Abstract.Beijing is a megacity situated in the rapidly developing Beijing-Tianjin-Hebei region of northern China. In this study, we analyze data on ozone and nitrogen oxide levels obtained at six urban sites in Beijing between the months of July and September. Our goal is to investigate average trends and interpretations over the 2001-2006 period. Average concentrations of NO x (NO x =NO+NO 2 ), O 3 , and O x (O x =O 3 +NO 2 ) were 49.2±5.9 ppbv, 26.6±2.8 ppbv, and 60.3±1.9 ppbv, respectively. NO x concentrations decreased linearly at a rate of 3.9±0.5 ppbv/yr after 2002, while ozone concentrations increased at a rate of 1.1±0.5 ppbv/yr during 2001-2006, and O x concentrations remained nearly constant. The reduction of NO x emissions and elevated non-methane hydrocarbon (NMHCs) emissions may have contributed to the increased O 3 concentrations in Beijing. When the contributions from Beijing's urban and surrounding areas were disaggregated via trajectory cluster analysis, daily maximum and average O x concentrations attributable to Beijing's local emissions increased linearly at rates of 1.3±0.6 ppbv/yr and 0.8±0.6 ppbv/yr, while the O x concentrations attributable to regional areas decreased linearly at rates of 0.6±0.3 ppbv/yr and 0.5±0.3 ppbv/yr, respectively. The decrease in O x concentrations of the surrounding areas was found to counteract increasing Beijing urban O x production, leading to nearly constant O x concentrations in the Beijing region over the study period. Our results may be helpful for redefining government strategies to control the photochemical formation of air pollutants in the Beijing region. Our conclusions have relevance for developing megacities worldwide.
Patients with aggressive periodontitis have significantly elevated levels of plasma C-reactive protein and interleukin-6. These elevated inflammatory factors might potentially increase the risk for cardiovascular events and glucose dysregulation in relatively young individuals.
Patients with AgP may have elevated peripheral leukocyte numbers and serum globulin levels as well as decreased serum albumin levels and albumin/globulin ratios compared to controls. These changes might be associated with the severity of periodontal destruction.
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