scholarly journals Spatiotemporal Ozone Level Variation in Urban Forests in Shenzhen, China

Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 247 ◽  
Author(s):  
Wenjun Duan ◽  
Cheng Wang ◽  
Nancai Pei ◽  
Chang Zhang ◽  
Lin Gu ◽  
...  
Keyword(s):  
Air Quality ◽  
Urban Forest ◽  
Surface Ozone ◽  
Urban Forests ◽  
Ambient Air ◽  
Daily Maximum ◽  
Ozone Level ◽  
Night Time ◽  
Recreational Activities ◽  
Forest Park

This study is among the first to investigate ozone levels in urban forests in China. It establishes that urban forest air quality in Yuanshan Forest Park (Shenzhen) is suitable for recreational activities and identifies spatial, seasonal, and diurnal O3 patterns and relationships with micrometeorological parameters, suggesting the possibility of manipulating relevant forest characteristics to reduce Surface ozone (O3) levels. An understanding of O3 levels of urban forest environments is needed to assess potential effects on human health and recreational activities. Such studies in China are scarce. This study investigated urban forest O3 levels to improve understanding and support residents engaging in forest recreational activities. We monitored O3 levels in 2015–2016 for three urban forests representing common habitats (foothill, valley, and ridge) in Yuanshan Forest Park and for an adjacent square. The overall mean daily and daily maximum 8 h mean (MDA8) O3 concentrations were highest for the ridge forest and lowest for the valley forest. Each forest’s O3 concentrations were highest in summer. Diurnally, forest O3 concentrations peaked between 13:00 and 17:00 and reached a minimum between 03:00 and 09:00. The correlation between forest O3 concentrations and air temperature (AT) was strongly positive in summer and autumn but negative in spring. In each season, O3 concentration was negatively correlated with relative humidity (RH). No MDA8 or hourly O3 concentrations in the forests exceeded National Ambient Air Quality Standard Grade I thresholds (100 and 160 μg m−3, respectively). O3 accumulation is present in ridge urban forest in all seasons. Foothill and valley urban forests have better air quality than ridge forestation. Urban forest air quality is better in spring and autumn than in summer and is better from night-time to early morning than from noon to afternoon.

scholarly journals Spatiotemporal Ozone Level Variation in Urban Forests in Shenzhen, China

2019 ◽  
Author(s):  
Wenjun Duan ◽  
Cheng Wang ◽  
Nancai Pei ◽  
Chang Zhang ◽  
Lin Gu ◽  
...  
Keyword(s):  
Air Quality ◽  
Urban Forest ◽  
Urban Forests ◽  
Ambient Air ◽  
Quality Standard ◽  
Daily Maximum ◽  
Ozone Level ◽  
Night Time ◽  
Recreational Activities ◽  
Forest Park

Abstract: Research Highlights: This study is among the first to investigate ozone levels in urban forests in China. It establishes that urban forest air quality in Yuanshan Forest Park, Shenzhen, is suitable for recreational activities and identifies spatial, seasonal, and diurnal O3 patterns and relationships with micrometeorological parameters, suggesting the possibility of manipulating relevant forest characteristics to reduce O3 levels. Background and Objectives: An understanding of O3 levels of urban forest environments is needed to assess potential effects on human health and recreational activities. Such studies in China are scarce. This study investigated urban forest O3 levels to improve understanding and support residents engaging in forest recreational activities. Materials and Methods: We monitored O3 levels in 2015–2016 for three urban forests representing common habitats (foothill, valley, and ridge) in Yuanshan Forest Park, Shenzhen, and for an adjacent square. Results: The overall mean daily and daily maximum 8-h mean (MDA8) O3 concentrations were highest for the ridge forest and lowest for the valley forest. Each forest’s O3 concentrations were highest in summer. Diurnally, forest O3 concentrations peaked between 13:00 and 17:00 and reached a minimum between 03:00 and 09:00. The correlation between forest O3 concentrations and air temperature (AT) was strongly positive in summer and autumn but negative in spring. In each season, O3 concentration was negatively correlated with relative humidity (RH). No MDA8 or hourly O3 concentrations in the forests exceeded National Ambient Air Quality Standard Grade I thresholds (100 and 160 μg m−3, respectively). Conclusions: O3 accumulation is present in ridge urban forest in all seasons. Foothill and valley urban forests have better air quality than ridge forestation. Urban forest air quality is better in spring and autumn than in summer and is better from night-time to early morning than from noon to afternoon.

scholarly journals Ozone and NO<sub>x</sub> chemistry in the eastern US: evaluation of CMAQ/CB05 with satellite (OMI) data

