning reduces stratospheric ozone by 50-70% each austral spring (September-November), exposing Southern Hemisphere ecosystems to dangerous UV levels. Arctic ozone shows similar but less severe thinning. Mid-latitude regions including India experience 5-10% ozone reduction, measurably increasing surface UV radiation.

Timeline of Ozone Depletion Response:

• 1974: Scientists identify CFC threat to ozone layer
• 1985: Antarctic ozone hole discovered through satellite monitoring
• 1987: Montreal Protocol treaty restricts ozone-depleting substances
• 1990s: CFC production phases down globally; halon alternatives deployed
• 2000s: Ozone depletion rate stabilizes; recovery signs emerge
• 2019: First evidence of Antarctic ozone hole healing (NASA/NOAA data)
• Projected 2060-2070: Full stratospheric ozone recovery if Montreal Protocol compliance continues

Ecosystem risks intensify during the recovery period. Even with CFC emissions eliminated, existing atmospheric concentrations persist for 50-100 years due to chemical stability. Ecosystems must adapt to elevated UV exposure throughout the recovery timeline. Species unable to develop UV resistance face population declines or extinction. Agricultural systems require UV-resistant crop varieties to maintain productivity. Indian coastal ecosystems show particular vulnerability given monsoon-dependent fisheries and high marine biodiversity.

Ozone and Climate Interaction

Ground-level ozone is a short-lived greenhouse gas that contributes to warming. Higher temperatures also speed up ozone formation, creating a feedback loop between heat and pollution. Climate change can increase ozone episodes through heatwaves and stagnant air conditions. This combined effect intensifies stress on crops, forests, and natural ecosystems.

Real-World Ecosystem Examples

Example 1: Agricultural Crops Under Ozone Stress (Indo-Gangetic Plain)

• Location: Punjab, Haryana, Uttar Pradesh agricultural zones
• Ozone Source: Vehicle emissions, crop residue burning, industrial facilities
• Peak Exposure Period: April-June (pre-monsoon)

Crop	Ozone Sensitivity	Yield Impact	Economic Effect
Wheat	High	10-15% loss at >40 ppb	₹8,000-12,000 crore annual loss
Rice	Moderate	5-10% loss at >50 ppb	Reduced grain quality
Chickpea	High	15-20% loss at >40 ppb	Protein supply reduction
Mustard	Moderate-High	8-12% loss at >45 ppb	Oilseed shortfall

Farmers in Punjab report visible leaf damage during peak ozone months. ESG Expertisse helps agricultural businesses implement air quality monitoring and adjust cultivation timing to minimize ozone exposure during critical growth stages.

Example 2: Forest Regions with Air Pollution (Western Ghats)

• Location: Karnataka, Kerala, Tamil Nadu forest reserves
• Ozone Source: Urban expansion, highway traffic, industrial corridors
• Impact Timeline: Chronic exposure over 15-20 years

Tree Species	Ozone Tolerance	Observed Effects	Ecosystem Consequence
Teak	Moderate	Growth rate reduction	Lower timber value
Rosewood	Low	Premature leaf drop	Regeneration failure
Sandalwood	Low	Increased disease susceptibility	Population decline
Sal	Moderate	Reduced seed production	Forest composition shift

Protected areas near industrial zones show measurable forest health decline. Businesses operating near forest ecosystems use ESG risk assessments to quantify pollution impacts and implement emission controls under Forest (Conservation) Act requirements.

Example 3: Coastal Plankton UV Exposure (Tamil Nadu Coast)

• Location: Gulf of Mannar, Palk Bay marine ecosystems
• Stressor: Stratospheric ozone depletion + local pollution
• Monitoring Period: February-May (peak UV intensity)

Organism Group	UV Sensitivity	Population Response	Fishery Impact
Diatoms (phytoplankton)	High	15-25% productivity loss	Reduced fish larvae food
Copepods (zooplankton)	Moderate	Behavioral changes	Disrupted food web
Fish larvae (sardine, anchovy)	High	20-30% mortality increase	Recruitment failure
Coral zooxanthellae	High	Bleaching acceleration	Reef degradation

Coastal communities dependent on small-scale fisheries face income volatility as fish stocks fluctuate. ESG Expertisse supports marine-dependent businesses with climate adaptation strategies and sustainable sourcing protocols aligned with Marine Products Export Development Authority (MPEDA) guidelines.

