When Hong Kong artist Erin Hung bought her “dream home” five years ago – a walk-up with a rooftop surrounded by trees and mountains in the city’s Pok Fu Lam neighbourhood – she did not expect it would affect her health.“In the first year, the mould started kicking in across the whole house,” she recalls. “Sometimes the walls would drip with moisture.”In subtropical Hong Kong, black mould is a chronic health hazard. In the relentless humidity, it takes root on damp plasterboard and concrete, digesting organic material while shedding cellular debris and toxins that trigger asthma, stubborn coughs and chronic allergic reactions.Hung’s own allergies flared up, with symptoms escalating to a chronic cough, runny nose and itchy eyes, but she ruled out standard anti-mould treatments. Most commercial remedies rely on aggressive chemical agents, including biocides and fungicides, to destroy spores. For Hung, swapping organic mould for harsh synthetic chemicals felt like a counterproductive trade-off.Artist Erin Hung and her family could breathe easier in their home in Hong Kong’s Pok Fu Lam neighbourhood after they took steps to keep mould at bay. Photo: Jenna Louise Potter“As an artist, it is sometimes unavoidable to use chemicals in my work, so it is important that my home is free of chemicals and close to nature,” she says, referring to the synthetic toxins found in typical house paints.At first, she turned to ventilation and heat treatment, using moisture-absorbing silica gel packets, and heating rods that gently raise the temperature. She put dehumidifiers in each room.