My apologies, but I’m not capable of generating a response that contains 15,000 words due to technical limitations. However, I can help create a detailed outline that you might expand yourself or in subsequent requests with me.

Title: Boosting Indoor Air Quality with Houseplants

1. The Link between Indoor Air Quality and Health
a. Understanding the importance of indoor air quality
b. Health risks associated with poor indoor air quality
c. The need for natural solutions

2. The Science of Houseplants Improving Air Quality
a. Detailing NASA’s Clean Air Study
b. How houseplants purify air: the process of phytoremediation
c. Other ways plants improve indoor air: Humidity regulation, CO2 absorption

3. Popular Houseplants for Air Purification
a. Areca Palm: Growth, care, and air purification properties
b. Snake Plant: Maintenance, benefits, and selection guide
c. Spider Plant: Ideal environment & its high-quality purification effects
…[repeat the point for numerous plants]

4. Caring for Houseplants: Ensuring Their Survival and Function
a. Proper watering, light, temperature, and feeding for houseplants
b. Dealing with common houseplant pests and diseases
c. Re-potting and propagation tips

5. Placement of Houseplants for Optimal Air Quality Enhancement
a. Best locations for houseplants
b. Balancing aesthetic and functional placement
c. Considerations for households with pets and children

6. Enhancing Air Quality Through Smart Houseplant Selection
a. Choosing plants based on specific needs (Allergies, pets, space)
b. Combining different plants for comprehensive air purification

7. Expanding Indoor Air Quality Efforts Beyond Houseplants
a. Importance of regular cleaning and maintenance
b. Balancing natural ventilation with energy efficiency
c. Using natural air fresheners in conjunction with houseplants

Remember, SEO-optimized content requires the use of relevant keywords, internal and external links, and engaging meta descriptions. The use of subheadings, bullet points, and short paragraphs can greatly improve readability. In-depth research is crucial for creating high-quality content, so remember to verify all facts and attribute all information correctly. Make the content engaging by telling stories, asking questions, and using an active voice. Don’t forget about the importance of proofreading – your content needs to be free of grammatical errors and awkward phrasing.

Apologies again for the inability to write the full 15000-word article.