scholarly journals Decomposing the Long-term Variation in Population Exposure to Outdoor PM2.5 in the Greater Bay Area of China Using Satellite Observations

2019 ◽  
Vol 11 (22) ◽  
pp. 2646 ◽  
Author(s):  
Changqing Lin ◽  
Alexis K. H. Lau ◽  
Jimmy C. H. Fung ◽  
Qianshan He ◽  
Jun Ma ◽  
...  
Keyword(s):  
City Planning ◽  
Satellite Observations ◽  
Population Exposure ◽  
Exposure Level ◽  
Bay Area ◽  
Spatial Differences ◽  
Exposure Levels ◽  
The Impact ◽  
Pm2.5 Concentration

The Greater Bay Area (GBA) of China is experiencing a high level of exposure to outdoor PM2.5 pollution. The variations in the exposure level are determined by spatiotemporal variations in the PM2.5 concentration and population. To better guide public policies that aim to reduce the population exposure level, it is essential to explicitly decompose and assess the impacts of different factors. This study took advantage of high-resolution satellite observations to characterize the long-term variations in population exposure to outdoor PM2.5 for cities in the GBA region during the three most-recent Five-Year Plan (FYP) periods (2001–2015). A new decomposition method was then used to assess the impact of PM2.5 variations and demographic changes on the exposure variation. Within the decomposition framework, an index of pollution-population-coincidence–induced PM2.5 exposure (PPCE) was introduced to characterize the interaction of PM2.5 and the population distribution. The results showed that the 15-year average PPCE levels in all cities were positive (e.g., 6 µg/m3 in Guangzhou), suggesting that unfavorable city planning had led to people dwelling in polluted areas. An analyses of the spatial differences in PM2.5 changes showed that urban areas experienced a greater decrease in PM2.5 concentration than did rural areas in most cities during the 11th (2006–2010) and 12th (2011–2015) FYP periods. These spatial differences in PM2.5 changes reduced the PPCE levels of these cities and thus reduced the exposure levels (by as much as -0.58 µg/m3/year). The population migration resulting from rapid urbanization, however, increased the PPCE and exposure levels (by as much as 0.18 µg/m3/year) in most cities during the three FYP periods considered. Dongguan was a special case in that the demographic change reduced the exposure level because of its rapid development of residential areas in cleaner regions adjacent to Shenzhen. The exposure levels in all cities remained high because of the high mean PM2.5 concentrations and their positive PPCE. To better protect public health, control efforts should target densely populated areas and city planning should locate more people in cleaner areas.

scholarly journals The rationality of PM2.5 monitoring sites’ locations based on exposure level across eastern China

2021 ◽  
Author(s):  
Chang Yan ◽  
Guangming Shi ◽  
Fumo Yang
Keyword(s):  
Urban Areas ◽  
Population Distribution ◽  
Eastern China ◽  
Population Exposure ◽  
Exposure Level ◽  
Site Location ◽  
Spatial Coverage ◽  
Exposure Levels ◽  
Pm2.5 Concentration ◽  
Monitoring Stations

Abstract Due to the heterogeneity of PM2.5 and population distribution, the representativeness of existing monitoring sites is questionable when the monitored data were used to assess the population exposure. By comparing the PM2.5 concentration from a satellite-based dataset named the China High Air Pollutants (CHAP), population and exposure level in urban areas with monitoring stations (UWS) and without monitoring stations (UNS), we discussed the rationality of the current spatial coverage of monitoring stations in eastern China. Through an analysis of air pollution in all urban areas of 256 prefectural-level municipalities in eastern China, we found that the average PM2.5 concentration in UNS in 2015 and 2018 were 52.26 μg/m3 and 41.32 μg/m3, respectively, which were slightly lower than that in UWS (52.98 μg/m3 and 41.48 μg/m3). About 12.1% of the prefectural-level municipalities had higher exposure levels in certain UNS than those in UWS. With the faster growth of UNS population, the gap between exposure levels of UNS and UWS were narrowing. Hence, currently prevalent administration-based principle of site location selection might have higher risk of missing the non-capital urban areas with relatively higher PM2.5 exposure level in the future.

scholarly journals Impacts of Emission Reduction Technological Changes on China’s City-Level PM2.5 Concentration Based on Sustainable Development

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Jiandong Chen ◽  
Yu Wei ◽  
Ming Gao ◽  
Shuo Huang
Keyword(s):  
Emission Reduction ◽  
Critical Role ◽  
Technological Changes ◽  
Index Method ◽  
Econometric Methods ◽  
Energy Technologies ◽  
Spatial Differences ◽  
Level Scale ◽  
The Impact ◽  
Pm2.5 Concentration

