Activated Carbon Solutions for Cold Storage: Ethylene Control, Odor Removal and VOC Filtration

Why Air Quality Matters in Cold Storage

Temperature and humidity are usually the priorities in cold storage management. Refrigeration systems, insulation performance, and humidity control receive significant attention because they directly affect product preservation.

Yet product deterioration still occurs in many facilities, even when environmental conditions remain within specification.

Fruit may ripen ahead of schedule. Seafood can develop persistent odors. Meat products may lose quality during extended storage. Sensitive pharmaceutical products can become exposed to airborne contaminants.

The missing factor is often air quality.

Cold storage environments are not completely inactive. Fruits and vegetables continue to respire after harvest. Meat and seafood release various decomposition by-products. Packaging materials, cleaning agents, and nearby production processes can introduce volatile organic compounds (VOCs) into the storage atmosphere.

Over time, these contaminants accumulate inside enclosed storage rooms, air handling systems, and recirculating ventilation loops.

In many cold-chain operations, air quality becomes the hidden factor limiting storage performance after temperature and humidity have already been optimized.

For this reason, modern cold storage facilities increasingly incorporate gas-phase filtration systems to manage airborne contaminants and maintain product quality throughout the storage cycle.

Among available filtration technologies, activated carbon remains one of the most widely adopted solutions for controlling odors, VOCs, ethylene, sulfur compounds, and other unwanted gases.

Common Air Contaminants in Cold Storage Environments

Different products generate different airborne contaminants during storage.

The composition and concentration of contaminants vary significantly depending on product type, storage duration, airflow design, and loading density.

Ethylene Management in Fruit and Vegetable Storage

Ethylene is one of the most important gases in fresh produce storage.

Produced naturally by fruits and vegetables, ethylene acts as a plant hormone that regulates ripening. Apples, bananas, pears, avocados, tomatoes, mangoes, and kiwifruit continuously release ethylene throughout storage.

Even low concentrations can influence nearby produce.

In commercial cold storage facilities, ethylene accumulation may result in:

• Faster ripening
• Reduced storage life
• Uneven product quality
• Increased waste
• Higher transportation losses

Many controlled-atmosphere (CA) storage facilities monitor ethylene levels as part of their storage management program.

An apple warehouse designed for six to ten months of storage may experience quality losses when ethylene concentrations exceed approximately 1 ppm for extended periods.

To address this issue, activated carbon filtration is frequently installed within recirculating air systems, ripening rooms, and fresh produce distribution centers.

Real-World Example: Ethylene Control in Produce Storage

A fruit distribution center storing apples, pears, and kiwifruit experienced inconsistent ripening during long-term storage.

Temperature and humidity remained within target ranges, yet product losses continued to rise.

Air-quality monitoring identified elevated ethylene concentrations in several storage chambers.

After integrating activated carbon filtration into the recirculating airflow system, ethylene accumulation was reduced, and product consistency improved throughout the storage cycle.

For facilities handling fresh produce, ethylene control often delivers greater storage benefits than further adjustments to refrigeration settings alone.

Odor Control in Meat and Seafood Cold Rooms

Odor management remains a major challenge in meat processing plants, seafood storage facilities, and refrigerated distribution centers.

During storage, proteins naturally break down and release odor-causing gases.

Common contaminants include:

• Ammonia (NH₃)
• Hydrogen sulfide (H₂S)
• Trimethylamine (TMA)
• Sulfur-containing organic compounds

Although refrigeration slows these reactions, it does not stop them completely.

Seafood facilities often encounter trimethylamine buildup. Operators frequently describe the problem as odor breakthrough, particularly in enclosed cold rooms with limited air exchange.

Meat storage facilities face similar challenges when ammonia and sulfur compounds accumulate within storage zones.

Potential consequences include:

• Strong odors
• Reduced perceived freshness
• Worker discomfort
• Cross-contamination between storage areas
• Customer complaints

Activated carbon systems are commonly installed upstream of return-air ducts and HVAC circulation systems to reduce odor migration and maintain a cleaner storage environment.

VOC Control in Dairy and Pharmaceutical Storage

Volatile organic compounds can originate from numerous sources inside cold storage facilities.

