Face masks have negligible negative effect on CO2 and O2 levels

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ISLAMABAD, October 12 (online): As the world gains access to more information about SARS-CoV-2, the virus that causes COVID-19, scientists have become increasingly convinced that masks can help reduce its spread.
The primary way that SARS-CoV-2 transmits involves viral particles entering a person’s respiratory tract. This typically happens after another person coughs, sneezes, or speaks near them, producing droplets or aerosols that transport the virus.
Consequently, face masks play an important role in reducing exposure to the virus and limiting the amount of the virus that a person can project toward others.
There is a growing consensus about the value of face masks in reducing the spread of SARS-CoV-2, though this has not always been the case.
Initially, little was known about the new virus and policy had to be developed based on the best available evidence, following scientific models that drew on data from earlier epidemics involving similar viruses.
As a consequence, guidance about mask wearing has varied from country to country, and some major health bodies, including the World Health Organization (WHO), have changed their advice over time.
In many ways, these changes and discrepancies are inevitable when providing advice about an urgent public health crisis while scientists are continually discovering new information. Dogmatically sticking to a position despite the changing evidence or offering advice when there is little evidence to justify it are unlikely to be better approaches.
However, research has shown that significant changes in official guidance reduce people’s trust in the science that is the basis of the policy.