Poor indoor air quality (IAQ) in commercial buildings is typically due to a mix of combustion gases, particles, vapours, and bioaerosols. The result is preventable complaints, productivity loss, and, at higher exposures, acute or chronic health effects.
Below are the priority indoor air contaminants we see across offices, retail spaces, healthcare facilities, and education centres, including exposure mechanics, health risks, and the approach Nichols Environmental + Engineering uses to diagnose issues.
Combustion Gases: Carbon Monoxide (CO) And Nitrogen Dioxide (NO₂)
Sources: Boilers, unit heaters, furnaces, appliances, vehicle infiltration from parkades/loading bays, and short-circuited flues.
Health risks: CO interferes with oxygen transport and can cause headaches, dizziness, and, at higher concentrations, life-threatening toxicity. NO₂ irritates airways and exacerbates asthma; gas appliances without effective capture ventilation are common contributors.
Health Canada maintains residential IAQ guidelines for both gases used operationally in public/commercial settings to benchmark risk and trigger corrective actions.
Fine Particulate Matter (PM₂.₅)
Sources: Outdoor air ingress, combustion processes, renovation activities, and resuspended dust.
Health risks: PM₂.₅ penetrates deep into the lungs and is associated with cardiovascular and respiratory morbidity. Indoor concentrations often track outdoor events unless filtration and pressurization are effective.
Health Canada provides IAQ guidance for multiple substances that fall in this category.
Volatile Organic Compounds (VOCs) And Formaldehyde
Sources: Composite wood, adhesives, sealants, paints, floor finishes, new furnishings, and maintenance products.
Health risks: Eye, nose, and throat irritation; headaches; in sensitive occupants, worsening of asthma symptoms.
Canada regulates formaldehyde emissions from composite wood products under CEPA, reducing a major source in new fit-outs. Post-renovation flush-outs and material vetting remain essential.
Radon
Sources: Soil gas intrusion through slab and foundation penetrations, particularly in ground-contact and low-level spaces.
Health risks: Long-term exposure increases lung cancer risk.
Canada’s guideline is 200 Bq/m³ (annual average); mitigation is recommended at or above this level. Long-term (≥91-day) testing supports decisions.
Mould
Sources: Building envelope leaks, plumbing failures, wet slabs, HVAC condensate management, and relative humidity excursions.
Health risks: Upper-airway irritation, asthma symptom triggers, and allergenic responses.
The public-health position is direct. Fix moisture, remove damaged materials, and clean. There are no agreed-upon “safe” mould levels (though some species are more harmful than others).
How Nichols Assesses IAQ And Remedies Root Causes
Air quality issues often prompt our building assessments. Here’s an overview of how we tackle the problem.
Scoping And History
We start with complaint patterns, occupancy, and operations. We review HVAC design intent versus current operation (outside-air rates, filtration, pressurization, exhaust interaction, setback strategies).
Field Measurements
We deploy calibrated monitors for indicator parameters (temperature, RH, CO, CO₂) and targeted contaminants where indicated: direct-reading CO/NO₂; integrated VOC/formaldehyde sampling; particles (gravimetric/optical for PM₂.₅); and mould indicators tied to moisture mapping. For radon, we implement long-term devices in representative zones.
Source And Pathway Diagnostics
We test garage/building interfaces, appliance venting, and return-air pathways; assess material emissions post-fit-out; and verify filtration (MERV ratings, pressure drops) and air distribution.
Reporting And Controls
Deliverables prioritize immediate controls (combustion safety, ventilation corrections, moisture repairs), then medium-term actions (material specifications, filtration upgrades, post-renovation flush-out), with verification sampling where appropriate. Our teams integrate IAQ findings with hazardous building materials and Occupational Hygiene programs so owners have a single, decision-ready plan.
Contact Our Building Experts Today
If you’re seeing recurring complaints, odours after renovations, or seasonal CO/NO₂ spikes near parking or loading, we can scope a targeted IAQ assessment that resolves the root cause and documents compliance against Canadian and provincial guidance.
Contact Nichols Environmental + Engineering today to get started.
