I would like to advice you dear Friends and Clients to use masks that are made of a cloth that can breathe - like a thick cotton mask, that can also be washed easily. This is especially if you are going to use it for a long period of time. Identifying airborne transmission as the dominant route for the spread of COVID-19 
Renyi Zhang, View ORCID Profile Yixin Li, Annie L. Zhang, View ORCID Profile Yuan Wang, and Mario J. Molina
PNAS first published June 11, 2020 https://doi.org/10.1073/pnas.2009637117 
 Significance We have elucidated the transmission pathways of coronavirus disease 2019 (COVID-19) by analyzing the trend and mitigation measures in the three epicenters. Our results show that the airborne transmission route is highly virulent and dominant for the spread of COVID-19. The mitigation measures are discernable from the trends of the pandemic. Our analysis reveals that the difference with and without mandated face covering represents the determinant in shaping the trends of the pandemic. This protective measure significantly reduces the number of infections. Other mitigation measures, such as social distancing implemented in the United States, are insufficient by themselves in protecting the public. Our work also highlights the necessity that sound science is essential in decision-making for the current and future public health pandemics. Abstract Various mitigation measures have been implemented to fight the coronavirus disease 2019 (COVID-19) pandemic, including widely adopted social distancing and mandated face covering. However, assessing the effectiveness of those intervention practices hinges on the understanding of virus transmission, which remains uncertain. Here we show that airborne transmission is highly virulent and represents the dominant route to spread the disease. By analyzing the trend and mitigation measures in Wuhan, China, Italy, and New York City, from January 23 to May 9, 2020, we illustrate that the impacts of mitigation measures are discernable from the trends of the pandemic. Our analysis reveals that the difference with and without mandated face covering represents the determinant in shaping the pandemic trends in the three epicenters. This protective measure alone significantly reduced the number of infections, that is, by over 78,000 in Italy from April 6 to May 9 and over 66,000 in New York City from April 17 to May 9. Other mitigation measures, such as social distancing implemented in the United States, are insufficient by themselves in protecting the public. We conclude that wearing of face masks in public corresponds to the most effective means to prevent interhuman transmission, and this inexpensive practice, in conjunction with simultaneous social distancing, quarantine, and contact tracing, represents the most likely fighting opportunity to stop the COVID-19 pandemic. Our work also highlights the fact that sound science is essential in decision-making for the current and future public health pandemics. https://www.pnas.org/content/early/2020/06/10/2009637117?fbclid=IwAR0hU-hobrFBWAOCRLr2zkJIG8G_gmOUXGD-pfPEq4OR9-pfur8yTBEnS_4 

READ DETAILS HERE. Below are the conclusions and references. Contrasting the trends of new infections between NYC and the United States. Daily new confirmed infections in ( A ) NYC and ( B ) the United States. The dotted lines represent linear fitting to the data between April 17 and May 9 in NYC and between April 4 and May 9 in the United States. In B , the number in NYC was subtracted from that in the United States. The vertical lines label the dates for social distancing, stay-at-home orders, and mandated face-covering.
