What is Emissions: Definition and 65 Discussions

Emissions trading (also known as cap and trade, emissions trading scheme or ETS) is a market-based approach to controlling pollution by providing economic incentives for reducing the emissions of pollutants.A central authority (usually a governmental body) allocates or sells a limited number of permits that allow a discharge of a specific quantity of a specific pollutant over a set time period. Polluters are required to hold permits in amount equal to their emissions. Polluters that want to increase their emissions must buy permits from others willing to sell them.Cap and trade (CAT) programs are a type of flexible environmental regulation that allows organizations and markets to decide how best to meet policy targets. This is in contrast to command-and-control environmental regulations (such as best available technology (BAT) standards and government subsidies).
A 2020 study found that the European Union Emissions Trading System successfully reduced CO2 emissions even though the prices for carbon were set at low prices.

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  1. nsaspook

    Cummins rigged about 1 million Ram pickup trucks to cheat emissions

    Some people just don't learn. The VW type software cheat continues. https://www.justice.gov/opa/pr/united-states-and-california-announce-diesel-engine-manufacturer-cummins-inc-agrees-pay https://www.thecooldown.com/green-business/cummins-truck-emissions-justice-department-fine/ COMPANY FINED...
  2. Astronuc

    The Future of Rocket Propulsion, What To Do About Emissions

  3. M

    B CO2 Emissions, Gas Vs Electric

    I read that a kg of gas provides about 13kWh (47.5MJ) of energy and that burning a kg of gas emits about 3.15 kg of CO2. So presumably a gas-powered engine emits 3.15/13 or about .242kg of CO2 per kWh of work, right? According to the EIA, the US electric grid emits about 0.85lb or 0.386kg of...
  4. greg_rack

    Isotope decay via alpha and beta particle emissions

    This problem really confused me, since I can't get the link between particles emitted(alpha and beta, but which are the differences between those?) and changes in mass and atomic number of the isotope. For this one, I can't really show you my attempt since there ain't one...
  5. G

    Negative carbon emissions to fight ocean acidification?

    The IPCC report strongly encouraged not only trying to get our carbon dioxide emissions down to fight climate change, but to go into negative emissions so as to draw the carbon dioxide out of the air (since it's too high as it is). Wouldn't that help to fight ocean acidification too? Because...
  6. C

    Carbon sequestration, how does it work? Is it practical?

    Hi All, I understand carbon sequestration in the simplest sense is capturing and storing carbon. As seen in the title, I'm going to split this into two sections. i) How does it work? I imagine that trees, in a sense are doing this. They take in the carbon from our atmosphere and is stored...
  7. Nik_2213

    China's diffuse chloro-carbon emissions?

    IIRC, the hunt is on for the elusive source of China's diffuse halo-carbon emissions. May I offer their busy faux-leather industry, based around 'vinyl' & 'PVC' materials ? Personal observation: Family member ordered a bespoke pair of smart 'party boots' from a AliEx company. When those arrived...
  8. H

    Using moss to combat CO2 emissions

    I came across a few different articles and social media post that claim moss is far better at absorbing CO2 and other pollutants then trees. The article from the link below claims that a relatively small planter is the equivalent of 250 trees. Is this accurate? If it is, why isn't this more...
  9. mfb

    B Coal and total CO2 emissions in the UK

    Mentor note: This thread started as side-discussion in the thread New Tokamak D Mode Success - Fusion is Almost Here, see there for earlier posts that lead to this discussion. I split the threads. Everything from post 2 to post 20 was moved, later posts were made here.
  10. Dedale

    New regulations on maritime emissions

    I stumbled on a recent article on the guardian newspaper: https://www.theguardian.com/environment/2018/apr/13/carbon-dioxide-from-ships-at-sea-to-be-regulated-for-first-time I was wondering if that was realistic or just some sort of public relation stint. The regulation set a distant future...
  11. Buzz Bloom

    I Models of accretion disc emissions contradicted by experiment

    Ref: http://www.spaceref.com/news/viewpr.html?pid=51416 I would be very interested to see comments from knowledgeable people about this. My impression is that this is one more example of a need to remain at least somewhat skeptical about theoretical models that have not yet been validated by...
  12. K

    I Why are pollutant emissions measured in g/km?

