Ground-level ozone (O3) pollution has been steadily
getting worse in most parts of eastern China during the past 5 years. The
non-linearity of O3 formation with its precursors like nitrogen oxides
...(NOx= NO + NO2) and volatile organic compounds (VOCs) are
complicating effective O3 abatement plans. The diagnosis from
space-based observations, i.e. the ratio of formaldehyde (HCHO) columns to
tropospheric NO2 columns (HCHO / NO2), has previously been proved to
be highly consistent with our current understanding of surface O3
chemistry. HCHO / NO2 ratio thresholds distinguishing O3 formation
sensitivity depend on regions and O3 chemistry interactions with
aerosol. To shed more light on the current O3 formation sensitivity
over China, we have derived HCHO / NO2 ratio thresholds by directly
connecting satellite-based HCHO / NO2 observations and ground-based
O3 measurements over the major Chinese cities in this study. We find
that a VOC-limited regime occurs for HCHO / NO2 < 2.3, and
a NOx-limited regime occurs for HCHO / NO2 > 4.2. The
HCHO / NO2 between 2.3 and 4.2 reflects the transition between the two
regimes. Our method shows that the O3 formation sensitivity tends to be
VOC-limited over urban areas and NOx-limited over rural and remote
areas in China. We find that there is a shift in some cities from the
VOC-limited regime to the transitional regime that is associated with a rapid drop
in anthropogenic NOx emissions, owing to the widely applied rigorous
emission control strategies between 2016 and 2019. This detected spatial
expansion of the transitional regime is supported by rising surface O3
concentrations. The enhanced O3 concentrations in urban areas during
the COVID-19 lockdown in China indicate that a protocol with simultaneous
anthropogenic NOx emissions and VOC emissions controls is essential for
O3 abatement plans.
Air quality observations by satellite instruments are global and have a regular temporal resolution, which makes them very useful in studying long-term trends in atmospheric species. To monitor air ...quality trends in China for the period 2005-2015, we derive SO2 columns and NOx emissions on a provincial level with improved accuracy. To put these trends into perspective they are compared with public data on energy consumption and the environmental policies of China. We distinguish the effect of air quality regulations from economic growth by comparing them relatively to fossil fuel consumption. Pollutant levels, per unit of fossil fuel, are used to assess the effectiveness of air quality regulations. We note that the desulfurization regulations enforced in 2005-2006 only had a significant effect in the years 2008-2009, when a much stricter control of the actual use of the installations began. For national NOx emissions a distinct decreasing trend is only visible from 2012 onwards, but the emission peak year differs from province to province. Unlike SO2, emissions of NOx are highly related to traffic. Furthermore, regulations for NOx emissions are partly decided on a provincial level. The last 3 years show a reduction both in SO2 and NOx emissions per fossil fuel unit, since the authorities have implemented several new environmental regulations. Despite an increasing fossil fuel consumption and a growing transport sector, the effects of air quality policy in China are clearly visible. Without the air quality regulations the concentration of SO2 would be about 2.5 times higher and the NO2 concentrations would be at least 25% higher than they are today in China.
Aims/hypothesis
The study investigated cross-sectional associations of total amount and patterns of sedentary behaviour with glucose metabolism status and the metabolic syndrome.
Methods
We included ...2,497 participants (mean age 60.0 ± 8.1 years, 52% men) from The Maastricht Study who were asked to wear an activPAL accelerometer 24 h/day for 8 consecutive days. We calculated the daily amount of sedentary time, daily number of sedentary breaks and prolonged sedentary bouts (≥30 min), and the average duration of the sedentary bouts. To determine glucose metabolism status, participants underwent an oral glucose tolerance test. Associations of sedentary behaviour variables with glucose metabolism status and the metabolic syndrome were examined using multinomial logistic regression analyses.
Results
Overall, 1,395 (55.9%) participants had normal glucose metabolism, 388 (15.5%) had impaired glucose metabolism and 714 (28.6%) had type 2 diabetes. The odds ratio per additional hour of sedentary time was 1.22 (95% CI 1.13, 1.32) for type 2 diabetes and 1.39 (1.27, 1.53) for the metabolic syndrome. No significant or only weak associations were seen for the number of sedentary breaks, number of prolonged sedentary bouts or average bout duration with either glucose metabolism status or the metabolic syndrome.
Conclusions/interpretation
An extra hour of sedentary time was associated with a 22% increased odds for type 2 diabetes and a 39% increased odds for the metabolic syndrome. The pattern in which sedentary time was accumulated was weakly associated with the presence of the metabolic syndrome. These results suggest that sedentary behaviour may play a significant role in the development and prevention of type 2 diabetes, although longitudinal studies are needed to confirm our findings.