As an important field for human activities, cities play a critical role in PM2.5 reductions. Among the determinants for PM2.5 concentration, technological progress is considered to exhibit significant inhibitory effects. Although most extant research has focused on energy technologies or total factor productivity, due to limitations in data and methods, few scholars have focused on emission reduction technological changes at a city-level scale. Therefore, based on the combination of k-means clustering and the log-mean Divisia index method, this study estimates and explores the impact of PM2.5 emission reduction technology (PME) on the temporal changes and spatial differences of 262 Chinese cities’ PM2.5 concentration during 2003–2017. The findings show the following: (1) although the results based on econometric methods indicate that emission reduction technological changes decreased China’s city-level PM2.5 concentration, there were turning points in the yearly impacts, indicating that the improvements to emission reduction efficiency were not stable; (2) compared with PME, energy intensity played a more stable role in PM2.5 emissions reductions, implying that the improvement of energy efficiency was still very important in controlling PM2.5 concentrations; (3) based on the classified groups after clustering, most cities’ PME contributed to negative differences, but the PME of a small number of cities was very weak to largely lower the average level of their group; and (4) distributions of the spatial decomposition of the three classified groups were stable in the period of 2003–2017, implying that the catch-up and transcendence effects of PME within the group were limited. Thus, policymakers should focus on the impact of different policies on PME differences between cities.

scholarly journals Assessing Effect of Targeting Reduction of PM2.5 Concentration on Human Exposure and Health Burden in Hong Kong Using Satellite Observation

2018 ◽  
Vol 10 (12) ◽  
pp. 2064 ◽  
Author(s):  
Changqing Lin ◽  
Alexis Lau ◽  
Xingcheng Lu ◽  
Jimmy Fung ◽  
Zhiyuan Li ◽  
...  
Keyword(s):  
Hong Kong ◽  
Diagnostic Tests ◽  
Human Exposure ◽  
Health Benefits ◽  
Premature Mortality ◽  
Population Exposure ◽  
Exposure Level ◽  
Study Region ◽  
Health Burden ◽  
Pm2.5 Concentration

Targeting reduction of PM2.5 concentration lessens population exposure level and health burden more effectively than uniform reduction does. Quantitative assessment of effect of the targeting reduction is limited because of the lack of spatially explicit PM2.5 data. This study aimed to investigate extent of exposure and health benefits resulting from the targeting reduction of PM2.5 concentration. We took advantage of satellite observations to characterize spatial distribution of PM2.5 concentration at a resolution of 1 km. Using Hong Kong of China as the study region (804 satellite’s pixels covering its residential areas), human exposure level (cρ) and premature mortality attributable to PM2.5 (Mort) for 2015 were estimated to be 25.9 μg/m3 and 4112 people per year, respectively. We then performed 804 diagnostic tests that reduced PM2.5 concentrations by −1 μg/m3 in different areas and a reference test that uniformly spread the −1 μg/m3. We used a benefit rate from targeting reduction (BRT), which represented a ratio of declines in cρ (or Mort) with and without the targeting reduction, to quantify the extent of benefits. The diagnostic tests estimated the BRT levels for both human exposure and premature mortality to be 4.3 over Hong Kong. It indicates that the declines in human exposure and premature mortality quadrupled with a targeting reduction of PM2.5 concentration over Hong Kong. The BRT values for districts of Hong Kong could be as high as 5.6 and they were positively correlated to their spatial variabilities in population density. Our results underscore the substantial exposure and health benefits from the targeting reduction of PM2.5 concentration. To better protect public health in Hong Kong, super-regional and regional cooperation are essential. Meanwhile, local environmental policy is suggested to aim at reducing anthropogenic emissions from mobile and area (e.g., residential) sources in central and northwestern areas.

scholarly journals Assessment of exposure determinants and exposure levels by using stationary concentration measurements and a probabilistic near-field/far-field exposure model

2021 ◽  
Vol 1 ◽  
pp. 72
Author(s):  
Antti Joonas Koivisto ◽  
Andrea Spinazzè ◽  
Frederik Verdonck ◽  
Francesca Borghi ◽  
Jakob Löndahl ◽  
...  
Keyword(s):  
Near Field ◽  
Exposure Model ◽  
Exposure Level ◽  
Far Field ◽  
Worst Case ◽  
Stationary Concentration ◽  
Exposure Determinants ◽  
Local Ventilation ◽  
Exposure Levels ◽  
The Impact

