VOLATILE organic compounds, AEROSOLS (Sprays), EMISSIONS (Air pollution), AIR pollution, SESQUITERPENES, GASES from plants, MONOTERPENES, and ORGANIC chemistry
Biogenic volatiIe organic compounds (BVOC) contribute significantly to the formation of ozone and secondary organic aerosol (SOA). The Model of Emissions of Gases and Aerosols from Nature (MEGANv2.02) is used to estimate emissions of isoprene, monoterpenes (MT), and sesquiterpenes (SQT) across the United States. Compared to the Biogenic Emission Inventory System (BEIS3.0), MEGANv2.02 estimates higher isoprene but lower MT emissions for July 2001 and January 2002. A sensitivity study of SQT and MT emission factors and algorithm parameters was conducted by assigning values to four plant functional types (PFTs) using both recent measurements and literature values. The standard deviations of the emissions factors within these PFTs were two to four times the averages because of the variation in experimental basal emissions rate data. More recently published SQT and MT basal emission rates are generally lower than those reported in the literature through 2004. With the new emissions factors, monthly average SQT emission rates for the contiguous United States are equal to 16% of the MT emissions during July and 9% of the emissions during January. The SQT emissions distribution is strongly influenced by the grass and crop PFT, for which SQT emissions data are quite limited. [ABSTRACT FROM AUTHOR]
CARBON, LIGHT elements, ORGANIC compounds, CARBON compounds, ORGANIC chemistry, AIR quality, ENVIRONMENTAL quality, and AIR pollution
Summertime concentrations of fine particulate carbon in the southeastern United States are consistently underestimated by air quality models. In an effort to understand the cause of this error, the Community Multiscale Air Quality model is instrumented to track primary organic and elemental carbon contributions from fifteen different source categories. The model results are speciated using published source profiles and compared with ambient measurements of 100 organic markers collected at eight sites in the Southeast during the 1999 summer. Results indicate that modeled contributions from vehicle exhaust and biomass combustion, the two largest sources of carbon in the emission inventory, are unbiased across the region. In Atlanta, good model performance for total carbon (TC) is attributed to compensating errors: overestimation of vehicle emissions with underestimations of other sources. In Birmingham, 35% of the TC underestimation can be explained by deficiencies in primary sources. Cigarette smoke and vegetative detritus are not in the inventory, but contribute less than 3% of the IC at each site. After the model results are adjusted for source-specific errors using the organic-marker measurements, an average of 1.6 µgC m-3 remain unexplained. This corresponds to 26-38% of ambient TC concentrations at urban sites and up to 56% at rural sites. The most likely sources of unexplained carbon are discussed. [ABSTRACT FROM AUTHOR]
ORGANIC compounds, SPRAYING & dusting in agriculture, PEST control, BIOTIC communities, ORGANIC chemistry, CORRELATION (Statistics), and FACILITY management
The United States (U.S.) National Park Service has initiated research on the atmospheric deposition and fate of semi-volatile organic compounds in its alpine, sub-Arctic, and Arctic ecosystems in the Western U.S. Results for the analysis of pesticides in seasonal snowpack samples collected in spring 2003 from seven national parks are presented herein. From a target analyte list of 47 pesticides and degradation products, the most frequently detected current-use pesticides were dacthal, chlorpyrifos, endosulfan, and 7-hexachlorocyclohexane, whereas the most frequently detected historic-use pesticides were dieldrin, α-hexachlorocyclohexane, chlordane, and hexachlorobenzene. Correlation analysis with latitude, temperature, elevation, particulate matter, and two indicators of regional pesticide use reveal that regional current and historic agricultural practices are largely responsible for the distribution of pesticides in the national parks in this study. Pesticide deposition in the Alaskan parks is attributed to long-range transport because there are no significant regional pesticide sources. The percentage of total pesticide concentration due to regional transport (%RT) was calculated for the other parks. %RT was highest at parks with higher regional cropland intensity and for pesticides with lower vapor pressures and shorter half-lives in air. [ABSTRACT FROM AUTHOR]
Focuses on the importance of experiments based on the principles of green chemistry in Oregon. Modern reactions in the organic chemistry lab curriculum; Promotion of green chemistry approach by the American Chemical Society; Description of a benign method for synthesizing tetraphenylporphyrin in the textbook by professor James Hutchison. INSET: Green lab experiments..
ENVIRONMENTAL protection, ENVIRONMENTAL law, AUTOMOBILE industry, ORGANIC chemistry, VOLATILE organic compounds, AIR pollution, EMISSIONS (Air pollution), and POLLUTANTS
The article reports on the move initiated by the United State Environmental Protection Agency(U.S. EPA) in the practices of carmakers in painting their automobile while adopting to lower costs and improving the products. In line with the Clean Air Act in the U.S., the U.S. EPA some state agencies regulated volatile organic compounds emitted from paint refinishing at body shops and car dealers, since facilities do not necessarily have emissions-control technologies. It was emphasized that the regulations do not require an update of the technologies unless a plant is to be modified significantly.