2015 ◽  
Vol 15 (4) ◽  
pp. 4427-4461 ◽  
Author(s):  
T. P. Canty ◽  
L. Hembeck ◽  
T. P. Vinciguerra ◽  
D. C. Anderson ◽  
D. L. Goldberg ◽  
...  
Keyword(s):  
Air Quality ◽  
Surface Ozone ◽  
Quality Standards ◽  
Ambient Air ◽  
Daily Maximum ◽  
Air Quality Model ◽  
Ozone Monitoring Instrument ◽  
Air Quality Standards ◽  
The Us ◽  
Us Northeast

Abstract. 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 precursors within CMAQ. Observations of tropospheric column NO2 from the Ozone Monitoring Instrument (OMI), retrieved by two independent groups, show that the model overestimates urban NO2 and underestimates rural NO2 under all conditions examined for July and August 2011 in the US Northeast. The overestimate of the urban to rural ratio of tropospheric column NO2 for this baseline run of CMAQ (CB05 mechanism, mobile NOx emissions from the National Emissions Inventory; isoprene emissions from MEGAN v2.04) suggests this model may under estimate the importance of interstate transport of NOx. This CMAQ simulation leads to a considerable overestimate of the 2 month average of 8 h daily maximum surface ozone in the US Northeast, as well as an overestimate of 8 h ozone at AQS sites during days when the state of Maryland experienced NAAQS exceedances. We have implemented three changes within CMAQ motivated by OMI NO2 as well as aircraft observations obtained in July 2011 during the NASA DISCOVER-AQ campaign: (a) the modeled lifetime of organic nitrates within CB05 has been reduced by a factor of 10, (b) emissions of NOx from mobile sources has been reduced by a factor of 2, and (c) isoprene emissions have been reduced by using MEGAN v2.10 rather than v2.04. Compared to the baseline simulation, the CMAQ run using all three of these changes leads to a considerably better simulation of the ratio of urban to rural column NO2, better agreement with the 2 month average of daily 8 h maximum ozone in the US Northeast, fewer number of false positives of an ozone exceedance throughout the domain, as well as an unbiased simulation of surface ozone at ground based AQS sites in Maryland that experienced an ozone exceedance during July and August 2007. These modifications to CMAQ may provide a framework for use in studies focused on achieving future adherence to specific air quality standards for surface ozone by reducing emission of NOx from various anthropogenic sectors.

scholarly journals Spatio-temporal of surface ozone (O3) variations at urban and suburban sites in Sarawak region of Malaysia

2021 ◽  
Vol 880 (1) ◽  
pp. 012004
Author(s):  
H Mahidin ◽  
M T Latif ◽  
A Hamdan ◽  
J Salleh ◽  
D Dominick ◽  
...  
Keyword(s):  
Air Quality ◽  
Surface Ozone ◽  
Ambient Air ◽  
Quality Standard ◽  
Transportation Systems ◽  
Pollutant Emissions ◽  
Daily Maximum ◽  
Spatio Temporal ◽  
Ambient Air Quality Standard ◽  
The Relationship

Abstract Sarawak Region of Malaysia is currently experiencing a high demand for capital needs such as transformation forest to plantations, economic development, and improving transportation systems. Those land cover changes will increase primary pollutant emissions and trigger surface O3 formation. Surface O3 is a secondary pollutant and a significant greenhouse gas contributing to climate change and declining air quality. In this study, variations in surface O3 concentrations at urban and suburban sites in Sarawak were explored using the Malaysian Department of Environment data spanning a two-year cycle (2018-2019). The primary aim of this study is to ascertain the variation of surface O3 concentrations reported at four monitoring stations in Sarawak, namely Kuching (SQ1) (Urban), Sibu (SQ2) (Suburban), Bintulu (SQ3) (Suburban), and Miri (SQ4) (Suburban). The study also analysed the relationship between O3 distribution and nitrogen oxides (NO and NO2). The findings showed that O3 concentrations observed in the region during the study period were lower than the maximum permissible value of 100 ppbv suggested by the Malaysian Ambient Air Quality Standard (2020). SQ4 (Miri) at suburban sites recorded the highest average surface O3 concentrations with an hourly average and daily maximum O3 concentration of 15.7 and 89.5 ppbv, respectively. Temperatures, UV exposure, and wind speed all impact the concentration of surface O3 in Sarawak. In all stations, concentrations of O3 were inversely linked with NO, NO2, and relative humidity (RH). This research will assist the relevant agency in forecast, monitor, and mitigate the level of O3 in the ambient environment, especially in the Sarawak Region.