We present a 3-D climatology of the desert dust distribution over
South and East Asia derived using CALIPSO (Cloud-Aerosol Lidar and
Infrared Pathfinder Satellite Observation) data. To distinguish
...desert dust from total aerosol load we apply a methodology developed
in the framework of EARLINET (European Aerosol Research Lidar
Network). The method involves the use of the particle linear
depolarization ratio and updated lidar ratio values suitable for
Asian dust, applied to multiyear CALIPSO observations
(January 2007–December 2015). The resulting dust product provides information
on the horizontal and vertical distribution of dust aerosols over
South and East Asia along with the seasonal transition of dust
transport pathways. Persistent high D_AOD (dust aerosol optical depth) values at 532 nm, of the order of 0.6, are present
over the arid and semi-arid desert regions. Dust aerosol transport
(range, height and intensity) is subject to high seasonality, with the highest values observed during spring for northern China
(Taklimakan and Gobi deserts) and during summer over the Indian
subcontinent (Thar Desert). Additionally, we decompose the CALIPSO
AOD (aerosol optical depth) into dust and non-dust aerosol
components to reveal the non-dust AOD over the highly industrialized
and densely populated regions of South and East Asia, where the
non-dust aerosols yield AOD values of the order of 0.5. Furthermore,
the CALIPSO-based short-term AOD and D_AOD time series and trends
between January 2007 and December 2015 are calculated over South and East Asia
and over selected subregions. Positive trends are observed over
northwest and east China and the Indian subcontinent, whereas over
southeast China trends are mostly negative. The calculated AOD
trends agree well with the trends derived from Aqua MODIS (Moderate
Resolution Imaging Spectroradiometer), although significant
differences are observed over specific regions.
Global observations of tropospheric nitrogen dioxide (NO2) columns have been shown to be feasible from space, but consistent multi-sensor records do not yet exist, nor are they covered by planned ...activities at the international level. Harmonised, multi-decadal records of NO2 columns and their associated uncertainties can provide crucial information on how the emissions and concentrations of nitrogen oxides evolve over time. Here we describe the development of a new, community best-practice NO2 retrieval algorithm based on a synthesis of existing approaches. Detailed comparisons of these approaches led us to implement an enhanced spectral fitting method for NO2, a 1∘ × 1∘ TM5-MP data assimilation scheme to estimate the stratospheric background and improve air mass factor calculations. Guided by the needs expressed by data users, producers, and WMO GCOS guidelines, we incorporated detailed per-pixel uncertainty information in the data product, along with easily traceable information on the relevant quality aspects of the retrieval. We applied the improved QA4ECV NO2 algorithm to the most current level-1 data sets to produce a complete 22-year data record that includes GOME (1995–2003), SCIAMACHY (2002–2012), GOME-2(A) (2007 onwards) and OMI (2004 onwards). The QA4ECV NO2 spectral fitting recommendations and TM5-MP stratospheric column and air mass factor approach are currently also applied to S5P-TROPOMI. The uncertainties in the QA4ECV tropospheric NO2 columns amount to typically 40 % over polluted scenes. The first validation results of the QA4ECV OMI NO2 columns and their uncertainties over Tai'an, China, in June 2006 suggest a small bias (-2 %) and better precision than suggested by uncertainty propagation. We conclude that our improved QA4ECV NO2 long-term data record is providing valuable information to quantitatively constrain emissions, deposition, and trends in nitrogen oxides on a global scale.
Tropospheric nitrogen dioxide (NO2) column densities detected from space are widely used to infer trends in terrestrial nitrogen oxide (NO x ) emissions. We study changes in NO2 column densities ...using the Ozone Monitoring Instrument (OMI) over China from 2005 to 2015 and compare them with the bottom-up inventory to examine NO x emission trends and their driving forces. From OMI measurements we detect the peak of NO2 column densities at a national level in the year 2011, with average NO2 column densities deceasing by 32% from 2011 to 2015 and corresponding to a simultaneous decline of 21% in bottom-up emission estimates. A significant variation in the peak year of NO2 column densities over regions is observed. Because of the reasonable agreement between the peak year of NO2 columns and the start of deployment of denitration devices, we conclude that power plants are the primary contributor to the NO2 decline, which is further supported by the emission reduction of 56% from the power sector in the bottom-up emission inventory associated with the penetration of selective catalytic reduction (SCR) increasing from 18% to 86% during 2011–2015. Meanwhile, regulations for vehicles also make a significant contribution to NO x emission reductions, in particular for a few urbanized regions (e.g., Beijing and Shanghai), where they implemented strict regulations for vehicle emissions years before the national schedule for SCR installations and thus reached their NO2 peak 2–3 years ahead of the deployment of denitration devices for power plants.
