Mar 12Why early birds stay up late and night owls wake up earlyYour circadian system wants to wake up at a certain solar time. People love to talk about the circadian system, because it seems like the most obvious thing in the world — the sun comes up and goes down, and clearly this has some effect on our biology, since we…6 min read6 min read
Jul 22, 2022Stopping the SuperspreaderThe case now for air quality & taming the most risky spaces — It’s the middle of 2022, and most folks in the US have given up COVID mitigations. Big conferences, indoor dining. It’s basically over, despite record rates of transmission and new variants on the horizon. Why did people stop every mitigation earlier this year, rather than picking some halfway mark? …5 min read5 min read
Dec 18, 2020CO₂ sensors are magic COVID findersRecently, I wrote about practical ways to ventilate for COVID-19, and why this is important. The idea from medical facilities and building scientists is that you want to optimize for “ACH” (or “air changes per hour”). This is a good start, because more air movement is better. …2 min read2 min read
Aug 4, 2020How to Ventilate for COVID-19Since the pandemic started, lots of people have been infected indoors. Good ventilation helps reduce the number of viruses you breathe in, and it can make spaces a little bit safer during the COVID-19 pandemic. First, you should read Zeynep Tufekci’s article on the issues associated with “short-range aerosol” transmission…Ventilation5 min readVentilation5 min read
Jun 25, 2020Some notes on “far UV-C” lightCan we use a new kind of UV-C light in occupied spaces? — In 1903, Niels Finsen was awarded the Nobel Prize for using UV-C light for disinfection, originally for lupus. Since then, UV-C has been used in tackling Tuberculosis and MRSA in hospitals. Recent interest in UV-C for COVID-19 has involved disinfecting air (since there is potential for the virus to transmit…Covid-193 min readCovid-193 min read
Jun 13, 2019Position Letter to the California Senate: AB-7, permanent Daylight Saving TimeJune 3, 2019 To the Committee on Energy, Utilities, and Communications, I write to oppose AB-7, and I hope to convince the committee that permanent DST will wake people up too early throughout the winter, restricting how much they sleep. …Health3 min readHealth3 min read
Mar 20, 2019Why Standard Time is betterWe have to stop changing the clocks twice a year, but it’s also important to pick the right schedule when we do it. Thousands of scientists say that Standard Time is better, yet legislators are pushing for permanent DST, anyway. …Sleep17 min readSleep17 min read
Oct 7, 2015Circadian RealityVR glasses are going to affect sleep like nothing we’ve ever seen I took my iPhone 6 and popped it into Google Cardboard. Put the spectrometer where my eyes usually go, and pushed the button. The meter took the reading really fast… 360 lux f.luxometer says that’s 90% as bright as daylight — meaning it can kick your circadian clock two timezones…Virtual Reality3 min readVirtual Reality3 min read
Jan 14, 2014On Really Bright ScreensThey’re good for more than the movies — Dolby just announced their Dolby Vision project. To make movies look better, they’re testing incredibly bright screens—20,000 nits—making so much heat they have to use liquid cooling. Normal screens clock in at just 200-400 nits, so it’s quite a jump. I’m sure the images look splendid, but that’s not why…2 min read2 min read