831 research outputs found

    Air quality in and around traffic tunnels

    Get PDF
    The National Health and Medical Research Council (NHMRC), in collaboration with the Department of Health and Ageing, commissioned a systematic review of national and international literature and practices in relation to air quality in and around traffic tunnels. This review formed the basis of a national NHMRC workshop attended by experts from the health and environment sectors, as well as representatives of government agencies and consumer groups. The outcomes of the review, workshop and subsequent submissions were analysed to inform the development of the Air Quality in and around Traffic Tunnels - Final Report. This Report evaluates the factors associated with poor air quality in and around traffic tunnels and the subsequent health effects resulting from exposure to air pollution

    Air quality improvement in response to intensified control strategies in Beijing during 2013–2019

    Get PDF
    Beijing's air pollution has become of increasing concern in recent years. The central and municipal governments have issued a series of laws, regulations, and strategies to improve ambient air quality. The “Clean Air Action” issued in 2013 and the “Comprehensive Action” issued in 2017 largely addressed this concern. In this study, we assessed the effectiveness of the two action plans by environmental monitoring data and evaluated the influencing factors including meteorology, pollutant emissions, and energy structure. The spatial distributions of air pollutants were analyzed using the Kriging interpolation method. The Principal Component Analysis-Multiple Nonlinear Regression (PCA-MNLR) model was applied to estimate the effects of meteorological factors. The results have shown that Beijing's air quality had a measurable improvement over 2013–2019. “Good air quality” days had the highest increases, and “hazardous air quality” days had the most decreases. SO2 decreased most, followed by CO, PM2.5, PM10, and NO2 in descending order, but O3 showed a fluctuant increase. The “Comprehensive Action” was more effective than the “Clean Air Action” in reducing heavy pollution days during the heating period. The meteorological normalized values of the main pollutants were lower than the observation data during 2013–2016. However, the observed values became lower than the normalized values after 2017, which indicated beneficial weather conditions in 2017 and afterwards. The emissions of SO2 and dust significantly decreased while NOx had a slight decrease, and the energy structure changed with a dramatic decrease in coal consumption and an obvious increase in the use of natural gas and electricity. The significant reduction of coal-fired emissions played a dominant role in improving Beijing's air quality, and vehicle emission control should be further enhanced. The results demonstrated the effectiveness of the two action plans and the experience in Beijing should have potential implications for other areas and nations suffering from severe air pollution

    Environmental Science and Technology Department annual report 1990

    Get PDF

    Long-term measurement of sub-3 nm particles and their precursor gases in the boreal forest

    Get PDF
    The knowledge of the dynamics of sub-3 nm particles in the atmosphere is crucial for our understanding of the first steps of atmospheric new particle formation. Therefore, accurate and stable long-term measurements of the smallest atmospheric particles are needed. In this study, we analyzed over 5 years of particle concentrations in size classes 1.1-1.7 and 1.7-2.5 nm obtained with the particle size magnifier (PSM) and 3 years of precursor vapor concentrations measured with the chemical ionization atmospheric pressure interface time-of-flight mass spectrometer (CI-APi-ToF) at the SMEAR II station in Hyytiala, Finland. The results show that there are significant seasonal differences in median concentrations of sub-3 nm particles, but the two size classes behave partly differently. The 1.1-1.7 nm particle concentrations are highest in summer, while the 1.7-2.5 nm particle concentrations are highest in springtime. The 1.7-2.5 nm particles exhibit a daytime maximum in all seasons, while the 1.1-1.7 nm particles have an additional evening maximum during spring and summer. Aerosol precursor vapors have notable diurnal and seasonal differences as well. Sulfuric acid and highly oxygenated organic molecule (HOM) monomer concentrations have clear daytime maxima, while HOM dimers have their maxima during the night. HOM concentrations for both monomers and dimers are the highest during summer and the lowest during winter following the biogenic activity in the surrounding forest. Sulfuric acid concentrations are the highest during spring and summer, with autumn and winter concentrations being 2 to 3 times lower. A correlation analysis between the sub-3 nm concentrations and aerosol precursor vapor concentrations indicates that both HOMs (particularly their dimers) and sulfuric acid play a significant role in new particle formation in the boreal forest. Our analysis also suggests that there might be seasonal differences in new particle formation pathways that need to be investigated further.Peer reviewe

    Role of carbon cycle observations and knowledge in carbon management

    Get PDF
    Author Posting. © Annual Reviews, 2003. This article is posted here by permission of Annual Reviews for personal use, not for redistribution. The definitive version was published in Annual Review of Environment and Resources 28 (2003): 521-558, doi:10.1146/annurev.energy.28.011503.163443.Agriculture and industrial development have led to inadvertent changes in the natural carbon cycle. As a consequence, concentrations of carbon dioxide and other greenhouse gases have increased in the atmosphere and may lead to changes in climate. The current challenge facing society is to develop options for future management of the carbon cycle. A variety of approaches has been suggested: direct reduction of emissions, deliberate manipulation of the natural carbon cycle to enhance sequestration, and capture and isolation of carbon from fossil fuel use. Policy development to date has laid out some of the general principles to which carbon management should adhere. These are summarized as: how much carbon is stored, by what means, and for how long. To successfully manage carbon for climate purposes requires increased understanding of carbon cycle dynamics and improvement in the scientific capabilities available for measurement as well as for policy needs. The specific needs for scientific information to underpin carbon cycle management decisions are not yet broadly known. A stronger dialogue between decision makers and scientists must be developed to foster improved application of scientific knowledge to decisions. This review focuses on the current knowledge of the carbon cycle, carbon measurement capabilities (with an emphasis on the continental scale) and the relevance of carbon cycle science to carbon sequestration goals.The National Center for Atmospheric Research is supported by the National Science Foundation
    • …
    corecore