Tuesday, January 25, 2022

Botswana may struggle to now meet WHO pollution standards

Botswana might struggle to meet the new World Health Organisation (WHO) air quality guidelines following an announcement by the health agency that harms from air pollution begin at much lower levels than previously thought.


A year ago, the State of Global Air 2020 Report highlighted that Botswana is polluted twice beyond the threshold limit. The report noted that Botswana has high concentration of deadly particle pollution, recording the concentration of poisonous PM2.5 particles at two and half times over the WHO threshold limit. The 2020 report also noted that Botswana has high exposure to particle matter concentration at 25 micrograms per cubic metre which is above WHO’s Air Quality Guideline for PM2.5 of only 10 micrograms per cubic metre.


The health agency notes that since 2005, more evidence has emerged which shows that air pollution affects health at lower concentrations than previously understood. “WHO has adjusted almost all the air quality guideline levels downwards, warning that exceeding the new … levels is associated with significant risks to health,” the health agency said in a statement.


Furthermore, the health agency lowered acceptable thresholds for several pollutants, including ultrafine PM2.5 particles that Botswana has had a difficult time trying to contain.


PM2.5 are particles smaller than 2.5 micrometres in diameter – less than a 30th of the diameter of a human hair and capable of entering the bloodstream via the lungs. According to the new thresholds, the average 24-hour exposure to PM2.5 must remain below 15µg/m³, down from 25µg/m³. In case of PM10 particles – typical dust particles – the safe threshold has been lowered from 50 to 45µg/m³. In terms of exposure over a year-long period, the threshold for PM2.5 has been brought down from 10 to 5µg/m³ and for PM10, from 20 to 15µg/m³.


WHO says the major components of particle matter are sulphate, nitrates, ammonia, sodium chloride, black carbon, mineral dust and water; and are mainly emitted by coal-burning power plants, industrial activity, vehicle emissions, waste burning, and other human activities. 


An environmentalist who spoke to this publication on condition of anonymity indicated that by tightening global air pollution standards, WHO is appreciating that air pollution on health is much more serious than earlier envisaged. “The move by WHO sets stage for eventual shift in policy in Botswana towards evolving newer stricter standards. The reasons why it is difficult for particle pollution to be addressed in Botswana are firstly, Botswana does not have sufficient smart technologies; and second the country lacks better air quality management plans.


The new WHO pollution guidelines which aim to protect people from the adverse effects of air pollution and are used by governments as a reference for legally binding standards. It is not immediately clear how this will affect policy in Botswana as the country announced a few months ago that they are ramping up the use of coal to reduce over dependence on diamonds.

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