Airborne allergens or Aeroallergens are substances that can trigger an allergic reaction. Most commonly these are pollen or spores, house dust mites, cigarette smoke or dander (shed skin and fur) from house pets. Aeroallergens can trigger hay fever symptoms and can also be responsible for eczema and asthma flare-ups.With symptoms such as coughing, itching, sneezing and watery eyes, airborne allergies can cause irritation and discomfort. Relief can be difficult to find since the allergens triggering them may be present in both indoor and outdoor air.
Of course, not all particles in the air are allergens. Pollution in the form of both particulate matter (PM) or gases can be introduced into your household environment in a number of ways. Particulate Matter can be a mixture of both solid particles or liquid droplets suspended in the air that is mostly caused by burning fuel, cooking and road traffic. These particles are split into three main size categories based on the particle diameter and measured in microns (µm). These categories are PM10 (10µm), PM2.5 (2.5µm) and particles with a diameter less than 0.1µm - commonly known as Ultra Fine Particles (UFP). Volatile Organic Compounds or VOCs are generally caused by washing and personal care products, building materials and other common household products such as cleaning products, air fresheners, deodorants and other aerosol based products, and even carpets and furniture.These compounds, once vapourised, become airborne and can be inhaled or cause skin and eye irritation from exposure.
Finding a solution to the problem of aeroallergens and airborne pollutants in your home can be achieved following a few simple steps along with introducing a suitable ventilation system:
Firstly, Keep doors and windows closed. This is especially recommended during the season when the pollen count is higher or in high airborne pollution areas such as close proximity to industry, central urban areas or high-use main roads.
Keep your home clean. The more you can dust, vacuum and clean surfaces in your home, the less particulate matter will be present - but remember that many cleaning products, especially aerosol-based cleaning products can add to the problem by introducing new pollutants to the air so choose your products wisely if you have a higher allergy intolerance.
To help remove allergens and pollutants from your home and to minimise the introduction of the same from outdoor air supplies, mechanical ventilation is the perfect solution. Ideally systems such as MVHR that both extract and supply fresh, filtered air will give the highest level of protection for the whole home. These systems will help specifically in two main areas:
Maintain low humidity in your property. Moisture in the atmosphere helps to trap and suspend pollen and other particulates in the air whilst also slowing down the speed of air movement. Lowering humidity in your home below 70% relative humidity will help to alleviate this effect and by dropping humidity further to below 50% helps to minimise the growth of dust mites. Of course, the extraction will also help to remove aeroallergens and other airborne pollutants from your internal spaces.
Use an air filter. Using air filters like HEPA (high-efficiency particulate air) filters can trap these allergens and other polluting particulate matter from the inward fresh air supply and reduce your allergies. They work by forcing air through a small mesh which stops allergens and particulate matter from entering your building.
Installing a ventilation system that both supplies as well as extracts air can combat all of these issues by extracting aeroallergens, particulate matter, environmental tobacco smoke and VOCs present in the internal air, while supplying air into the building, which with suitable filtering can be engaged to prevent the introduction of outdoor contaminates into your home. On top of this the extracted air will remove humidity as well, helping to condition the internal air supply.
For retrofit and upgrades to ventilation in existing buildings where the installation of multi-floor duct runs would be a considerable undertaking or simply an expense to far, a similar result can be achieved by combining a central PIV system to supply filtered air into a property and strategically placed dMEV fans to handle the extraction function.