The Maastricht Study is an extensive phenotyping study that focuses on the etiology of type 2 diabetes (T2DM), its classic complications, and its emerging comorbidities. The study uses ...state-of-the-art imaging techniques and extensive biobanking to determine health status in a population-based cohort of 10,000 individuals that is enriched with T2DM individuals. Enrollment started in November 2010 and is anticipated to last 5-7 years. The Maastricht Study is expected to become one of the most extensive phenotyping studies in both the general population and T2DM participants worldwide. The Maastricht study will specifically focus on possible mechanisms that may explain why T2DM accelerates the development and progression of classic complications, such as cardiovascular disease, retinopathy, neuropathy and nephropathy and of emerging comorbidities, such as cognitive decline, depression, and gastrointestinal, musculoskeletal and respiratory diseases. In addition, it will also examine the association of these variables with quality of life and use of health care resources. This paper describes the rationale, overall study design, recruitment strategy and methods of basic measurements, and gives an overview of all measurements that are performed within The Maastricht Study.
Satellite nitrogen dioxide (NO2) observations have been widely used to evaluate emission changes. To determine trends in nitrogen oxides (NOx) emission over China, we used a method independent of ...chemical transport models to quantify the NOx emissions from 48 cities and seven power plants over China, on the basis of Ozone Monitoring Instrument (OMI) NO2 observations from 2005 to 2015. We found that NOx emissions over 48 Chinese cities increased by 52 % from 2005 to 2011 and decreased by 21 % from 2011 to 2015. The decrease since 2011 could be mainly attributed to emission control measures in power sector; while cities with different dominant emission sources (i.e., power, industrial, and transportation sectors) showed variable emission decline timelines that corresponded to the schedules for emission control in different sectors. The time series of the derived NOx emissions was consistent with the bottom-up emission inventories for all power plants (r = 0. 8 on average), but not for some cities (r = 0. 4 on average). The lack of consistency observed for cities was most probably due to the high uncertainty of bottom-up urban emissions used in this study, which were derived from downscaling the regional-based emission data to city level by using spatial distribution proxies.
Chronic kidney disease, which is defined as having a reduced kidney function (estimated glomerular filtration rate (eGFR)) and/or signs of kidney damage (albuminuria), is highly prevalent in Western ...society and is associated with adverse health outcomes, such as cardiovascular disease. This warrants a search for risk factors of lower eGFR and higher albuminuria. Physical activity and sedentary behavior may be such risk factors.
To examine associations of physical activity (total, high, low), sedentary time and sedentary behavior patterns (breaks, prolonged bouts, average bout duration) with eGFR and albuminuria.
We examined these associations in 2,258 participants of the Maastricht Study (average age 60.1±8.1 years; 51.3% men), who wore an accelerometer 24h/day on 7 consecutive days. Associations with continuous eGFR and categories of urinary albumin excretion (UAE; <15 reference category, 15-<30, ≥30 mg/24h) were evaluated with linear regression analyses and multinomial logistic regression analyses, respectively.
After adjustment for potential confounders, each extra hour of total physical activity was associated with a more favorable kidney function (betaeGFR = 2.30 (95%CI = 1.46; 3.14)), whereas each extra hour of sedentary behavior was associated with a more adverse kidney function (betaeGFR = -0.71 (-1.08; -0.35)). Also, compared to individuals with the lowest levels of total physical activity, individuals with the highest levels had less kidney damage (OR15-<30mg/24h = 0.63 (0.41; 0.96), OR≥30mg/24h = 0.84 (0.53; 1.35). An extra hour of sedentary behavior was associated with more kidney damage (OR15-<30 mg/24h = 1.11 (1.01; 1.22), OR≥30 mg/24h = 1.10 (0.99; 1.22)). Further, a highly sedentary pattern was associated with a more adverse kidney function, but no association was seen with kidney damage.
Physical activity and sedentary behavior were associated with kidney function and kidney damage. Additionally, sedentary behavior patterns were associated with kidney function. Causal studies are required to examine whether this indeed implicates that prevention strategies should focus not only on increasing physical activity, but on reducing sedentary behavior as well.
PDF