How Ecosystem Damage from Ozone Can Be Reduced

Businesses reduce ozone-related ecosystem damage through emission controls, operational changes, and strategic ESG integration. The Ministry of Environment, Forest and Climate Change (MoEFF&CC) mandates industry-specific emission limits under the Air (Prevention and Control of Pollution) Act, 1981. Companies meeting these standards protect ecosystems while achieving regulatory compliance.

Emission Reduction Strategies:

• Nitrogen Oxide Controls: Install selective catalytic reduction (SCR) systems on industrial boilers, furnaces, and diesel generators. SCR technology reduces NOx emissions by 80-90%, limiting ozone precursor release. Thermal power plants, cement kilns, and chemical manufacturing facilities achieve compliance with Central Pollution Control Board emission standards through SCR deployment.
• Volatile Organic Compound Management: Implement closed-loop systems in chemical processing, petroleum refining, and paint manufacturing. VOC recovery units capture solvent vapors before atmospheric release, reducing ozone formation potential by 70-85%. Companies selling recovered VOCs offset implementation costs while protecting air quality.
• Cleaner Transport Solutions: Transition vehicle fleets to Bharat Stage VI (BS-VI) emission standards or cleaner alternatives. Electric vehicles eliminate tailpipe NOx and VOC emissions entirely. Businesses operating logistics, distribution, or employee transport fleets reduce ozone formation while lowering fuel costs and carbon footprints.
• Industrial Process Controls: Optimize combustion efficiency in manufacturing operations. Well-tuned burners, boilers, and engines produce 30-40% less NOx than poorly maintained equipment. Preventive maintenance programs reduce emissions while improving energy efficiency and equipment longevity.

Air Quality Monitoring:

Deploy continuous emission monitoring systems (CEMS) at major emission points. Real-time NOx and VOC data enables immediate operational adjustments when pollution spikes occur. Companies demonstrate regulatory compliance and identify optimization opportunities through systematic monitoring. ESG Expertisse implements CEMS programs aligned with ISO 14001 environmental management systems and SEBI BRSR reporting requirements.

Install ambient air quality sensors around facility perimeters. Ground-level ozone monitors track local pollution impacts, providing early warning of air quality standard violations. Businesses use monitoring data to validate emission controls and communicate environmental performance to stakeholders.

Policy & Regulation Alignment:

Meet National Ambient Air Quality Standards (NAAQS) for ozone (100 µg/m³ 8-hour average). State Pollution Control Boards enforce these standards through inspection, testing, and consent-to-operate conditions. Companies exceeding limits face operational restrictions, financial penalties, and reputational damage.

Comply with Environment (Protection) Act emission limits specific to industry sectors. Automobile manufacturers, thermal power plants, petroleum refineries, and chemical facilities operate under customized NOx and VOC ceilings. ESG Expertisse conducts compliance audits and develops corrective action plans when violations occur.

Sustainable Practices Integration:

Adopt renewable energy sources to displace fossil fuel combustion. Solar photovoltaic systems, wind power, and biomass facilities eliminate combustion-related NOx emissions. Businesses achieve emission reductions while accessing renewable energy subsidies and carbon credits under India’s carbon market mechanisms.

Implement green chemistry principles in manufacturing processes. Substitute high-VOC solvents with water-based or low-emission alternatives. Chemical formulators reduce ozone formation potential while improving worker safety and product sustainability.

Design supply chains to minimize transportation emissions. Localized sourcing, route optimization, and shipment consolidation reduce vehicle kilometers traveled. Logistics companies cut fuel costs 15-25% while lowering NOx and VOC emissions through strategic network design.

FAQs – What Is Ozone and How Does It Affect Any Ecosystem?