    When we read about how much carbon dioxide (or any other air pollutant) an internal combustion engine in a certain vehicle produces, the measure unit employed is grams per kilometre, it is, mass per unit of distance. However, in my understanding, it would make much more sense to measure...
  13. P

    Question about light emissions of fluorescent bulbs

    So today I was in one of the rooms in the gym where they have 4 fluorescent lights shining. 2 of them where clearly low on life/power and they were barely glowing, the glow was this very faint pink color. So my friends asked me why I thought they were glowing pink. On the spot I thought of some...
  14. M

    How can we reduce VOC emissions from painting boats

    I am interested in measures to reduce VOC levels in paint on boats in its outdoor or enclosed space
  15. Ali Durrani

    EGR & NOx Emissions: Test Results & Explanation

    Hello i have done tests on Exhaust gas re circulation on my engine test bench and these are the results, i don't know what's wrong? but at 8% loading conditions i am getting some weird results the trendlines in the graph shows an increase in NOx with EGR is there any explanation for this ? thanks
  16. T

    Variations in Emissions Inventories?

    Are there multiple sources for an emissions inventory? For instance, how debated is the UNFCCC GHG inventory? (http://unfccc.int/ghg_data/items/3800.php) And is there any international inventory that has an emissions breakdown like the Australian governments? (http://ageis.climatechange.gov.au/#)
  17. timallard

    Atlantic Inflow to the Arctic Basin via Pacific Inflow

    [screenshot nullschool ocean-currents-ssta] Inflow from the Pacifc the main flow show drifting east and a general value 0.8-0.9 sverdrup containing 10-Tw/winter, 20-Tw/summer heat-flux of less dense water from freshwater runoff creating a head-height of 40-50cm helping to melt sea-ice from...
  18. Hyo X

    Ammoniation of Cattlefeed on Bovine Methane emissions

    Has this study been done? It seems the ammoniation [using ammonium hydroxide] of low-quality straw to increase digestibility of the feedstock is an established practice. Also, cows are a pretty big producer of methane, a significant greenhouse gas. Does treating with ammonium hydroxide the...
  19. T

    Carbon emissions question

    Homework Statement Using the above result, estimate the annual CO2 emission savings (in kg/yr) associated with replacing one 60W incandescent bulb with one 13W fluorescent bulb, in one typical Canadian household. Do this calculation from “first principles” using the following assumptions: (The...
  20. gokhul

    The Sun's Fire: Low O2 and Carbon Emissions

    There is only 0.77% of oxygen in sun And only 0.29% of carbon The question is there is only small amount of o2 but how how sun is surrounded by fire with very less emissions of carbon ( referred to Wikipedia for amount of gas in sun)
  21. nsaspook

    News EPA says Volkswagen installed software to cheat on emissions

    http://www.bloomberg.com/news/articles/2015-09-18/epa-says-volkswagon-software-circumvented-car-emissions-testing http://www3.epa.gov/otaq/cert/documents/vw-nov-caa-09-18-15.pdf This makes me wonder who else is cheating with ECU/ECM software.
  22. Alastair McD

    Can stimulated emissions from CO2 be absorbed?

