Nav: Home

Satellite observations show shifting trends in nitrogen oxide lifetimes over North American cities

November 07, 2019

The new ability to measure NOx lifetime alongside concentration is crucial to understanding the relationship between the two nonlinear factors as well as in gauging how air quality in urban areas will change in response to emission reductions. Thus, say the authors, their analysis holds implications for future efforts to control pollution. Its results may also help to reconcile conflicting trends in NOx emissions estimates; accounting for changes in NOx lifetime is necessary to correctly interpret the relationship between changing NOx emissions and concentrations. Nitrogen oxides - namely nitric oxide and nitrogen dioxide - are powerful pollutants and play an important role in controlling air quality. The highly reactive gases often belched from motor vehicle engines and industrial processes are largely responsible for acid rain and intense air pollution, including the formation of atmospheric particulate matter and ground-level ozone, all of which poorly affect the health of plants and humans. As a result, many nations worldwide have implemented NOx emission standards and technologies to combat air pollution. However, the critical variables involved - NOx concentration and its lifetime in the urban air - share a difficult-to-interpret nonlinear relationship, which can be made more complicated by the chemistry occurring within the plume. Joshua Laughner and Ronald Cohen used daily satellite observations from the Berkeley High Resolution NO2 product to directly measure changes in NOx lifetimes in 34 cities from 2005-2014. Laughner and Cohen suggest that all sampled cities entered what is known as a "NOx -limited chemical regime" - in which NOx lifetime decreases even as NOx concentrations increase - by 2013. The results show that NOx lifetime changes need to be accounted for when relating NOx emissions and concentrations; ignoring these changes could lead to under- or over- estimates of NOx emissions. Fully understanding the factors driving NOx lifetime, though, will require new techniques, the authors say.

American Association for the Advancement of Science

Related Nitrogen Articles:

Reducing reliance on nitrogen fertilizers with biological nitrogen fixation
Crop yields have increased substantially over the past decades, occurring alongside the increasing use of nitrogen fertilizer.
Flushing nitrogen from seawater-based toilets
With about half the world's population living close to the coast, using seawater to flush toilets could be possible with a salt-tolerant bacterium.
We must wake up to devastating impact of nitrogen, say scientists
More than 150 top international scientists are calling on the world to take urgent action on nitrogen pollution, to tackle the widespread harm it is causing to humans, wildlife and the planet.
How nitrogen-fixing bacteria sense iron
New research reveals how nitrogen-fixing bacteria sense iron - an essential but deadly micronutrient.
Corals take control of nitrogen recycling
Corals use sugar from their symbiotic algal partners to control them by recycling nitrogen from their own ammonium waste.
Foraging for nitrogen
As sessile organisms, plants rely on their ability to adapt the development and growth of their roots in response to changing nutrient conditions.
Inert nitrogen forced to react with itself
Direct coupling of two molecules of nitrogen: chemists from Würzburg and Frankfurt have achieved what was thought to be impossible.
Researchers discover new nitrogen source in Arctic
Scientists have revealed that the partnership between an alga and bacteria is making the essential element nitrogen newly available in the Arctic Ocean.
Scientists reveal impacts of anthropogenic nitrogen discharge on nitrogen transport in global rivers
Scientists found that riverine dissolved inorganic nitrogen in the USA has increased primarily due to the use of nitrogen fertilizers.
Nitrogen gets in the fast lane for chemical synthesis
A new one-step method discovered by synthetic organic chemists at Rice University allows nitrogen atoms to be added to precursor compounds used in the design and manufacture of drugs, pesticides, fertilizers and other products.
More Nitrogen News and Nitrogen Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at