Introduction: Air pollution and indoor air quality have become major concerns, affecting respiratory health and overall well-being. Many commercial air purifiers are expensive, making clean air inaccessible to many households. This DIY project aims to design and build a low-cost HEPA filtration air purifier using readily available materials. The project provides an affordable solution to reduce airborne pollutants, allergens, and dust, improving indoor air quality effectively.

Abstract: This project focuses on constructing a low-cost HEPA filtration air purifier using a simple box fan, a HEPA filter, and a wooden or plastic casing. The air purifier effectively captures dust, pollen, smoke, and fine particles, making it ideal for individuals suffering from allergies or respiratory conditions. By leveraging a fan-based air circulation system and HEPA filtration, the DIY purifier provides a cost-effective alternative to commercial air purifiers. The results show a significant reduction in indoor air pollutants, improving air quality in enclosed spaces.

Statement of the Problem: Poor indoor air quality contributes to respiratory issues, allergies, and overall discomfort. Many households cannot afford expensive commercial air purifiers, leaving them vulnerable to pollutants. Additionally, conventional air purifiers require frequent and costly filter replacements. This project addresses these challenges by developing an affordable, efficient, and easy-to-maintain HEPA filtration air purifier.

Apparatus:

• Box fan (standard 20-inch household fan)
• HEPA filter (compatible with the fan size)
• Wooden or plastic casing (optional, for enclosing the system)
• Activated carbon filter (optional, for odor removal)
• Tape or zip ties (for securing the filter)
• Air quality sensor (for monitoring effectiveness)
• Power supply (standard AC outlet)
• Screwdriver and basic tools

Procedure:

1. Prepare the Box Fan:
   • Clean the fan blades and outer casing to remove any dust.
   • Ensure the fan operates smoothly without any mechanical issues.
2. Attach the HEPA Filter:
   • Secure the HEPA filter to the air intake side of the fan using tape or zip ties.
   • Ensure an airtight seal to prevent unfiltered air from bypassing the filter.
3. Enhance Filtration with an Activated Carbon Layer (Optional):
   • Place an activated carbon filter in front of the HEPA filter to remove odors and gases.
   • Secure it properly to maintain efficient airflow.
4. Build a Casing (Optional):
   • Construct a wooden or plastic frame around the fan and filter assembly for added durability.
   • Ensure proper ventilation for air circulation.
5. Test the Airflow:
   • Turn on the fan and check airflow direction.
   • Ensure the filter captures dust and fine particles effectively.
6. Monitor Air Quality (Optional):
   • Use an air quality sensor to measure changes in indoor air quality before and after operation.
   • Adjust the setup if needed for optimal performance.

Results: After running the air purifier for several hours, the indoor air quality improved significantly. The HEPA filter effectively trapped fine dust, pollen, and airborne particles, visibly reducing pollutants in the air. The optional activated carbon filter further enhanced air freshness by removing odors and volatile organic compounds (VOCs).

Observation:

• The air purifier operated efficiently with minimal noise.
• The HEPA filter accumulated visible dust and particles over time, proving its effectiveness.
• The use of an air quality sensor indicated a measurable reduction in airborne contaminants.
• The setup required minimal maintenance apart from periodic filter cleaning or replacement.

Variables:

• Independent Variable: Type of HEPA filter and fan speed.
• Dependent Variable: Air quality improvement (measured by particle reduction).
• Controlled Variables: Room size, duration of operation, and ambient air conditions.

Conclusion: The DIY HEPA filtration air purifier provides an effective and affordable solution for improving indoor air quality. The use of a standard box fan and HEPA filter ensures efficient removal of airborne particles, making it a viable alternative to commercial air purifiers. The project demonstrates that with simple modifications, households can create a cost-efficient air purification system.

Recommendation:

• Use a higher-grade HEPA filter for enhanced filtration efficiency.
• Replace the filter periodically to maintain optimal performance.
• Integrate a real-time air quality monitor for automated control.
• Improve the casing design for enhanced durability and aesthetics.
• Test the purifier in different environments to determine its effectiveness across various conditions.