Modern Building Services

12 MODERN BUILDING SERVICES JULY/AUGUST 2021 INDOOR AIR QUALITY FEATURE INDOOR AIR QUALITY Winds of change: Why building ventilation has never been so important New research shows mechanical ventilation halves the risk of spreading airborne diseases in schools and offices compared to natural ventilation. Albert J Diaz Carrasquer and Jordi Lanuza Fabregat CFD Engineers – Aerodynamics and Acoustics Lab., R&D make the case for a reinvention of attitudes to indoor air quality. L ike electric cars and virtual events, future historians are likely to regard 2021 as the year when indoor air quality (IAQ) finally went mainstream. For decades, we have been wary of outdoor air pollution. Toxic air is responsible for one in nine early deaths globally. It kills seven million people a year: more than HIV, tuberculosis and malaria combined. Vehicle fumes and fossil fuel burning are the major culprits. But the Covid pandemic has brought into much sharper focus indoor air quality. We are now very conscious of the air that we breathe indoors, where we spend 90% of our time. The average adult breathes 18,000 and 20,000 times per day: Sucking in and filtering around 8,000 litres of air every day. At the same time, it’s been proven that poor indoor air quality and inadequate ventilation encourages the transmission of infectious diseases. The safest office will always be your own house. The cleanest restaurant will always be your kitchen. We know these environments are unlikely to harbour invisible clouds of diseases. But with ‘normal life’ tantalising close as the pandemic hopefully reaches its final stages, in the UK at least, we’re hearing from so many genuinely concerned businesses about what to do next – about how to reopen safely and with confidence. Is opening a few windows this summer good enough? What about the winter, energy efficiency, and the weather, noise and pollution? There’s plenty of generic advice but building owners are crying out for official and clear-cut guidance. The failure to distinguish between indoor mechanical or natural ventilation as part of this debate is also not surprising as we’re facing a complex and new challenge. Albert J Diaz Carrasquer Jordi Lanuza Fabregat