Respiratory Health in Singapore and Herbal Options

I recently spent a couple of days in Singapore, where herbal product needs are currently somewhat different to those in my New Zealand home. September in Singapore generally marks the start of the 3-4 month so-called ‘Haze season’, a period in which the air can be tainted for days on end, with a haziness due to smoke drift from fires in nearby Indonesia. The annual haze season started early this year, in late August, and on 26 August Singapore’s 24 hour Pollutant Standards Index (PSI) entered the ‘unhealthy’ range of above 100, while its 3-hour PSI reached 215(1). As with the haze last year, when the PSI reading at times exceeded 300, most people didn’t venture out without a face mask.

Agricultural fires are an annual occurrence across Sumatra and in parts of Kalimantan on Borneo, as corporations as well as small-scale farmers use slash-and-burn methods to clear vegetation for palm oil, pulp and paper plantations. As well as trees and forests, there is much peat land in these parts of Indonesia, and peat fires can burn and smoulder underground for several months.

Tsmog-over-the-city-1197986-639x359he haze contains particulate matter, fine particulate matter, heavy metals and poly aromatic hydrocarbons, and at its peak can measure hundreds of kilometres across. As well as affecting Singapore’s air quality and visibility, the air pollution can spread to Malaysia, southern Thailand and the Philippines. This can have a major impact on the health of the people and plants of these countries, and of course those of Indonesia itself.

Fine particulate matter especially, can enter deep into the lungs, causing respiratory illnesses and lung damage. Particulate matter pollution and its constituents also damages plant morphological structure, flowering, water content, growth and reproduction, and can have genotoxic impacts(2). Epidemiological studies have shown an increase in morbidity and mortality rates from chronic obstructive pulmonary disease after exposure to elevated levels of air pollution, and associations between lung cancer and cardiovascular diseases, are well established.

This situation leads to increased demand for herbal lung health products in Singapore by the local population seeking to do more than wear a mask to protect their lungs against the damaging effects of the haze. Herbs that gently support and encourage the natural expectoration process of the millions of cilia cells lining our bronchial trees, whose role is to remove excess mucus and potentially harmful substances such as particulate matter or unwanted allergens, are therefore useful. These include mucilaginous (polysaccharide hydrocolloid rich) and expectorant herbs such as Marshmallow (Althaea officinalis), Mullein (Verbascum Thapsus) and the NZ native Hoheria (Hoheria populnea). Other traditional lung herbs such as Elecampane (Inula helenium), White horehound (Marrubium vulgare) and Hyssop (Hyssopus officinalis), are also useful. For Singaporeans having to live in the seasonal haze, or citizens of cities in China and many other countries where air pollution is a regular feature of life, in order to help protect against reduced levels of cellular oxygenation and an increased risk of bronchial congestion, asthma, lung cancer and heart disease, these herbs can be useful daily tonics.

In addition, certain herbs have chemo-preventive or protective effects against cellular damage and carcinogenicity, that may be helpful when exposure to air pollution is unavoidable. Apart from its anti-inflammatory, antimicrobial and antioxidant properties, evidence suggests a possible protective effects against lung cancer by roots of the warming volatile oil rich Elecampane(3).  The root of the fiery Horseradish (Armoracia rusticana)(4), and aerial parts of Nasturtium (Tropaelum majus),(5-6) also both contain phytochemicals with established chemo-preventive effects against cancers, that seem to be well absorbed into the bloodstream when taken orally. These and expectorant actions make them specifically indicated to help prevent lung damage in those exposed to regular dangerous levels of airborne pollution, such as the annual Haze in Singapore.

untitled-design-17While considering this situation, I couldn’t help notice the presence of palm oil still in chocolate sold throughout Singapore, unlike certain other countries where it has been removed due to public concerns around the environmental impacts of a huge increase in palm oil plantations. Similarly the importation of palm kernels for use as a supplementary feed to dairy cows in New Zealand, needs a mention. Reflecting on this as well as the widespread use of palm oil in cheap vegetable oils and in many other food and non food consumer items found globally, there is clearly a need to address the underlying cause of such environmental pollution and factors responsible for poor human health, in a more integrative way. This burning of indigenous forests in Indonesia is related also to poverty as well as poor regulation by authorities there, but corporate greed, consumer usage and lack of awareness or concern for environmental and economic impacts, is contributory.

Until the slash and burn method of land clearing in Indonesia is stopped, health effects on the millions of people living in the region, and ongoing widespread loss of bio-diverse rich forests and destruction of the habitat of endangered species such as orangutans, tigers, elephants and rhinos, will continue.



  1. “The haze is back across South East Asia”. BBC. Retrieved 26 August 2016.
  2. Rai PK, Ecotoxicol Environ Saf 2016; 129:120-136.
  3. Li Y et al, Z Naturforsch C 2012; 67(7-8):375-380.
  4. Weil MJ et al, J Agric Food Chem 2005; 53(5):1440-1444.
  5. Platz S et al, Anal Bioanal Chem 2013; 405(23):7427-7436.
  6. Pintao AM, Planta Med 1995; 61(3):233-236.