Cejas Cooling & Construction

Between Breath and Burden

Between Breath and Burden: The Quiet War for Indoor Air Quality

Before you even taste your morning coffee, you’ve already inhaled thousands of molecules—some clean, some not. Indoor air, like ice machines or compressors, runs silent until something goes wrong. But when it does, it doesn’t just fail systems—it fails lungs, sleep cycles, immune responses. And it’s our job to catch it before the silence turns into sickness.

Why Indoor Air Quality Matters

Good indoor air quality (IAQ) isn’t a luxury—it’s survival in disguise. Poor IAQ has been linked to asthma, respiratory illness, fatigue, even cognitive decline. We’re indoor creatures now, spending over 90% of our time inside. The air in our homes is the air in our blood.

The Standard to Know

ASHRAE Standard 62.1 is the benchmark. It lays out ventilation requirements for acceptable IAQ in residential and commercial spaces. If you’re serious about clean air, this is the foundation.

Controlling Contaminants

IAQ control is a three-pronged strategy:

  • Source Control: Eliminate or seal off pollution sources
  • Ventilation: Bring in fresh air and exhaust stale, polluted air
  • Filtration & Purification: Remove particulates, gases, and biologicals from recirculated air

How Construction Affects IAQ

Tighter buildings mean energy savings—but also less natural ventilation. Sealing everything up without a ventilation strategy traps humidity, VOCs, carbon dioxide, and airborne particles. That cozy insulation? It’s a two-edged sword.

Five HVACR-Related Pollution Sources

  1. Dirty evaporator coils
  2. Moldy ductwork
  3. Combustion byproducts from gas furnaces
  4. Improper humidifier maintenance
  5. Leaky return ducts in crawlspaces or attics

Six Common Air Pollutants

  1. Particulate Matter (PM2.5 and PM10)
  2. Volatile Organic Compounds (VOCs)
  3. Carbon Monoxide (CO)
  4. Carbon Dioxide (CO2)
  5. Nitrogen Dioxide (NO2)
  6. Biologicals (mold, pollen, bacteria)

Sick Building Syndrome

A condition where occupants experience health issues—headaches, fatigue, eye irritation—without a specific illness diagnosed. Often caused by poor ventilation, off-gassing from materials, or hidden mold.

Mold Remediation

Critical. Mold spores can inflame lungs and worsen chronic respiratory issues. Clean the source, dry the area, and treat with EPA-approved disinfectants. It’s not just a stain—it’s a health threat.

Carbon Dioxide Formation

CO2 forms during combustion. It’s not toxic like CO, but elevated levels (above 1000 ppm) indicate poor ventilation and can cause drowsiness and poor concentration.

Common Pollutant Dangers

  • CO: Colorless, odorless, deadly. Blocks oxygen from binding in blood.
  • Asbestos: Fibrous and dangerous when airborne. Causes mesothelioma and lung disease. Removal requires certified professionals.

The Role of Ventilation

Ventilation is the bloodstream of indoor air quality. It dilutes pollutants, balances humidity, and reduces disease spread. Natural isn’t enough—controlled, mechanical ventilation is key.

Heat vs Energy Recovery Ventilators

  • HRV: Transfers heat from outgoing to incoming air
  • ERV: Transfers both heat and moisture

ERVs are better for humid climates, HRVs shine in colder ones.

MERV Ratings

Minimum Efficiency Reporting Value (MERV) rates filters from 1 to 20. The higher the number, the smaller the particles it can trap. Residential systems usually sit between MERV 8 and 13.

Six Types of Air Filters

  1. Fiberglass (throwaway)
  2. Pleated media
  3. Electrostatic filters
  4. HEPA filters
  5. Activated carbon filters
  6. Washable filters

Face-Loading Explained

As filters capture particles, they clog from the surface inward—this is face-loading. It increases resistance and reduces airflow if not replaced.

Electronic Air Cleaners

Four key parts:

  1. Pre-filter
  2. Ionization section
  3. Collection plates
  4. Power supply

They zap particulates mid-flight, charging them so they stick to oppositely charged plates.

Ion Generators and UV Lights

  • Ionizers: Electrically charge particles to clump together and settle out of the air
  • UV Lights: Kill microbes like mold and bacteria, often installed near coils or in ductwork

Absorption vs Adsorption

  • Absorption: Substance soaks into the material (like a sponge)
  • Adsorption: Substance clings to the surface (like a magnet). Carbon filters use adsorption to trap VOCs.

Air Distribution System Cleaning

Clean ducts = cleaner air. Dust, mold, and debris in the ductwork become airborne contaminants. It’s not always necessary, but in older homes, post-construction, or mold issues—it matters.

Relative Humidity and Comfort

Relative humidity (RH) is the amount of moisture in the air compared to how much it can hold. Ideal indoor RH is 30–50%. Too low? Dry skin, static, nosebleeds. Too high? Mold, dust mites, sticky discomfort.

Why Humidify in Winter?

Cold air holds less moisture. As it’s heated, it becomes desert-dry. Humidification prevents respiratory discomfort, protects wood floors and instruments, and supports immune defense.

Four Common Humidifier Types

  1. Evaporative (wick and fan)
  2. Steam (boils water into vapor)
  3. Ultrasonic (high-frequency vibration)
  4. Bypass (duct-mounted, passive airflow)

Sizing Humidifiers

Consider:

  • Square footage
  • Building envelope tightness
  • Ceiling height
  • Desired RH level
  • Indoor and outdoor design temps

Troubleshooting Filtration and Humidification

  • Clogged filters: Drop in airflow, increased pressure
  • Faulty humidistats: No operation or over-humidifying
  • Dry pads in bypass units: Caused by failed solenoids or clogged water lines
  • Water leaks: Trace back to drains or overflow lines

Indoor air is either the medicine or the poison. You don’t see it, but your body registers every molecule. And if you’re the tech on the call, your job is to make sure each breath someone takes in their home doesn’t sabotage their health. Because comfort isn’t just about temperature—it’s about trust in the invisible.