Air Quality and Production
Air composition directly influences photosynthesis, transpiration, and overall plant vigor. Key factors include:
- Carbon Dioxide (CO₂): Elevated CO₂ up to 1 000-1 500 ppm speeds growth; below 400 ppm slows it [2].
- Humidity: 50-70 % RH optimizes stomatal function; extremes hinder nutrient uptake and can cause tip burn.
- Temperature: 20-28 °C promotes metabolic activity; heat stress (>30 °C) reduces yields.
- Particulate Matter (PM): Dust and spores clog stomata, lowering photosynthetic efficiency.
- Volatile Organic Compounds (VOCs): Off-gassing from building materials can stunt growth and alter flavor.
- Improving ventilation, using air filtration, and supplementing CO₂ can enhance yields; neglecting air exchange or sealing too tightly can concentrate pollutants and reduce plant quality.
Health Impacts of Poor Air Quality
Workers in sealed grow rooms may face elevated exposure to:
- High CO₂ levels: Above 5 000 ppm can cause headaches, dizziness, and fatigue.
- High humidity and mold: Promotes fungal spores, leading to allergic reactions and respiratory irritation.
- Particulates and VOCs: Linked to "sick building syndrome," with symptoms like eye irritation and headaches [1].
Mold Types and Health Impacts
Common indoor molds include the following types [5]:
- Stachybotrys chartarum (Black Mold) [6]
-- Respiratory irritation and chronic coughing
-- Severe allergic reactions and mucous membrane inflammation - Aspergillus species
-- Aspergillosis and lung infections in immunocompromised individuals
-- Allergic bronchopulmonary aspergillosis - Penicillium species
-- Allergic reactions and asthma exacerbation
-- Upper respiratory tract infections - Cladosporium species
-- Nasal congestion and sneezing
-- Skin rashes and eye irritation
Measurement Tools
- CO₂ meters: Infrared sensors for 0-5 000 ppm (cost $100-$500).
- Thermo-hygrometers: Digital probes for temperature (°C) and relative humidity (% RH).
- Particle counters: Laser-based monitors for PM₂.₅/PM₁₀ (µg/m³).
- VOC detectors: Photoionization detectors (ppb range).
- Airflow meters: Anemometers to verify ventilation rates (m³/h).
Optimal and Unhealthy Ranges
| Measurement (Unit) | Optimal for Plants | Unhealthy for Humans |
|---|---|---|
| CO₂ (ppm) | 1 000-1500 | >5 000 |
| Relative Humidity (% RH) | 50-70 | >70 (mold risk) |
| Temperature (°C) | 20-28 | > 30 (heat stress) |
| PM₂.₅ (µg/m³) | < 10 | > 35 (respiratory hazard) |
| VOCs (ppb) | < 500 | > 1 000 (irritation) |