Typical sources include:

• Packaging materials
• Cleaning chemicals
• Plastic containers
• Adjacent manufacturing areas
• Industrial solvents

In dairy storage environments, VOC contamination may affect flavor, aroma, and product consistency.

Pharmaceutical storage facilities often impose even stricter air-quality requirements.

Facilities operating under GMP guidelines frequently incorporate gas-phase filtration systems as part of their environmental control strategy.

Trace levels of chemical vapors can potentially affect product stability, making VOC control a critical component of long-term storage management.

Activated carbon filtration provides an effective method for reducing airborne VOC concentrations without introducing additional chemicals into the storage environment.

Flowchart of the activated carbon ethylene removal working principle, showing the low-temperature adsorption phase and high-temperature desorption regeneration phase in a twin-tower alternating cycle.

How Activated Carbon Removes Cold Storage Contaminants

Activated carbon contains a highly porous structure with millions of microscopic pores.

A single gram of premium activated carbon may provide more than 1,000 m² of internal surface area.

As contaminated air passes through the carbon bed, gas molecules are captured within the pore network.

Several mechanisms contribute to contaminant removal.

Physical Adsorption

Physical adsorption is the primary removal mechanism for many contaminants found in cold storage environments.

Micropores smaller than 2 nanometers are particularly effective for capturing:

• Ethylene
• VOCs
• Organic vapors
• Odor compounds

Coconut shell activated carbon is often chosen for its highly developed microporous structure and strong adsorption capacity for low-molecular-weight gases.

Chemical Adsorption

Certain contaminants are difficult to remove through physical adsorption alone.

Impregnated activated carbons are therefore used for gases such as:

• Hydrogen sulfide
• Sulfur compounds
• Acid gases
• Corrosive vapors

These products may contain:

• Potassium iodide (KI)
• Potassium hydroxide (KOH)
• Copper compounds
• Proprietary catalytic additives

Chemical reactions occurring on the carbon surface convert contaminants into more stable compounds.

Catalytic Oxidation

Some activated carbon products also function as catalytic media.

Instead of merely trapping contaminants, they promote oxidation reactions that convert gases into less harmful substances.

Catalytically activated carbon is increasingly used for ethylene management in large-scale produce storage and cold-chain logistics applications.

Choosing the Right Activated Carbon for Different Storage Applications

Carbon selection should be based on contaminant type, airflow volume, residence time, humidity levels, and replacement interval targets.

Selecting the correct carbon media often has a greater impact on filtration performance than simply increasing carbon volume.

Typical Installation Locations in Cold Storage Facilities

Activated carbon systems can be integrated into multiple areas of a cold storage operation.

Common installation points include:

HVAC Air Handling Units

Continuous treatment of recirculated air throughout the facility.

Return-Air Duct Systems

Reduction of contaminant buildup before air re-enters storage chambers.

Ripening Rooms

Control of ethylene concentrations during fruit storage and conditioning.

Odor-Control Units

Removal of sulfur compounds and organic odors generated by stored products.

Packaging and Processing Areas

Protection against VOCs and airborne contaminants before products enter storage.

Proper placement improves filtration efficiency and helps maximize carbon service life.

Benefits of Activated Carbon in Cold Storage Operations

Activated carbon offers several operational advantages for cold storage operators.

Key benefits include:

• Lower product shrinkage
• Reduced odor complaints
• Extended storage cycles
• Improved inventory consistency
• Better cold-chain performance
• Compatibility with existing HVAC infrastructure
• Low operating costs
• No chemical spraying inside storage rooms

The technology can be applied to both small refrigerated warehouses and large industrial cold-chain facilities.

Future Trends in Cold Storage Air Quality Management

Growing international trade is extending storage and transportation times across global supply chains.

Longer storage cycles increase the importance of controlling airborne contaminants.

Several trends are driving demand for advanced air-quality management systems:

• Expansion of global cold-chain logistics
• Increased use of controlled-atmosphere storage
• Wider adoption of ethylene monitoring systems
• Integration of HVAC filtration technologies
• Food waste reduction initiatives
• Higher pharmaceutical storage standards
• ESG-focused operational strategies

As storage periods become longer and product quality requirements become stricter, air-quality management is expected to play a larger role in cold storage design and operation.

Activated carbon will remain a key technology for controlling odors, VOCs, ethylene, sulfur compounds, and other airborne contaminants across modern cold-chain facilities.