THE prevailing dust haze that has enveloped the country's airspace in the past two weeks clearly heralds the harmattan season, a weather transition from the wet humid condition to a dry dusty spell with chilly nights most of the time. The season, which may last a couple of months or longer in parts of the country, presents a peculiar character requiring modifications in daily life experience, particularly with regard to health and travel.So far, the weather has been characterised by hot afternoons, sweaty nights and early morning chills, which is a slight departure from the usual weather pattern associated with harmattan. The condition may not be unconnected with the global climate change, which tends to alter established climatic patterns. This year's harmattan appears to have started virtually all over the country, again unlike sometimes when the season does not manifest until the New Year.Accordingly, the Nigeria Meteorological Agency (NIMET) has predicted that the prevailing weather condition is likely to herald long and severe harmattan in the months ahead. The Agency said Nigerians should expect 'proper' harmattan, which could mean a rare severe weather. People should, therefore, embark on measures to adjust accordingly to avoid unpleasant consequences.Incidentally, the weather coincides with the yuletide and end of the year, a period of high rate of travelling. Motorists should be cautious because the harmattan haze reduces visibility and thereby put travellers at further risk. Fire outbreaks are common during harmattan, again due to the dry atmosphere. There is need for conscious effort, including public enlightenment, to guard against such incidents.Harmattan is a cold dry and dusty wind that originates from the Sahara desert due to shift in atmospheric high pressure belt to the northern hemisphere, while the entire southern hemisphere is under low pressure system. As air mass moves from zone of high pressure to low pressure, the traditional northeast trade winds, laden with this air mass from the Sahara desert, heads towards the West Africa sub-region. This condition usually coincides with the northern winter, when the entire temperate northern hemisphere is experiencing heavy snowfall. The main physical characteristics are poor visibility, diffused radiation, low temperatures and low relative humidity.The impact of harmattan on social and economic activities depends on the severity of the physical characteristics of the air mass. The severity could be attributed to extraneous global factors like climate change. The harmattan tends to make people lethargic. The prevalence of dust particles is unhealthy for people with respiratory tract infections. Asthmatic patients in particular should be wary against exposing themselves to the dust. As far as possible, they should stay indoors.A host of other ailments are aggravated during harmattan. These include eye irritations, pneumonia, catarrh and cough. The dry condition affects the skin and causes lips to crack. However the chill may induce longer hours of sleep, while sweating and heat rashes disappear. The fine dust particles settle on furniture pieces, cars, rooftops, window panes and on the surface of other objects, making frequent cleaning imperative.Horizontal visibility is poor especially during early mornings. Vehicle drivers should be most careful, as driving can be hazardous. Automobile accidents are more common in harmattan, a fact compounded by the deplorable state of our roads. Bright and effective headlamps should not be compromised.It is common during this season for the aviation industry to suffer huge losses due to flight cancellations in extreme weather condition. A horizontal visibility of 1000 metres affects aircraft operation. Flights may be cancelled at the last minute and air passengers stranded. Luckily, most flights are still making their scheduled rounds. It is important, however, for aviation authorities and operators to appreciate the dangers posed by harmattan. The Nigerian aviation authorities need to update their technology to ensure safer flight operations during severe weather.On a positive note, harmattan favours agricultural activities to flourish. Fruit trees like mangoes, avocado, guava, and pears, among others flower during this period. Remarkably, therefore, a severe harmattan usually heralds fruitful harvest. Farmers use the period to clear farms and get them ready for planting. However, bush burning should be done with utmost caution to avoid setting forests ablaze.Ordinarily, there should be no cause for alarm during harmattan. The only problem is that most people are often caught unawares yearly. There is need therefore for all Nigerians to educate one another on the harmattan phenomenon, and make prepare early against its harmful elements.
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