Interactions of sunlight and nitrophenol (IMAGE) Hokkaido University Caption In the atmosphere, sunlight breaks down nitrophenol to form nitrous acid (HONO), which leads to photochemical smog (Taro Sekikawa). Credit Taro Sekikawa Usage Restrictions This image is copyrighted but may be used to report this press release if credited as instructed. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.