Last year, Rosa Ma and her eight-year-old daughter boarded the ferry in Mui Wo and headed into town for a ballet lesson. As soon as they disembarked at the Central ferry terminal, Ma's daughter, Sun-yi, became uncomfortable. 'She said she felt attacked by the dust on her face,' says Ma.
By the end of the lesson, Sun-yi was having trouble breathing. Racing against a full-blown asthma attack, they boarded the ferry home, where, in south Lantau's clean air, the little girl was finally able to regain her breath.
Sun-yi, who suffers from asthma and eczema, has been diagnosed with an elevated immunoglobulin level that makes her 17 times more sensitive to the environment than other children her age. Ma monitors the air quality index every morning to ensure it's safe for her daughter to venture outdoors.
Yumi Yeung, another Mui Wo resident, moved to the area from Aberdeen with her family seven years ago to seek relief for her youngest son, who suffered serious asthma attacks every two to three months that required being admitted to hospital. Doctors seemed powerless to help and medication offered no relief. After the move, however, the boy's condition improved rapidly. The asthma attacks stopped and within six months he was off medication.
For families such as these, south Lantau offers more than a pretty beach: it represents a chance for normality and a childhood free of debilitating health problems. But with the government's plan to build a mass burn incinerator just six kilometres away on Shek Kwu Chau island, parents such as Ma and Yeung feel their children's health is under attack.
For now, the plan is on hold. Last month, the Environment Bureau was forced to abandon its HK$23 billion funding request for the incinerator, leaving the decision of whether to move ahead with construction up to the next government. But it seems inevitable it will be built because the city's three major landfills are forecast to be exhausted by 2014, 2016 and 2018.
The effects of the new incinerator have been debated since 2008, when a shortlist of sites was announced. But such controversy is not limited to Hong Kong; incineration has been a hot topic worldwide for decades. There's even a Global Anti-Incinerator Alliance (GAIA), founded in 2010 and with a membership of more than 650 grass-roots groups, NGOs, and individuals in 90 countries.
Dr Kenneth Tsang Wah-tak, a respiratory medicine specialist in Hong Kong, says incinerators pose two main dangers: dioxins and airborne particulate matter.
'Dioxins are basically fumes that, depending on wind flow, can cause worsening cases of asthma in children,' says Tsang. Dioxins are also known carcinogens. '[Although] we don't know of a direct relationship between instances of cancer and incinerators, it would be easy to extrapolate that dioxins could expose kids to a risk of the development of cancer later on.'
According to the World Health Organisation, experiments have shown that dioxins affect a number of organs and systems. Dioxins that enter the body - typically through food - endure a long time because of their chemical stability and their ability to be absorbed and stored by fat tissue. Dioxins have a half-life of an estimated seven to 11 years.
Meanwhile, particulate matter, Tsang says, goes directly into the lungs and is associated with the deterioration of lung function.
A 2008 report, 'The health effects of waste incinerators' by the British Society for Ecological Medicine, says two large cohort studies in the United States have shown that fine particulate air pollution causes increases in death from cardiovascular disease and lung cancer, among others. It also says that higher levels of fine particulates have been associated with an increased prevalence of asthma.
Nitrogen dioxide, another pollutant produced by incinerators, has been shown to inflame the lining of the lungs, increase the susceptibility to lung infection, and increase the likelihood of respiratory problems. Tsang says there are many other chemicals from incinerators whose dangers we are as yet unaware of.
Elvis Au, an assistant director at the Environmental Protection Department who is spearheading the Shek Kwu Chau incinerator project, says the plant will 'showcase the best technology in the world' and be 'totally different' to the old incinerator that closed down 20 years ago.
This new generation of incinerator ensures a cleaner burn by burning waste in a highly turbulent environment at 850 degrees Celsius for more than two seconds. This should ensure the complete combustion of all waste and organic material, including the toxic dioxin compounds. Toxic fly ash, a by-product of this process, will be collected, mixed with cement and disposed of in landfills.
To clean the chimney emissions, the facility will also use a combination of filtering technology, including selective catalytic reduction (to remove nitrogen oxides) and activated carbon (to remove dioxins).
The incinerator will be kept up to European Union standards, the most stringent in the world. 'That's why even a distance away, say, in Cheung Chau, about 3.5 kilometres away ... it is pretty safe. There is no significant impact at all,' says Au.
An EPD report in December last year notes that with the new incinerator, levels of nitrogen dioxide in Cheung Chau and south Lantau are projected to rise to 17 and 26 micrograms per cubic metre respectively. This is still below the stated government air quality objective of 80 micrograms per cubic metre - and WHO's recommended healthy level of 40 micrograms per cubic metre.
For the most part, the real impact of modern incinerators on health is still unknown. Most published epidemiological studies relate to older incineration plants. Epidemiology, by its nature, after all, involves retrospective studies.
'Proponents of new facilities tend to dismiss the older research as irrelevant,' writes Professor Vyvyan Howard, a toxico-pathologist with the University of Ulster, in a 2009 statement to the Ringaskiddy Incinerator inquiry in Ireland. 'Opponents take a contrary view, arguing, not unreasonably, that similar claims of safety were made in relation to those older facilities when they were operating.'
Howard adds: 'The modern incinerators tend to be much larger than those operated historically, so that although the emissions concentrations have reduced, the total mass of pollutant emissions may even increase.'
There's no doubt that something must be done about Hong Kong's looming waste crisis. We produce 13,800 tonnes of waste per day - among the world's most prolific trash producers.
But nobody wants anything potentially unpleasant in their neighbourhood and the 'not in my backyard' phenomenon can stall vital public works projects indefinitely.
Yeung says something as small as recent local roadworks were enough to put her son in hospital with an asthma attack.
'I moved into a rural area to avoid the pollution of cities - where my son could have a healthier environment to grow up in,' she says. 'There are so few truly 'rural' areas in Hong Kong; it is wrong of the government not to protect them.'
Au says the site was chosen only after a 'very objective, vigorous, systematic site search process starting with 21 sites all over Hong Kong'. Shek Kwu Chau was chosen over Tuen Mun mainly in an attempt to more fairly distribute unwanted facilities across Hong Kong. Tuen Mun is already home to a landfill and a proposed sludge incinerator.
Au says he has been tirelessly meeting with community members to reassure them. Since 2008, he's had 120 different consultation engagement activities. But his work does not seem to have had the desired effect.
Says Ma: '[Au] says we've been consulted, but is he listening?'
- The date by which all three of Hong Kong's major landfills are projected to be exhausted