HAZE

Indicator of our atmosphere's health

Haze, Mist or Fog ?

Often, haze is confused with mist and fog. During the early morning or after rain showers when temperatures are low and humidity is high, mist and sometimes fog forms in valleys and lowlands, gradually clearing when the sun reappears. Mist and fog are formed as a result of the condensation of water vapour on particulates suspended in the atmosphere. Meteorologically, mist is defined as being present if diminished visibility occurs (with no other weather condition being present) and relative humidity of the atmosphere at the surface of the earth is above 95%. When the horizontal visibility falls below 1000 metres the phenomena is classified as fog.

Is Haze Harmful ?

Haze originating from natural sources such as sea salt and soildust is generally harmless to humans. Slight, transient haze visible in most towns and cities has not been proven to cause any serious long-term health effects on the population. However, during a severe haze episode, prolonged exposure to high concentrations of particulates can be harmful to health. Associated with previous haze episodes, there have been reports of increases in incidences of eye and throat irritations and respiratory difficulties among sensitive groups. During a haze episode, the public are strongly urged to follow the advice issued by the local health authorities.

How Can We Reduce The Incidence Of Haze?

Firstly, we should refrain from open burning of waste. Most incidences of local haze can be traced to this activity. Motor vehicles, due to their increasing numbers, are also major sources of haze particulates in urban areas. To reduce haze, vehicles should be well maintained. Choose fuels which are the least polluting. Large scale land clearing which exposes large tracts of barren land, not only results in soil erosion and degradation, but also provides a source of particulates to the atmosphere. Promoting efforts such as rapid replanting and staggered land clearing can reduce haze. Remember that every individual has a role to play to preserve the quality of our environment as a legacy for our future generations.

What Is The Government's Role?

The two Federal agencies directly involved with matters relating to haze are the Department of Environment (DOE) and the Malaysia Meteorological Department (MMD), which are under the Ministry of Science, Technology and the Environment. MMD monitors atmospheric conditions related to weather as well as some parameters relating to the ambient air quality. One of the parameters measured is suspended particulate (TSP) concentration in air which is directly related to haze intensity. Other meteorological parameters such as horizontal visibility, relative humidity and wind velocity are useful indicators in understanding the haze phenomenon and forecasting its occurrence and dispersal. The monitoring and research activities conducted by MMD is part of the national effort to control and mitigate haze.

Taking TSP measurement

Close cooperation among all related government agencies, local authorities and the mass media are essential during a haze episode to ensure all necessary data required for decision making is acquired, and any advice is rapidly disseminated to the public. At the regional level, ASEAN has initiated an ASEAN Cooperation Plan on the Management of Transboundary Pollution to address issues such as transboundary haze.

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