    When an excited molecule absorbs a photon two coherent photons are emitted. If one of these photons is absorbed by a second molecule, since the emission was coherent then that molecule will absorb the second photon too. If the second molecule was in the ground state then it will become excited...
  23. Jonski

    Energy Intensity of black coal

    Homework Statement Brown coal, energy content 16 MJ/kg, carbon content 65% by weight, burning in a 30% efficient steam power plant. Homework Equations What is the emissions intensity (kg CO2 emitted/kWh delivered) ? Compare this to Hazelwood which is 1.53 tCO2/Mwh 3. The Attempt at a Solution...
  24. UMath1

    Landfill methane gas emissions

    I read that biodegradable waste in landfills produces methane, a harmful GHG. But didn't biodegradable waste always exist? We throw paper away, but the trees we produce paper from would have died eventually. Our organic waste comes from plants and animals that would have died eventually too. So...
  25. O

    Gamma spectrometry: Calibration using X-ray emissions

    I have just done an efficiency calibration measurement for the HPGe detector of a whole-body counter. Ba-133 and Eu-152 were the calibration nuclides. For a calibration at low energies I thought of using the X-ray emissions of both nuclides as well. However, the result looks quite bad - see the...
  26. M

    Understanding Light Beam Emissions and SR's Light Clock

    No matter how many explanations of SR I try to read this honestly really bugs me :-) Perhaps someone here can provide a different perspective that will make it click for me, i don't know... The way I model the problem is thus: A C B there being 2 inertial frames, one for A&B...
  27. jim mcnamara

    Reticulum 2 - gamma ray emissions

    http://arxiv.org/pdf/1503.02320v1.pdf This paper discusses the emission of gamma rays from a neighboring dwarf galaxy. My understanding is that there is no conventional explanation of gamma ray emission. So there is interest in pursuing a possibility that these emissions are from dark matter...
  28. C

    Finding particulate matter emissions

    Homework Statement A power plant burns oil that is 4% ash and 3% Sulfur. At 50% excess air, what particulate (mg/m^3) emissions would you expect? Homework Equations PM in grams = 2.8*.04=.112 grams of PM per 1000 kg of oil Start with 1000 g of oil oil = 4% ash, 3%sulfur, and 93% carbon...
  29. T

    Automotive Average Car Exhaust NOx Emissions with Catalytic Converter Explained

    Can anyone help me out and tell me what the average amount of ppm of NOx is in car exhaust with a catalytic converter? I found .4 grams per mile and can't seem to find any kind of conversion, but I am trying to compare it to another ppm measurement so it needs to be in ppm. Thank you
  30. D

    Fossil Fuels vs. Natural Gas: Carbon Emissions Explained

    Hi there, Could someone explain to me why fossil fuels, such as coal and oil, produce fewer particulate matter emissions than natural gas? Also, how would you expect the combustion temperature of these fuels to affect particulate emissions? Would a higher temperature lead to a more complete...
  31. jim mcnamara

    Dark Matter and X-ray emissions

    This is a video by the two of the researchers who found anomalous xray emissions. These emissions may be related to dark mater, needs further verification. Edit 12/14/14 : preprint http://arxiv.org/abs/1402.4119
  32. Chronos

    Andromeda vs Milky Way dust emissions

    As many are aware, the announced detection of primordial gravity waves by BICEP 2 was heavily criticized based on dust emission modeling. Today, Planck XXV was released which mapped out the dust emissions of Andromeda. Assuming Andromeda is representative of the Milky Way in most relevant ways...
  33. J

    Is it possible to recycle vehicle emissions in order to generate elect

    I’ve been doing some research and thinking recently into how vehicle emissions might be used to generate electricity in order to power the vehicle itself. I’ve seen a few products and research projects centred on this topic, although they all seem to be focused on converting the heat in the...
  34. M

    Total Carbon Dioxide emissions for 2013

    Hello there I've been searching the internet for any information about the total carbon emissions for this year (tonnes/year). However, I've only come across data which is most recently been gather a few years ago (2009 - 2011). However, I'm really curious to what the total emissions are...
  35. W

    Two Laser Emissions: Resolving Contradiction

    I can't figure this out. Say 2 frames are in relative motion. When the origins at at the same place, 2 lasers shoot up the positive x-axis and negative x axis. Let's call the 2 frames F and F'. F says the lasers will always hit simultaneous events along the x-axis. Then by the relativity of...
  36. T

    Comp Sci FORTRAN 90 Tracking cumulative emissions read in as annual emissions from a txt file

    Homework Statement I am attempting to modify an original set of code which uses a spline interpolator to plot a curve representing cumulative emissions (and its derivative annual emissions). The goal is to read in the historical emissions (from histem.txt) and then track the cumulative...
  37. Q

    Radioisotopes: Alpha, Beta, Gamma Emissions?