scholarly journals Evaluation of modeled surface ozone biases as a function of cloud cover fraction

2015 ◽  
Vol 8 (4) ◽  
pp. 3219-3233 ◽  
Author(s):  
H. C. Kim ◽  
P. Lee ◽  
F. Ngan ◽  
Y. Tang ◽  
H. L. Yoo ◽  
...  
Keyword(s):  
Air Quality ◽  
Surface Ozone ◽  
Daily Maximum ◽  
Ozone Level ◽  
Air Quality Forecast ◽  
Moderate Resolution ◽  
Regional Air Quality ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Quality Forecast

Abstract. A regional air-quality forecast system's model of surface ozone variability based on cloud coverage is evaluated using satellite-observed cloud fraction (CF) information and a surface air-quality monitoring system. We compared CF and daily maximum ozone from the National Oceanic and Atmospheric Administration's National Air Quality Forecast Capability (NOAA NAQFC) with CFs from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the U.S. Environmental Protection Agency's AirNow surface ozone measurements during May to October 2014. We found that observed surface ozone shows a clear (negative) correlation with the MODIS CFs, showing around 1 ppb decrease for 10% MODIS CF change over the Contiguous United States, while the correlation of modeled surface ozone with the model CFs is much weaker, showing only −0.5 ppb per 10% NAQFC CF change. Further, daytime CF differences between MODIS and NAQFC are correlated with modeled surface-ozone biases between AirNow and NAQFC, showing −1.05 ppb per 10% CF change, implying that spatial- and temporal-misplacement of the modeled cloud field might have biased modeled surface ozone-level. Current NAQFC cloud fields seem to be too bright compared to MODIS cloud fields (mean NAQFC CF = 0.38 and mean MODIS CF = 0.55), contributing up to 35% of surface-ozone bias in the current NAQFC system.

scholarly journals Ozone and NO<sub><i>x</i></sub> chemistry in the eastern US: evaluation of CMAQ/CB05 with satellite (OMI) data

2015 ◽  
Vol 15 (19) ◽  
pp. 10965-10982 ◽  
Author(s):  
T. P. Canty ◽  
L. Hembeck ◽  
T. P. Vinciguerra ◽  
D. C. Anderson ◽  
D. L. Goldberg ◽  
...  
Keyword(s):  
Air Quality ◽  
Rural Areas ◽  
Surface Ozone ◽  
Quality Standards ◽  
Ambient Air ◽  
Daily Maximum ◽  
Air Quality Model ◽  
Air Quality Standards ◽  
The Us ◽  
Us Northeast

Abstract. 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 precursors within CMAQ. Observations of tropospheric column NO2 from the Ozone Monitoring Instrument (OMI), retrieved by two independent groups, show that the model overestimates urban NO2 and underestimates rural NO2 under all conditions examined for July and August 2011 in the US Northeast. The overestimate of the urban to rural ratio of tropospheric column NO2 for this baseline run of CMAQ (CB05 mechanism, mobile NOx emissions from the National Emissions Inventory; isoprene emissions from MEGAN v2.04) suggests this model may underestimate the importance of interstate transport of NOx. This CMAQ simulation leads to a considerable overestimate of the 2-month average of 8 h daily maximum surface ozone in the US Northeast, as well as an overestimate of 8 h ozone at AQS sites during days when the state of Maryland experienced NAAQS exceedances. We have implemented three changes within CMAQ motivated by OMI NO2 as well as aircraft observations obtained in July 2011 during the NASA DISCOVER-AQ campaign: (a) the modeled lifetime of organic nitrates within CB05 has been reduced by a factor of 10, (b) emissions of NOx from mobile sources has been reduced by a factor of 2, and (c) isoprene emissions have been reduced by using MEGAN v2.10 rather than v2.04. Compared to the baseline simulation, the CMAQ run using all three of these changes leads to considerably better simulation of column NO2 in both urban and rural areas, better agreement with the 2-month average of daily 8 h maximum ozone in the US Northeast, fewer number of false positives of an ozone exceedance throughout the domain, as well as an unbiased simulation of surface ozone at ground-based AQS sites in Maryland that experienced an ozone exceedance during July and August 2007. These modifications to CMAQ may provide a framework for use in studies focused on achieving future adherence to specific air quality standards for surface ozone by reducing emission of NOx from various anthropogenic sectors.

scholarly journals Evaluation of modeled surface ozone biases as a function of cloud cover fraction

