نتایج جستجو برای: ozone precursors
تعداد نتایج: 59104 فیلتر نتایج به سال:
• Diesel exhaust contains ozone precursors, benzene, arsenic, dioxins, formaldehyde and other toxic substances and is a significant contributor to airborne concentrations of fine particulate matter (PM). Significant health impacts including lung damage and premature death are associated with exposure to fine particulate matter. It can also aggravate conditions such as asthma and bronchitis. Die...
[1] Nitrogen oxide radicals (NOx) produced by lightning are natural precursors for the production of the dominant tropospheric oxidants, OH and ozone. Observations of the interannual variability (IAV) of tropical ozone and of global mean OH (from the methyl chloroform proxy) offer a window for understanding the sensitivity of ozone and OH to environmental factors. We present the results of simu...
As precursors to tropospheric ozone and nitrate, nitrogen oxide (NOx) in the present atmosphere and its transformation in response to emission and climate perturbations are studied by using the CAM-Chem model and air quality measurements from the National Emissions Inventory (NEI), Clean Air Status and Trends Network (CASTNET), and Environmental Protection Agency Air Quality System (EPA AQS). I...
The structural and electronic properties of HfO2 thin films grown by atomic layer deposition (ALD) under various ozone concentrations were investigated using X-ray diffraction (XRD), photoemission (XPS), reflectometry (XRR), and absorption spectroscopy (XAS) and their fine structure (XAFS) analysis. It was found that in the as-grown states, the oxygen stoichiometry and local atomic structure in...
Correlations between surface ozone and meteorological variables exhibit a north-south gradient over the Eastern United States (US), with the ozoneetemperature correlation weakening and the ozoneehumidity correlation transitioning from positive to negative south of 37 N. Using 17 years of hourly August ozone, nitrogen oxide, and isoprene measurements from the Environmental Protection Agency’s Ai...
Ozone concentrations in the Po Valley of northern Italy often exceed international regulations. As both a source of radicals and an intermediate in the oxidation of most volatile organic compounds (VOCs), formaldehyde (HCHO) is a useful tracer for the oxidative processing of hydrocarbons that leads to ozone production. We investigate the sources of HCHO in the Po Valley using vertical profile m...
The oral cavity appears as an open ecosystem, with a dynamic balance between the entrances of microorganisms, colonization modalities, and host defenses aimed to their removal. Gingival and Periodontal diseases represent a major concern both in dentistry and medicine. The oral biofilm formation and development, and the inside selection of specific microorganisms have been correlated with the mo...
Unexpected fast radical production emerges in cool seasons: implications for ozone pollution control
Ozone is a crucial air pollutant that damages human health and vegetation. As it related to the photo-oxidation of nitrogen oxides volatile organic compounds, summertime reduction these precursors primary focus current ozone mitigation strategies. During pollution episodes in eastern China, an observed accumulation daily total oxidants (Ox=NO2+O3</sub...
Regulatory air quality models, such as the Community Multiscale Air Quality model (CMAQ), are used by federal and state agencies to guide policy decisions that determine how to best achieve adherence with National Ambient Air Quality Standards for surface ozone. We use observations of ozone and its important precursor NO2 to test the representation of the photochemistry and emission of ozone pr...
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