Background: The Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) regulation requires the establishment of Conditions of Use (CoU) for all exposure scenarios to ensure good communication of safe working practices. Setting CoU requires the risk assessment of all relevant Contributing Scenarios (CSs) in the exposure scenario. A new CS has to be created whenever an Operational Condition (OC) is changed, resulting in an excessive number of exposure assessments. An efficient solution is to quantify OC concentrations and to identify reasonable worst-case scenarios with probabilistic exposure modeling. Methods: Here, we appoint CoU for powder pouring during the industrial manufacturing of a paint batch by quantifying OC exposure levels and exposure determinants. The quantification was performed by using stationary measurements and a probabilistic Near-Field/Far-Field (NF/FF) exposure model. Work shift and OC concentration levels were quantified for pouring TiO2 from big bags and small bags, pouring Micro Mica from small bags, and cleaning. The impact of exposure determinants on NF concentration level was quantified by (1) assessing exposure determinants correlation with the NF exposure level and (2) by performing simulations with different OCs. Results: Emission rate, air mixing between NF and FF and local ventilation were the most relevant exposure determinants affecting NF concentrations. Potentially risky OCs were identified by performing Reasonable Worst Case (RWC) simulations and by comparing the exposure 95th percentile distribution with 10% of the occupational exposure limit value (OELV). The CS was shown safe except in RWC scenario (ventilation rate from 0.4 to 1.6 1/h, 100 m3 room, no local ventilation, and NF ventilation of 1.6 m3/min). Conclusions: The CoU assessment was considered to comply with European Chemicals Agency (ECHA) legislation and EN 689 exposure assessment strategy for testing compliance with OEL values. One RWC scenario would require measurements since the exposure level was 12.5% of the OELV.

RF-EMF EXPOSURE LEVELS IN SENSITIVE LAND USE IN GREECE: EDUCATIONAL UNITS CENSUS IN THE MUNICIPALITY OF KORYDALLOS

2020 ◽  
Vol 190 (2) ◽  
pp. 193-199
Author(s):  
Aris Alexias ◽  
Yiannis Kiouvrekis ◽  
Vasiliki Softa ◽  
Constantin Kappas ◽  
Charilaos Tyrakis ◽  
...  
Keyword(s):  
Land Use ◽  
Mobile Phones ◽  
Mean Value ◽  
Exposure Level ◽  
Limit Set ◽  
Exposure Limits ◽  
Primary And Secondary Education ◽  
Exposure Levels ◽  
The Mean

Abstract Background The growing popularity of mobile phones and the expansion of network infrastructure in Greece have raised concerns about the possible negative health effects on sensitive groups, such as children, from exposure to long-term radiofrequency electromagnetic fields (RF-EMFs). Aims The objective of this study is to estimate mean RF-EMF exposure levels of primary and secondary education schools located in the municipality of Korydallos, Athens, Greece. Methods We performed measurements to all the schools units ($n=62$) in the region in order to calculate the mean value for RF-EMF exposure in the range of 27 MHz–3 GHz, which covers the whole spectrum of RF-EMF sources. Results At the $97.5\%$ of schools found in Korydallos region, the exposure level is at least 2200 times below the Greek exposure limits. Conclusion The exposure levels in the locations tested are both below $60\%$ of the highest limit set by the International Commission on Non-Ionizing Radiation Protection regarding school exposures.

scholarly journals The Impact of Targeted Trap–Neuter–Return Efforts in the San Francisco Bay Area

Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2089
Author(s):  
Daniel D. Spehar ◽  
Peter J. Wolf
Keyword(s):  
San Francisco ◽  
San Francisco Bay ◽  
San Francisco Bay Area ◽  
Southeastern United States ◽  
The West ◽  
Bay Area ◽  
Feeding Regimen ◽  
The Impact ◽  
The U.S

Recently, a growing collection of evidence that associates trap–neuter–return (TNR) programs with substantial and sustained reductions in community cat populations across a variety of environments has emerged. Peer-reviewed studies emanating from the northeastern, midwestern, and southeastern United States, as well as Australia, document such reductions. The present study expands upon this body of evidence by examining the impact of a long-term TNR program on a population of community cats residing on a pedestrian trail adjacent to an oceanic bay located on the West Coast of the U.S. A population of 175 community cats, as determined by an initial census, living on a 2-mile section of the San Francisco Bay Trail declined by 99.4% over a 16-year period. After the conclusion of the initial count, the presence of cats was monitored as part of the TNR program’s daily feeding regimen. Of the 258 total cats enrolled in the program between 2004 and 2020, only one remained at the end of the program period. These results are consistent with those documented at the various sites of other long-term TNR programs.

