Richard, according to NIWA the maximum summer value for UVI in New Zealand is generally about 12. Published data from Lauder shows that Ozone atmospheric concentration is lowest in March and the latest measurement for March 2024 is close to the historical average for this time of the year. However, Whangarei recorded only 7.8 maximum today 22nd March and yesterday 21st. Why were these measurements for Whangarei today and yesterday much lower than 12?
This is great info, I was actually just looking into this. I read that there is a difference between prescription glasses using glass or using plastic. Plastic blocking UV rays and glass not really blocking them. I wonder if your test implies that all these glasses were made of some sort of plastic, or if there also we're actual glass lenses among them which only block UV rays due to whatever custom coating they had.
Furthermore I noticed the remark about SPF 50 implying UVA has to get blocked as well.
This is news to me, I understood SPF to only refer to UVB rays. Could you elaborate on the connection here?
Can you make any kind of deductions about the amount of UVA being blocked from the SPF value? Since sunscreen manufacturers don't tell us about the amount of UVA being blocked specifically.
Richard, according to NIWA the maximum summer value for UVI in New Zealand is generally about 12. Published data from Lauder shows that Ozone atmospheric concentration is lowest in March and the latest measurement for March 2024 is close to the historical average for this time of the year. However, Whangarei recorded only 7.8 maximum today 22nd March and yesterday 21st. Why were these measurements for Whangarei today and yesterday much lower than 12?
This is great info, I was actually just looking into this. I read that there is a difference between prescription glasses using glass or using plastic. Plastic blocking UV rays and glass not really blocking them. I wonder if your test implies that all these glasses were made of some sort of plastic, or if there also we're actual glass lenses among them which only block UV rays due to whatever custom coating they had.
Furthermore I noticed the remark about SPF 50 implying UVA has to get blocked as well.
This is news to me, I understood SPF to only refer to UVB rays. Could you elaborate on the connection here?
Can you make any kind of deductions about the amount of UVA being blocked from the SPF value? Since sunscreen manufacturers don't tell us about the amount of UVA being blocked specifically.