{"id":4005,"date":"2015-07-23T03:32:56","date_gmt":"2015-07-23T03:32:56","guid":{"rendered":"http:\/\/www.lifeandnews.com\/articles\/?p=4005"},"modified":"2015-07-23T03:32:56","modified_gmt":"2015-07-23T03:32:56","slug":"low-cost-sensors-track-co2-where-it-counts","status":"publish","type":"post","link":"https:\/\/www.lifeandnews.com\/articles\/low-cost-sensors-track-co2-where-it-counts\/","title":{"rendered":"Low-cost sensors track CO2 where it counts"},"content":{"rendered":"

Alexis Shusterman<\/a>, University of California, Berkeley<\/a><\/em><\/p>\n

Earlier this summer, climate change was once again thrust into the global limelight, this time by an unlikely source \u2013 the pope. In his 184-page On Care for Our Common Home<\/a>, Pope Francis warned:<\/p>\n

\u201cA very solid scientific consensus indicates that we are presently witnessing a disturbing warming of the climatic system. [\u2026] A number of scientific studies indicate that most global warming in recent decades is due to the great concentration of greenhouse gases (carbon dioxide, methane, nitrogen oxides and others) released mainly as a result of human activity.\u201d<\/em><\/p>\n

Calling on his followers to take action at last, Pope Francis\u2019 encyclical may represent a turning point in worldwide attitudes toward global warming. And with the UN Climate Change Conference<\/a> hitting Paris this November, greenhouse gas regulation could soon become widespread.<\/p>\n

The next question becomes: how will any regulations aiming to limit emissions be evaluated and enforced? Everyone wants reassurance that their neighboring countries are playing by the rules, but not all UN signatory nations can afford<\/a> to provide detailed emissions reports<\/a> using the conventional techniques.<\/p>\n

Orbiting satellites<\/a> can detect regional CO2 concentrations from space, but fall short when it comes to representing more intricate patterns. Ground-level CO2 monitors<\/a> can quantify emissions at a specific location, but the favored technology is still too expensive for common use. And yet, effective carbon regulation<\/a> needs to take place on hyperfine spatial and time scales \u2013 right down to the individual freeways and neighborhoods hiding in these methods’ blind spots.<\/p>\n

To document the complex emission patterns<\/a> from urban CO2 sources, it would take a veritable army of sensors, packed into the atmospheric nooks and crannies of a city.<\/p>\n

That\u2019s where we come in.<\/p>\n

Distributed network<\/h2>\n

I work on a project called BEACO\u2082N, which stands for the Berkeley Atmospheric CO2 Observation Network. BEACO\u2082N is a web of about 30 low-cost CO2-sensing monitors, or \u201cnodes,\u201d installed at two-kilometer (1.24-mile) intervals across the city of Oakland, California.<\/p>\n

At this scale, it is the densest collection of CO2 monitoring instruments in the world.<\/p>\n

The nodes utilize popular open-source microcontrollers<\/a> and computers<\/a> that transmit their measurements wirelessly using a simple smartphone data plan. The data are then made publicly available<\/a> in near-real time.<\/p>\n

The sensors<\/a> themselves measure changes in infrared light intensity to calculate CO2 concentrations in the air. Carbon dioxide absorbs infrared radiation, so more CO2 molecules floating across the light beam means that less light reaches the detector on the other side. It\u2019s the same operating principle behind more expensive CO2 sensors, but using lower-grade lamps and detectors. This small compromise in accuracy means an entire BEACO\u2082N node can be assembled for about US$5,500. That\u2019s 10\u201320 times less than conventional monitors, and cheap enough to be bought in bulk. And in this big-data era, providing more measurements at lower cost has broad appeal.<\/p>\n

By blanketing the city with a tight \u201cgrid\u201d of sensors, potential CO2 sources can be identified and quantified simply by comparing signals from adjacent nodes<\/a>. A higher CO2 level measured at the downwind node relative to its upwind neighbor indicates the presence of a CO2 emitter in between the two. This simple approach has already been used to assess the impact of the 2013 Labor Day Weekend bridge closures<\/a> on Bay Area traffic emissions.<\/p>\n

