{"id":226,"date":"2017-02-16T23:59:16","date_gmt":"2017-02-16T23:59:16","guid":{"rendered":"http:\/\/ciresblogs.colorado.edu\/air-quality-in-slc\/?p=226"},"modified":"2017-02-16T23:59:16","modified_gmt":"2017-02-16T23:59:16","slug":"night-flying","status":"publish","type":"post","link":"https:\/\/ciresblogs.colorado.edu\/air-quality-in-slc\/2017\/02\/16\/night-flying\/","title":{"rendered":"Night flying"},"content":{"rendered":"
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Salt Lake City at night<\/p><\/div>\n

While emissions that affect air quality are released mostly during the day, there is still chemistry at night that determines how long certain pollutants stick around. This is particularly true for \u00a0the chemistry of nitrogen oxides.\u00a0 NOX<\/sub> (NO and NO2<\/sub>) is emitted from a variety of sources, both natural and human caused. In the winter, the primary sources in this area are combustion-based: power plants, automobile engines and wood burning. When the sun goes down, NO2<\/sub>\u00a0(which forms predominantly during the day from the reaction of emitted NO and\u00a0other atmospheric chemicals) builds up and reacts further to form compounds with more oxygens. The three compounds \u00a0that determine overnight removal of NOX<\/sub>\u00a0from the atmosphere are: N2<\/sub>O5<\/sub>, ClNO2<\/sub>\u00a0and HNO3<\/sub>. Each of these has different fates the next morning. N2<\/sub>O5<\/sub>\u00a0returns\u00a0back to NOX<\/sub>, so we call it a \u201creservoir species.\u201d ClNO2<\/sub> will form NOX<\/sub> and a Cl atom. HNO3<\/sub>, on the other hand, usually gets removed from \u00a0the atmosphere without undergoing further chemistry. The balance between these different nighttime species is very important, as it determines how long NOX<\/sub>\u00a0pollution persists in the atmosphere and, therefore, how far it is able to travel from its initial emission source.<\/span><\/p>\n

Preflight preparations in the dark<\/p><\/div>\n

To investigate this overnight chemistry, we have to fly at all hours of the night. Since the plane has been repaired from its bird strike, we\u2019ve been trying to characterize the nighttime chemistry of the area. We\u2019ve taken off at midnight, 2 am, 6 am and other crazy times in an attempt to capture the full extent of what happens overnight. These flight times create unusual sleep schedules for both scientists and pilots and require some finagling to fit in pilot rest requirements. When we have a 2 am takeoff, the scientists need to be at the\u00a0hangar at 11 pm for preflight, while the pilots show up at 12:30 to make sure the plane is ready to go.<\/span><\/p>\n

The moon reflected in the Great Salt Lake<\/p><\/div>\n

While our sleep schedule gets disrupted and flying altitudes are more limited, there\u00a0are some\u00a0awesome aspects\u00a0to night flying. Aside from the science,\u00a0which has been very interesting\u00a0at night, we\u2019ve\u00a0seen the moon\u00a0reflect off the Great Salt Lake at 11\u00a0pm and we\u2019ve watched the sun rise over the Wasatch Mountains in the early morning. While it\u00a0may be 7 am and everyone on the plane has been up through a long night, seeing the sun peek out between the mountains and watching the atmospheric chemistry transition back to\u00a0its usual daytime makeup is always worthwhile.<\/span><\/p>\n

The sun rises over the Wasatch Mountains in Utah Valley<\/p><\/div>\n

It turns out the night schedule was useful in other ways as well. When two of us drove the U-Haul back to Boulder with the equipment, through a series of unplanned incidents, we wound up returning at 3:30 am. After all those night flights,\u00a0we were well prepared for a night of driving!<\/span><\/p>\n

 <\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

While emissions that affect air quality are released mostly during the day, there is still chemistry at night that determines how long certain pollutants stick around. This is particularly true for \u00a0the chemistry of nitrogen oxides.\u00a0 NOX (NO and NO2) is emitted from a variety of sources, both natural and human caused. In the winter,… Read More<\/a><\/p>\n","protected":false},"author":105,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-226","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"jetpack_featured_media_url":"","publishpress_future_action":{"enabled":false,"date":"2026-05-19 11:43:19","action":"change-status","newStatus":"draft","terms":[],"taxonomy":"category"},"publishpress_future_workflow_manual_trigger":{"enabledWorkflows":[]},"_links":{"self":[{"href":"https:\/\/ciresblogs.colorado.edu\/air-quality-in-slc\/wp-json\/wp\/v2\/posts\/226","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ciresblogs.colorado.edu\/air-quality-in-slc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ciresblogs.colorado.edu\/air-quality-in-slc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ciresblogs.colorado.edu\/air-quality-in-slc\/wp-json\/wp\/v2\/users\/105"}],"replies":[{"embeddable":true,"href":"https:\/\/ciresblogs.colorado.edu\/air-quality-in-slc\/wp-json\/wp\/v2\/comments?post=226"}],"version-history":[{"count":17,"href":"https:\/\/ciresblogs.colorado.edu\/air-quality-in-slc\/wp-json\/wp\/v2\/posts\/226\/revisions"}],"predecessor-version":[{"id":247,"href":"https:\/\/ciresblogs.colorado.edu\/air-quality-in-slc\/wp-json\/wp\/v2\/posts\/226\/revisions\/247"}],"wp:attachment":[{"href":"https:\/\/ciresblogs.colorado.edu\/air-quality-in-slc\/wp-json\/wp\/v2\/media?parent=226"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ciresblogs.colorado.edu\/air-quality-in-slc\/wp-json\/wp\/v2\/categories?post=226"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ciresblogs.colorado.edu\/air-quality-in-slc\/wp-json\/wp\/v2\/tags?post=226"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}