PubMed · 3508456
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
E M Johnson. 1987. Developmental toxicity guidelines critique.. https://doi.org/10.1080/08940630.1987.10466266
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Chloroform (CHCl3) is a short-lived ozone-depleting substance not currently regulated under the Montreal Protocol. Due to the unique meteorological conditions in East Asia, CHCl3 emitted in this region has a greater potential to reach the stratosphere and contribute to ozone depletion. As an essential component of national CHCl3 emissions, southeastern China has attracted increasing attention. However, long-term observational data in this region remain relatively scarce, with no updates since 2020. In this study, we continuously measured atmospheric CHCl3 concentrations at a remote monitoring station in southeastern China from 1 June 2023 to 31 May 2025. Frequent concentration enhancements were observed during the monitoring period, with mixing ratios ranging from 9.3 to 134.1 ppt and an average value of 36.8 ± 19.7 ppt. Back-trajectory analysis indicated that air masses associated with elevated CHCl3 levels primarily originated from coastal industrial provinces in eastern China. Using the Potential Source Contribution Function and Concentration Weighted Trajectory methods, we identified the Yangtze River Delta (Jiangsu, Anhui, and Zhejiang Provinces) and Jiangxi Province as dominant source regions. Emissions of CHCl3 in southeastern China were estimated using the Tracer Ratio Method to be approximately 30.1 ± 5.3 Gg/yr from 2023-06-01 to 2025-05-31, indicating overall stability relative to earlier estimates and no apparent upward trend. These findings provide updated insights into the current status of CHCl3 emissions in southeastern China and highlight the need for continued monitoring and emission assessment of CHCl3 in East Asia, given its unregulated status and implications for ozone layer recovery.
An experimental technique was developed for measuring gaseous emissions including ammonia (NH(3)), nitrous oxide (N(2)O) and methane (CH(4)) from broiler houses. This technique included the monitoring of the air flow rate and the gaseous concentrations. NH(3) was determined using acid trap while N(2)O and CH(4) were determined continuously by infrared gas analyser and sequentially by gas chromatography. Moreover, N(2)O and CH(4) emissions were monitored above the litter using closed flux chambers at the end of the experiment. No emissions of N(2)O and CH(4) were observed neither during the growth of the broiler nor above the litter at the end of the experiment. Ammonia concentration varied between 0.8 and 32 ppm in the building. Total ammonia emissions were estimated to 5.74 g N animal(-1) during this experiment. According to this result, ammonia emissions from broiler houses could be estimated to 5.3 kt of N per year in France.
The presence of polycyclic aromatic hydrocarbons (PAHs) in an urban region (Heraklion, Greece) and processes that govern their atmospheric fate were studied from November 2000 until February 2002. Sixteen samples were collected, by using an artifact-free sampling device, on a monthly basis and the concentration of PAHs in gas and particulate phase was determined. The most abundant members (gas + particles) were phenanthrene (20.0+/-7.0 ng m(-3)), fluoranthene (6.5+/-1.7 ng m(-3)), pyrene (6.6+/-2.4 ng m(-3)), and chrysene (3.1+/-1.5 ng m(-3)). Total concentration (gas+particulate) of PAH ranged from 44.3 to 129.2 ng m(-3), with a mean concentration of 79.3 ng m(-3). Total concentration of PAHs in gas phase ranged from 31.4 to 84.7 ng m(-3) with non-observable seasonal variation. Conversely, maximum PAH concentrations in the particulate phase occurred during winter months. Particulate concentration varied from 11.4 to 44.9 ng m(-3), with an average of 25.2 ng m(-3). PAH distribution between gas and particulate phase was in agreement with the sub-cooled vapor pressure. Shift in gas/particle distribution due to difference in ambient temperature elucidated to some extent the seasonal variation of the concentration of PAHs in particles.