Why and how we certify in-car cabin filters – a Q&A

Why and how we certify in-car cabin filters – a Q&A

There is ever-increasing awareness of the chemicals and allergens we come into contact with every day, particularly if you or a member of your family has asthma or allergies. We created the asthma & allergy friendly® Certification Program to help you improve your indoor environment by identifying products and services that can help to reduce allergens and create a healthier home environment.

But what is it that makes some HVAC/furnace filters better for the indoor environment than others, and where do we draw the line to decide to certify a HVAC/furnace filter as asthma & allergy friendly® ? We hope that the questions below will clarify this. Let us know if you have more questions!

Car-Cabin-Indoor-Air-Allergy-StandardsWhy do we certify car cabin filters?

Our goal in the asthma & allergy friendly® Certification Program is to create a healthier indoor environment for you and your family, as well as to reduce allergens in the home. So we look at all elements of the indoor air environment.

It is easy to forget that the time you spend in your car counts as being indoors. In industrialised countries, people spend an average of one hour per day in a vehicle, and during this time you can be exposed to traffic-related pollutants as well as pollen from roadside trees and grasses. Certified cabin filters can help improve the air quality in the confined space of a vehicle cabin.

How do we test in-car cabin filters?

We use a standardised test duct to test these filters. This is a controlled duct where the filter can be inserted at the centre, and air can be forced through it. We can introduce dust containing allergens in the ‘upstream’ part of the duct. This air is then pressed through the filter, and we can test the ‘downstream’ area past the filter to see how much allergen and dust has passed through the filter.

1. Removal of Allergen and Dust

We introduce a specific amount of test dust that contains three common types of pollen, and a blower forces the dusty air through the filter. When the air passes through the filter, we test it on the other side to see how much of the dust and the allergen passed through. We require that at least 90% of each type of pollen is captured by the filter, and we also make sure that the filter has 85% efficiency in capturing all particles of greater than 3 micrometers.

2. Loaded Performance

It isn’t enough to only test a brand-new filter and check if it can remove allergens and small particles. Over time, dust can build up on a filter, which is why you need to change it every so often. But before that, it is important that even when it is loaded with dust the filter can still perform well. We challenge the filter with and record the filter flow and the air pressure in the test duct before and after the filter. We make sure that the performance of a loaded does not drop by more than 20% compared to a fresh filter.

3. Fiber Shedding

The purpose of a filter in your vehicle’s ventilation system is that it would capture small particles so that they are not available for you to breathe in. However, filters can themselves release tiny fibers that can irritate the respiratory system. We test the filters in the test duct and count any small fibers that are released to make sure they are at a suitably low level.

Why do we test with different pollens?

We use three common pollen types in our testing – timothy grass, birch tree, and ragweed. These pollens vary in terms of size, with ragweed being the smallest on average, and timothy grass being the largest. They are also prevalent at different times of the year, although pollen season does vary by region. But generally in the US, tree pollens (including birch) peak in Spring, grass pollens (including Timothy) peak in Summer/early Fall, and weed pollen (including ragweed) peaks in Fall.

Car-Cabin-Indoor-Air-Allergy-Standards2How often should you change your in-cabin filter?

You should always follow the manufacturer’s instructions for changing the filter. When a filter is certified asthma & allergy friendly®, we will have tested it when the filter is loaded with dust to make sure it retains most of its efficiency. But as more and more dust settled on the filter, the performance will inevitably start to drop.

What else do we certify?

We have 46 different asthma & allergy friendly® certification standards for products and services, addressing all areas of the indoor air environment. Some of these relate to products which remove allergens and dust from the indoor environment, like vacuum cleaners, air cleaners, dehumidifiers, and washing machines. Some of them relate to products where it is important not to provide an easy home for allergens and that it is possible to remove allergen from them – like bedding, toys, and flooring. And some of them relate to household products that should make as little an impact on the indoor environment as possible – like flooring and paint.

You can find out which products are certified asthma & allergy friendly® and read more here: www.asthmaandallergyfriendly.com


air filters, HVAC, furnace filters, science, testing, Certification Program, asthma, allergy, allergy insights, healthier home, indoor air quality, indoor environment

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By |2020-10-01T15:18:47+00:0030 November 2019|Tags: , , , |Comments Off on Why and how we certify in-car cabin filters – a Q&A