\"\"<\/a>
\nGetting highly detailed data through a network of low-cost sensors.<\/span>
\nAlexis Shusterman<\/span>, Author provided<\/span><\/span>
\n<\/figcaption><\/figure>\n

While individual nodes can perceive changes in CO2 as small as eight molecules out of a million, when used together, they are even more sensitive. Collectively, BEACO\u2082N\u2019s high-resolution data set can drive complex atmospheric models<\/a> that zero in on still subtler emission phenomena, like the CO2 wafting from a congested freeway during rush hour or a drafty home in wintertime.<\/p>\n

Such analyses will give local lawmakers the facts and figures to critically assess individual line items on California\u2019s 73-part climate action plan<\/a>. Communities can then focus resources on the most effective emissions-reducing initiatives.<\/p>\n

Not just CO2<\/h2>\n

These days, BEACO\u2082N also serves as a pilot platform for testing other low-cost sensing technologies<\/a>.<\/p>\n

While CO2 generally isn\u2019t harmful to breathe, it comes with co-emitted pollutants, like carbon monoxide<\/a> or soot particles<\/a>, that cause asthma and cardiovascular problems. As equipment for measuring these other species comes to market<\/a>, BEACO\u2082N could provide citizens with their own highly localized, real-time air quality<\/em> data as well.<\/p>\n

\"\"<\/a>
\nInside a BEACO\u2082N node.<\/span>
\nAlexis Shusterman<\/span>, Author provided<\/span><\/span>
\n<\/figcaption><\/figure>\n

The first generation of measurements is already being analyzed by research scientists and high schoolers alike, and the data set continues to grow. Since its inception in 2012, the active network has expanded into San Francisco and Sonoma County, with interested parties as far away at Sydney, Australia.<\/p>\n

That\u2019s not to say that the BEACO\u2082N approach is without its own unique challenges. With cheaper equipment, you get what you pay for, namely: drift in the accuracy<\/a> of your data over time. Dust collects on lenses, mirrors get jostled out of alignment, and these small changes can gradually invalidate the original factory calibration.<\/p>\n

High-end instruments<\/a> combat this drift with bulky tanks of \u201creference\u201d gases or pricey proprietary parts, both of which are incompatible with doing science on a budget. It can be just as expensive and time-consuming, however, to repeatedly cycle cheaper instruments back to the lab for recalibration.<\/p>\n

To improve accuracy, the BEACO\u2082N team is currently investigating ways to remotely cross-reference veteran nodes against more recently calibrated ones. BEACO\u2082N may one day be able to use natural phenomena, such as large gusts of wind, to synchronize the signals across long distances.<\/p>\n

By finding ways to do more with less, it is hoped that BEACO\u2082N can pave the way for similar strategies to be adopted by developing nations, or even by curious citizen groups<\/a> here in the US.<\/p>\n

Data produced affordably and accessibly means more knowledge for more people. And when it comes to managing emission reductions, knowledge is power.<\/p>\n

\"The<\/p>\n

Alexis Shusterman<\/a> is PhD candidate in chemistry at University of California, Berkeley<\/a>.<\/p>\n

This article was originally published on The Conversation<\/a>.
\nRead the original article<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

Alexis Shusterman, University of California, Berkeley Earlier this summer, climate change was once again thrust into the global limelight, this time by an unlikely source \u2013 the pope. In his 184-page On Care for Our Common Home, Pope Francis warned: \u201cA very solid scientific consensus indicates that we are presently witnessing a disturbing warming of […]<\/p>\n","protected":false},"author":40,"featured_media":4006,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[118],"tags":[],"_links":{"self":[{"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/posts\/4005"}],"collection":[{"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/users\/40"}],"replies":[{"embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/comments?post=4005"}],"version-history":[{"count":1,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/posts\/4005\/revisions"}],"predecessor-version":[{"id":4007,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/posts\/4005\/revisions\/4007"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/media\/4006"}],"wp:attachment":[{"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/media?parent=4005"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/categories?post=4005"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/tags?post=4005"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}