KUALA LUMPUR: Air pollution, especially haze, may influence Covid-19 transmissions and can have adverse effects on patients recovering from the virus, experts said.
Professor Dr G. Jayakumar of Melaka Manipal Medical College's Community and Occupational Medicine said emerging research indicated that exposure to air pollution, especially nitrous oxide and fine particles in the air (PM2.5), might increase the susceptibility to infection and death from Covid-19.
Therefore, he said, the poor communities, homeless and migrant workers who resided in shanty homes, as well as the elderly with pre-existing medical conditions, exposed to air pollution required special attention.
"They are at higher risk of developing complications from Covid-19 infections. These groups will have to be prioritised for Covid-19 vaccination, with physical distancing re-emphasised," he told the New Straits Times.
Particulate matter 2.5, or PM2.5, refers to tiny particles or droplets in the air that are 2.5 microns or less in width that reduce visibility and cause the air to appear hazy when levels are elevated.
The Meteorological Department had earlier cautioned that the hot spell, which is expected to last until next month, could trigger haze, drought, forest fires, and reduction in dam water levels.
Up to 5pm on March 6, it said nine areas in the peninsula had been issued a yellow-level heatwave alert, which denotes a daily maximum temperature of 35°C to 37°C for at least three consecutive days.
The areas were Kuala Lumpur, Petaling Jaya, Sepang, Tampin, Alor Gajah, Central Melaka, Jasin, Tangkak, and Batu Pahat.
Sabah and Sarawak saw no heatwave, and the maximum daily temperatures in the two states and other states in the peninsula were less than 35°C.
Dr Jayakumar said during the hot weather, people, especially vulnerable groups like the elderly heading out to vaccination sites, should drink plenty of water even if they did not feel thirsty.
"They should schedule their trip carefully, wear loose, lightweight, light-coloured clothing.
"Heat can trigger exhaustion and heatstroke and can aggravate existing conditions, such as heart, respiratory, kidney or mental diseases.
"Firefighters, bakery workers, farmers, construction workers, boiler room workers and policemen or army personnel on external duty under the sweltering sun are at high risk of experiencing heat stress or, in severe situations, succumbing to heatstrokes."
On concerns over vaccination efficacy and storage, he said the external weather was unlikely or had little influence on the storage and transportation of vaccines as they were kept in a controlled environment.
Many types of vaccines, he said, should be stored and transported via a cold supply chain and public health officials had found ways to keep vaccines ultra-cold at extreme temperatures of between –80°C and –70°C.
He said at the onset of the pandemic, there were hopes that hot temperatures could reduce the spread of the virus.
However, he said, a recent study involving 202 locations in eight countries showed that warmer weather alone was unlikely to reduce Covid-19 transmissions.
"The transmission of the virus from one person to the next depends almost entirely on human behaviour."
Universiti Selangor visiting professor of Environmental Health Dr Jamal Hisham Hashim said Covid-19 and air pollution tend to exacerbate the health of those with pre-existing medical conditions, like hypertension, chronic respiratory and cardiovascular diseases.
These medical conditions, he said, tend to occur in the elderly, who were also equally at risk from both air pollution and Covid-19.
"A Harvard study found that people who live in areas with high levels of fine particulate pollution are eight per cent more likely to die from Covid-19."
He said the hot and dry weather would trigger forest fires, which lead to hazy conditions.
"PM2.5 in haze can penetrate deep into the alveolar region of the lungs. Pneumonia due to severe Covid-19 also attacks the same region of the lungs, the lower respiratory tract."
While studies showed that Covid-19 survives well in low temperatures and humid conditions, with a report noting that temperatures above 55°C for five minutes could inactivate the coronavirus, he said the current hot weather might affect virus survival outdoor, but not enough to inactivate or kill it.
With the Conditional Movement Control Order and Recovery MCO in effect, Jamal said people should limit their time outdoors, especially the elderly and those with chronic medical conditions.
"Stay hydrated and stay in the shade as much as possible.
"In hot weather, the difference in temperatures under direct sunlight and in the shade can be significant. Homeless people should be given temporary shelter and medical care if the hot weather is prolonged and worsens."
The Meteorological Department said Malaysia was in the final phase of the Northeast Monsoon season, which was expected to continue until the middle of the month.
During this period, it said, rainfall distribution in some areas was low in the peninsula, particularly in the northern region.
However, the department did not expect unusually hot weather conditions to occur this year.
Low rainfall over a period of several weeks could cause the weather to become hotter, especially at night when there was no cloud, it added.
Up to 5pm yesterday, Rompin district in Pahang was the only area with an unhealthy air quality reading with an Air Pollutant Index (API) reading of 106, with 25 other areas recording moderate air quality.
API readings of between 0 and 50 denote good air quality; 51 and 100, moderate; 101 and 200, unhealthy; 201 and 300, very unhealthy; and over 300, hazardous.