    I need to question that what does radio isotopes emits?Alpha,Beta,Gamma or all particles?
  38. Demon117

    Exploring Single Photon Emissions in H-Atom: The Mystery of 2s to 1s Transition

    Why is it that for the H-atom there is no single photon emission in the transition from 2s to 1s? I realize that two-photon emission is valid in this transition but why not single-photon emission?
  39. A

    How emissions for a spectra provide evidence for energy levels in a atom?

    Explain how data from emissions spectra provide evidence for discreet energy levels within the atom?
  40. TheStatutoryApe

    Can I get a refund for my used vehicle if it fails emission tests?

    I purchased a used vehicle. When I bought it the CPU had been reset and I was unable to get it smogged (emissions tested). When the CPU finished its cycles I got it tested and it failed. Mechanic said I should replace the EGR Valve and the 1st O2 sensor. I did so and it failed again. Then...
  41. H

    Proving the Visible Emissions of Balmer Series in Hydrogen Atom

    Hello, I don't know if this is the right place to post.. this is a self study question from Levine, it is told that is important but i have no clue in solving it .. The Balmer series corresponds to a set of emissions involving the electron in a hydrogen atom relaxing from a high energy...
  42. J

    Compressed/Uncompressed gas combustion and Emissions

    Hello Maybe this is a question more for chemists but then maybe not... We are talking about burnt emissions pollution in class. Comparing internal combustion engine emissions with household water heating systems (boilers) emissions. Please can anyone tell us if petrol/gasoline internal...
  43. B

    What Happens When a Black Hole Swallows Another Black Hole?

    I just read an article about recently observed jets emitted from a black hole, apparently due to the extreme acceleration of something falling into it. Now I'm wondering what would happen if the object accelerating into the black hole was another black hole. Yes, black holes are expected to...
  44. E

    A good introductory book on acoustic emissions?

    I am looking for an introductory book on sensing using acoustic emissions. Specifically, I am hoping to use acoustic emissions signals to detect tool wear (and classify the wear as mild, severe, etc.). Does anyone have a recommendation? Something with examples using LabView and/or MATLAB...
  45. E

    The Amount of Human CO2 emissions vs. The Scale of our Atmosphere

    My biology teacher asserted to our class that compared to the vastness of the atmosphere of our earth, the amount of harmful gasses we are emitting is a fraction of a percent and therefore can be dismissed as harmless, and instead we should be worrying about more fragile ecosystems down here on...
  46. N

    Carbon Dioxide emissions question

    I've been wondering recently about the air quality in cities. Suppose all cars/transport methods were to go electric or clean (electric cars etc...) how much would air quality improve by? In other words what % of the nitrous oxide and carbon dioxide emissions are mobile sources responsible for...
  47. J

    Comparative GHG Emissions of Coal, Domestic Natural Gas, LNG, and SNG

    You might be interested in this paper: Jaramillo, P., W. M. Griffin, and H.S. Matthews. 2007. Comparative life-cycle air emissions of coal, domestic natural gas, LNG, and SNG for electricity generation. Environmental Science & Technology, Vol. 41, No. 17, 6290-6296 You can download it here...
  48. S

    Human Carbon Dioxide Emissions Reverse 2000 Years of Arctic Cooling

    http://www.ucar.edu/news/releases/2009/arctic2k.jsp [Broken] The associated albedo flip will amplify the warming.
  49. J

    What CO2 Emissions Level Would Stabilize Atmospheric CO2 Level?

    I was reading a new paper titled "Impacts of Climate Change on Marine Organisms and Ecosystems" when I came across this statement: It has been suggested that a CO2[atm] of 450 ppm is a critical threshold beyond which catastrophic and irreversible change might occur [7] this would bring a...