Environmental Triggers

Airborne pollutants and allergens are exceptionally prominent triggers as people on average spend about ninety percent of their lives indoors. Potential exacerbating influences in the progression of asthmatic condition include airway irritants such as common house dust, bedding dust mites, evaporation of chemical pollutants, cooking fumes, and volatile organic compounds (Canadian Centre for Occupational Health and Safety, 2008). Inferior levels of indoor air pollutants have been known to be linked to respiratory ailments.  Inadequate ventilation allows build-ups of harmful gasses and particulates in the indoor environment that could cause further irritation.

Effect of Airborne Particulate Matter

Through my previous research, it was demonstrated that the airborne particulate level in a non-sustainable home is higher than that in a sustainable home (Graph 1). 

Graph 1: Air Particulate Count - Sustainable vs. Non Sustainable Home. EPA and Air Advice are recommended acceptable levels.

Effect of Carbon Monoxide and Carbon Dioxide

CO is harmful as it decreases oxygen levels and subsequently initiates cardiac and micro-vascular functions. According to an environmental study, “…for every 1ppm increase in the CO level, asthma symptoms increased by approximately 61% (Yu, n.d.).

 Graph 2: CO Concentration Level - Sustainable vs. Non Sustainable Home 

It was demonstrated that the CO and CO2 level in a non-sustainable home is relatively inferior (Graphs 2 and 3). 

Graph 3: CO2 Concentration Level - Sustainable vs. Non Sustainable Home

Effect of Total Volatile Organic Compounds (TVOCs)

TVOCs include chemicals that evaporate at room temperature.

Graph 4: TVOC Concentration Level - Sustainable vs. Non Sustainable Home

Lung Function and Pathophysiological Immune Response

Exposure to air pollutants results in a cascading allergic physiological response:

  • Mast-cells secrete substances including cytokines, histamine and heparin into blood stream in response to irritation from an asthma trigger. Release of these substances cause inflammation of lining in the bronchial tubes.
  •  Mucus is generated as the body’s response to irritants and subsequently narrow the lumin of the airways.
  • Bronchoconstriction, the phenomenon where the bands of muscle around the airways tighten up in response to the irritants, further narrowing the passage.

Antibodies, or immunoglobulins (IgE), help fight off such foreign substances called antigens which stimulate the body to produce more antibodies that attach themselves to the antigen in order to inactivate it (Havens, L., 2006).

The Peak Expiratory Flow (PEF) rate, measured in l/min, is the standard gage used to judge airway reactivity in asthmatic subjects as it serves as a direct indication of the level of constriction of the bronchial tubes (Mitchem, T., 2009).

Normalized PEF Rate

Medical practitioners utilize models based on Nunn's 1989 model (Equations 1 and 2) as a benchmark to compare the adult subject's PEF rate to. Any degradation in a subject's PEF from Nunn's model is typically attributed to pathophysiological factors. Note that Nunn's model is only a function of the subject’s age, height, and gender, and fails to quantify the effect of air pollutants.

Is Nunn's model an overestimate of the normalized PEF rate, and consequently are remediation efforts untargeted?


Figure out what others have found out about your subject area or question. How has your research helped you to refine your question and ask something that may not be unique, but is relevant and interesting and not already answered.


Judges' Tip
Excellent students will undertake research to help them shape their question and hypothesis and to put their work into a relevant, real-world context (500 words maximum).