Why Allergies are Worse Indoors During Summer

Most people like being outside on a bright, sunny summer's day, but those who suffer from hay fever may find summertime unbearable due to pollen from grasses, trees, and flowers, which can cause unpleasant allergy symptoms including sore throats, streaming eyes, and blocked noses.

One of the most common allergies, hay fever is thought to afflict around 20% of the UK population. A straightforward daily antihistamine tablet can alleviate minor symptoms for many sufferers; but those with more severe cases may not be able to find any relief at all on days with high pollen counts, and even staying indoors with closed windows might not help prevent a reaction.

What causes hay fever?

Hay fever is a severe seasonal allergy caused by an immune system response to the inhalation of pollen grains released by plants. Hay fever varies from person to person. Some people might be allergic to a specific type of pollen while others might suffer with all pollens and have symptoms throughout the summer.

In the UK, the hay fever season runs from May through until September with peaks in June and July when grasses and other plants are most likely to flower and release their pollen into the air. 

Grass pollens are the biggest cause of hay fever simply because large fields can release their pollen at a similar time which means huge amounts of pollen in the air nearby. Hot and breezy days are the worst time for sufferers, as a light wind is more likely to carry the pollen into the face where it is inhaled or brought into contact with the eyes.

How pollen gets into your home

Pollen grains are microscopic – even the largest grain of pollen in the world is only slightly larger than the thickness of a human hair. Windborne pollens are typically between 15 and 35 microns in diameter (less than 1/30^th of a millimetre). The tiny size of pollen grains means that they can easily enter a house through any gaps around doors or windows, or even through the vents in your loft. Pollen can be carried into a building on people’s clothing or shoes, as well as in hair and on skin.

In the home, pollen grains become mixed in with other dust, but because they are so light, they can easily be picked up by airflow and inhaled.

Sufferers of hay fever should avoid taking the clothes they wear outdoors off in their bedroom and may also benefit from taking a shower before bed to remove any pollen from their hair and skin that would otherwise be transferred onto their pillow during the night.

Reducing how much pollen is in your home

Improving the ventilation in your home will help prevent a build-up of pollen, however it’s not possible to just open a window as that would allow more to enter.

Positive Input Ventilation Systems (PIV) are the most effective way of preventing the build-up of pollen in the home. Air is drawn in from outside the building through filters that remove particles. This air is gently dispersed through the building and carries allergens out as it escapes through ventilation gaps.

A PIV system creates a higher air pressure inside the building which also helps to prevent unfiltered air entering through other sources such as doors and windows.

Ventilation will not prevent pollen from entering the house on clothing or hair but will significantly reduce the amount of pollen that is present.

Find out More

If hay fever is stopping you enjoying your home during the summer, we can help. Contact us today to book your free home survey. Our local ventilation specialists can visit your home to provide you with advice about the best solution for your property. Simply enter your postcode in the form below to find a ventilation expert near you