LONDON: Driving with the windows down and feeling the wind in your hair might be a nice experience but it won't bode well for your health as a study by Britain's niversity Surrey found.
The study revealed that with the windows down, it would increase the occupants' exposure to pollution by as much as 80% - even more so during peak hours.
The study was led by the university's Global Centre for Clean Air Research (GCARE) team of researchers and published by the Science of Total Environment journal. It looked at air pollution exposure levels for commuters in 10 cities around the world.
The cities were Dhaka in Bangladesh, Chennai in India, Guangzhou in China, Medellín in Colombia, São Paulo in Brazil, Cairo in Egypt, Sulaymaniyah in Iraq, Addis Ababa in Ethiopia, Blantyre in Malawi and Dar-es-Salaam in Tanzania.
It looked at how exposure levels changed for particulate matters from 2.5 to 10 micrometres (PM2.5 - 0.0025mm and PM10 - 0.01mm) from inside vehicles. Humans can only see down to 0.1mm at best with the naked eye - around the same width as a strand of human hair.
Exposure to particulates that are PM10 or less can irritate the eyes, nose and throat but once it reaches as small as PM2.5, these particles can not only penetrate deep into the lungs but also pass into the bloodstream.
The measurements were taken during peak hours (morning and evening) as well as during off-peak hours.
The scientists also measured exposure levels with the use of recirculation systems, fans and with the windows down.
The study showed that driving with the windows down increased pollution exposure by 90% with the safest being during non-peak hours with the windows up and air recirculation turned on (vents closed).
According to the World Health Organisation (WHO), 7 million people worldwide die from pollution-related causes while 90% breathe air with high pollutant levels.
The scientists' recommendation to cut pollution was to reduce the number of vehicles on the road or switch to cleaner alternatives.
As for commuters, travelling during off-peak hours would be ideal but obviously not practical since many hold down regular jobs.
In addition, PM2.5 has the ability to increase acidity levels in soil and water bodies making it more difficult for Earth to sustain life.
The US Environmental Protection Agency says that exposure to PM2.5 is fine as long as a person only breathes in an average of 12 micrograms per cubic metre (μg/m3) or less of it per day per year while WHO's guideline is at 10μg/m3.