Following the purchase of a Sky Quality Meter by Unihedron (http://www.unihedron.com/) several years ago, I began participating and submitting my meter readings to the Loss of the Night App which is a Citizen Scientists project. They released a paper January 19, 2023 based on their findings which I thought may be of interest to you. This effort found that limiting magnitude is decreasing at a rate of about -0.044 magnitudes per year from 2011 to 2022 averaged over the Globe at Night viewing locations. The link to the paper is: https://www.science.org/doi/10.1126/science.abq7781
I was initially drawn to this project from a desire to be able to quantitatively determine how dark my observing skies were during the 2020 timeframe following the upgrade of my telescope equipment. I chose the Sky Quality Meter-L as this meter contains a filter which makes it sensitive to visual light only and I am currently primarily a visual amateur astronomer. Also, my primary observing site is from my home which is located in a northwest suburb of Philadelphia which has a lot of low level light pollution. Here is a link to a comparison of the two handheld Sky Quality Meters Unihedron produces which compares the differences between their standard and L model meters: http://unihedron.com/projects/darksky/images/fovcurves.jpg
There was an additional information card contained with the meter I received from Unihedron which made me aware of the International Dark Sky Association and Globe at Night Webapp for reporting my Sky Quality Meter readings in an effort to help support scientific data gathering for use in scientific studies. I began submitting my meter readings during each monthly campaign period when the moon is not a factor and when weather conditions would allow me to take good meter readings about an hour after sunset near the zenith of the sky. I found this exercise helpful to me in determining if the evening would be a good one for observing and for helping me understand how sky conditions can affect what I am able to see through my telescope.
If you are not currently participating in the data collection and contribution to this program and would like to, information on how to participate can be found on the Globe at Night Website via the following link: https://www.globeatnight.org/
The Globe at Night Webapp (https://www.globeatnight.org/webapp/) will take you directly to the reporting page where you can record your observations to this project. Data submittal includes the ability to submit your Sky Quality Meter readings and earn credit for your contribution if you have a SciStarter account.
There are many ways to contribute to the data collection effort in addition to submitting Sky Quality Meter data including guided visual observations. The 2022 program effort finished strong with 19,948 observations and they are asking for help in reaching a goal of 20,000 data points for 2023. The link to the campaign dates & constellations for 2023 can be found here: https://www.globeatnight.org/6-steps.php
Additionally, Al Lamperti who currently serves as the DVAA's contact to the Astronomical League recently received approval to include this Citizen Science project as part of the Astronomical League's Citizen Science Program (of which he is coordinator). Specifically Level 3: Projects Requiring Direct Observations. There are 3 levels, Bronze, Silver, Gold, representing 100, 500 & 1,000 observations. Here is the link to that program: https://www.astroleague.org/content/citizen-science-special-program
In the event you are already participating in this program and if your total observations uploaded to the Loss of the Night site meets one of the criteria listed above, you can send Al (off line) a screenshot of your total. You'll get a certificate electronically and your name etc in a future issue of the Reflector.
Clear skies to all and hopefully darker skies too through efforts such as these.
Stan