When Air Resource Specialists, Inc. needed a data logger to withstand the remote extremes of our U.S. national parks and wilderness areas, they came to Campbell Scientific. The Clean Air Act of 1977 initiated a goal to protect visibility in 156 national parks and wilderness areas. From scorching Arizona summers to icy northern Montana winters, our data loggers have played a key role in monitoring the atmosphere's ability to scatter and absorb light. There are currently over 20 monitoring sites.