But the new findings -- which have implications for petrochemical-producing cities around the world -- come with a catch, says a team of scientists from the Cooperative Institute for Research in Environmental Sciences, or CIRES, a joint institute of the University of Colorado at Boulder and the National Oceanic and Atmospheric Administration.
The problem is that industry still significantly underestimates the amounts of reactive chemicals being released into the air, according to airplane measurements made by the research team as part of the study. Inaccuracies in the reporting of emissions pose big challenges for the reduction and regulation of emissions coming from petrochemical plants. The emissions are important to monitor, because some chemicals released from the plants react to form ground-level ozone that can be harmful to human health and agricultural crops.
"Emissions may have decreased some, but there's still a long way to go," said study author Joost de Gouw, a CIRES atmospheric scientist. "And the emission inventories by industry were not any better in 2006 than they were in 2000."
States that regularly suffer from ozone problems like Texas are required by the federal government to scientifically model what happens during air pollution episodes and develop plans for mitigation. For that to happen effectively, modelers need good inventories, says the research team.
"Initial inventories are not based on measurements. They're based on estimates," said de Gouw. "When you go back to verify those estimates, we find they're not very accurate."
To check on those estimates, lead study author Rebecca Washenfelder of NOAA's Earth System Research Laboratory and CIRES, along with de Gouw, took to the plumes in an aircraft, the NOAA WP-3D, outfitted with an array of air quality measuring instruments. The plane flew through emissions over Houston as part of the second Texas Air Quality Study in 2006, sampling air for signs of ingredients of the chemical reaction that makes ozone, including nitrogen oxides and reactive hydrocarbons.
Washenfelder, de Gouw and their study colleagues compared these measurements with data taken during similar flyovers from the first Texas Air Quality Study in 2000 and another flight in 2002. They then compared those measurements against emissions inventories for each year. In all cases, the industry-reported inventories -- which are supplied to the U.S. Environmental Protection Agency -- didn't agree with the measured amounts of pollutants.
The conflicting data is likely a problem of estimation and general industry practice. "There are tens of thousands of valves and fittings installed throughout the plants in most cases with an assumed -- not measured -- leak rate for each," Washenfelder said.
But industry is taking steps to lessen ozone-causing emissions, and repairs to petrochemical plants may have contributed to recent emission declines. Washenfelder and de Gouw found that the concentrations of ethene and propene -- which both contribute to ozone formation -- dropped by 52 percent and 48 percent respectively between 2000 and 2006.
The two scientists see the study as a wake-up call for emissions monitoring.
"There are a lot of discussions with the petrochemical industry on how to measure these things instead of relying on estimates," said de Gouw. "I think the No. 1 issue here is awareness. As soon as industry is aware that there could be emissions problems down the road, they can figure out how to fix them at lower cost."
The study been accepted for publication in the Journal of Geophysical Research – Atmospheres, a publication of the American Geophysical Union. Funding for the project came from NOAA Air Quality, NOAA Climate Research and Modeling Program, the Texas Commission on Environmental Quality and a National Research Council Postdoctoral Fellowship.
A podcast on the study can be heard at http://colorado.edu/news/podcasts/.
Rebecca Washenfelder | EurekAlert!
Novel method for investigating pore geometry in rocks
18.06.2018 | Kyushu University, I2CNER
Decades of satellite monitoring reveal Antarctic ice loss
14.06.2018 | University of Maryland
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
Light detection and control lies at the heart of many modern device applications, such as smartphone cameras. Using graphene as a light-sensitive material for...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
19.06.2018 | Physics and Astronomy
19.06.2018 | Life Sciences
19.06.2018 | Physics and Astronomy