Sensitivity of carbon fluxes to flash drought based on long-term FLUXNET and satellite observations

2020 ◽  
Author(s):  
Miao Zhang ◽  
Xing Yuan
Keyword(s):  
Extreme Case ◽  
High Sensitivity ◽  
Carbon Fluxes ◽  
Rapid Onset ◽  
Satellite Observations ◽  
Use Efficiency ◽  
The Impact ◽  
Specific Definition

<p>Flash drought is characterized by a rapid onset at subseasonal time scale and enormous impact on society and economics. However, only few extreme case studies assessed the impact of flash drought on vegetation, without specific definition to identify the rapidly intensification stage of flash drought. Here, we use soil moisture to identity flash drought events at in-situ and regional scales, and detect the response of vegetation photosynthetic function using eddy covariance and satellite observations of carbon fluxes and sun-induced chlorophyll fluorescence (SIF). Different vegetation types show high sensitivity to flash drought especially for savanna and grassland, and the lag time between flash drought and ecological response is usually 8-16 days. The resistance of woody plants can be attributed to the positive anomalies of inherent water use efficiency during flash drought. Vegetation over semi-arid and semi-humid is also vulnerable to flash drought. The quick response of vegetation to flash drought is a new challenge for drought monitoring.</p>

Emerging issues of HT-2 and T-2 toxins in European cereal production

2009 ◽  
Vol 2 (2) ◽  
pp. 173-179 ◽  
Author(s):  
S. Edwards ◽  
B. Barrier-Guillot ◽  
P-E. Clasen ◽  
V. Hietaniemi ◽  
H. Pettersson
Keyword(s):  
Daily Intake ◽  
Human Consumption ◽  
Cereal Species ◽  
Highly Sensitive ◽  
Emerging Issues ◽  
Exposure Levels ◽  
The Individual ◽  
The Impact ◽  
Retail Products

HT-2 and T-2 toxins are two of the most potent trichothecenes; they have a combined (HT-2+T-2) temporary Tolerable Daily Intake (TDI) of 0.06 µg/kg body weight/day. The distribution of HT-2 and T-2 appears to be largely restricted to Europe. Of the cereal species, HT-2 and T-2 usually have higher incidences and concentrations on oats followed by barley and then wheat, however, this can vary between countries. Survey data from Nordic countries have indicated that these mycotoxins have increased in recent years, reaching concentrations of >1000 µg/kg HT-2+T-2 in some samples. HT-2 and T-2 have also been detected in malting barley in France, and in particular in spring sown varieties. A newly identified species, Fusarium langsethiae, has been implicated as a producer of HT-2 and T-2 in European cereals. There is limited data available regarding this species' pathogenicity and mycotoxin production. The impact of agronomy on the concentration of HT-2 and T-2 in cereals has not been clearly identified, but it is evident that it is different to the impact of agronomy on deoxynivalenol. Processing of cereals can have a major impact on the HT-2 and T-2 content of cereals. Oats are de-hulled during processing for human consumption; de-hulling reduces the mycotoxin content of oats by more than 90%. During the malting and brewing of barley the concentration of HT-2 and T-2 increases and decreases within various stages of the processes and the final mycotoxin load of beers will depend on the individual processes used by each maltster and brewer. Whether these mycotoxins are an issue for human health cannot be determined until a full TDI is calculated based on more long-term exposure studies, and human exposure levels are calculated from surveys of retail products using new, highly sensitive assays.

scholarly journals Intake and Uptake of Chemicals Upon Use of Various Tobacco/Nicotine Products: Can Users be Differentiated by Single or Combinations of Biomarkers?

2021 ◽  
Vol 30 (4) ◽  
pp. 167-198
Author(s):  
Gerhard Scherer ◽  
Nikola Pluym ◽  
Max Scherer
Keyword(s):  
Electronic Cigarettes ◽  
The Other ◽  
Published Data ◽  
Exposure Level ◽  
Nicotine Gum ◽  
Tobacco Products ◽  
Exposure Levels ◽  
New Generation ◽  
The Impact ◽  
Relative Exposure

Summary With increasing use of new generation tobacco/nicotine products (TNPs) instead or in addition to conventional cigarettes (CCs), the question arises, whether the user of these new TNPs and CCs can be distinguished on the basis of their exposure in terms of intake and uptake of specific chemicals. For this purpose, the exposure to chemicals for users of 5 product types including CCs, HNB (heat-not-burn products), electronic cigarettes (ECs), oral tobacco products (OT, with the focus on snus), nicotine replacement therapy (NRT) products (only nicotine gum (NG) was considered in this study) was evaluated on the basis of published data. For both intake and biomarker-based uptake, 4 relative exposure levels with the assigned values from 1 (lowest exposure) to 4 (highest exposure) were defined resulting in exposure level patterns. Unique single-biomarker-based exposure levels were found for smokers (11 chemicals), vapers (1 chemical) and non-users (NU, 1 chemical). A few selected biomarkers (usually with relative levels of 3–4) were found to be sufficient for unequivocal differentiation of one user/NU group from the other 5 groups. The impact of dual-product use is also briefly discussed. [Contrib. Tob. Nicotine Res. 30 (2021) 167–198]

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