2015 ◽  
Vol 8 (9) ◽  
pp. 2959-2965 ◽  
Author(s):  
H. C. Kim ◽  
P. Lee ◽  
F. Ngan ◽  
Y. Tang ◽  
H. L. Yoo ◽  
...  
Keyword(s):  
Air Quality ◽  
Surface Ozone ◽  
Daily Maximum ◽  
Ozone Level ◽  
Air Quality Forecast ◽  
The Us ◽  
Moderate Resolution ◽  
Regional Air Quality ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Quality Forecast

Abstract. A regional air-quality forecast system's model of surface ozone variability based on cloud coverage is evaluated using satellite-observed cloud fraction (CF) information and a surface air-quality monitoring system. We compared CF and daily maximum ozone from the National Oceanic and Atmospheric Administration's National Air Quality Forecast Capability (NOAA NAQFC) with CFs from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the US Environmental Protection Agency's AirNow surface ozone measurements during May to October 2014. We found that observed surface ozone shows a negative correlation with the MODIS CFs, showing around 1 ppb decrease for 10 % MODIS CF change over the contiguous United States, while the correlation of modeled surface ozone with the model CFs is much weaker, showing only −0.5 ppb per 10 % NAQFC CF change. Further, daytime CF differences between MODIS and NAQFC are correlated with modeled surface-ozone biases between AirNow and NAQFC, showing −1.05 ppb per 10 % CF change, implying that spatial and temporal misplacement of the modeled cloud field might have biased modeled surface ozone level. Current NAQFC cloud fields seem to have fewer CFs compared to MODIS cloud fields (mean NAQFC CF = 0.38 and mean MODIS CF = 0.55), contributing up to 35 % of surface-ozone bias in the current NAQFC system.

scholarly journals Assessing the Ecological Value of an Urban Forest Park: A Case Study of Sinhua Forest Park in Taiwan

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 806
Author(s):  
Wan-Yu Liu ◽  
Yo-Zheng Lin ◽  
Chi-Ming Hsieh
Keyword(s):  
Urban Forest ◽  
Contingent Valuation Method ◽  
Urban Forests ◽  
Green Spaces ◽  
Socioeconomic Background ◽  
Tobit Regression ◽  
Ecological Value ◽  
Forest Park ◽  
Study Results ◽  
Ecological Conservation

Urban forests offer multiple functions: they can balance negative effects from the environment and provide the public with a place for leisure and recreation. Hence, urban forests are crucial to urban ecology and have been widely studied. In addition, relevant study results were applied for policymaking in urban development and forest park management. This study evaluated the ecological value of the Sinhua Forest Park and examined whether the socioeconomic background of participants influences their willingness to pay (WTP) for ecological conservation. Questionnaires were distributed to visitors in the Sinhua Forest Park in Tainan, Taiwan, and the payment card format of the contingent valuation method was employed to evaluate the ecological value. The results showed that the visitors had an annual WTP of $22.01 per person. However, when samples with protest responses were excluded, the WTP rose to $24.58. By considering the total number of visitors of a year, the total ecological value was $1,426,964.14/year and reached $1,593,257.31/year after excluding the protest samples. This study also analyzed participants’ within-variable socioeconomic background (e.g., gender and education) and discovered that male participants who are aged 60 years or older, with an education level of senior/vocational high school, and those who visited green spaces two to three times per week presented a high WTP score on average. A Tobit regression model was employed for examination, and the results indicated that participants’ education and frequency of visiting green spaces significantly influenced their WTP for the ecological conservation of the Sinhua Forest Park.

scholarly journals Beijing Resident’s Preferences of Ecosystem Services of Urban Forests

Forests ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 14
Author(s):  
Han Zhi-Ying ◽  
Youn Yeo-Chang
Keyword(s):  
Ecosystem Services ◽  
Air Quality ◽  
Fresh Water ◽  
Urban Forest ◽  
Urban Forestry ◽  
Urban Forests ◽  
Wildlife Habitat ◽  
Quality Regulation ◽  
Water Provision ◽  
Air Quality Regulation

This paper aims to investigate the Beijing resident’s preferences over various options of urban forest management strategies. The literature investigation and expert Delphi method were conducted to classify the ecosystem services of urban forests into six categories: (1) fresh water provision, (2) noise reduction, (3) moderation of extreme events, (4) air quality regulation, (5) species diversity and wildlife habitat, and (6) recreation and spiritual experience. To elicit the relative preferences to ecosystem service (hereafter referred to as ES) of Beijing residents, we employed the choice experiment method. The data were collected by interviews with questionnaires conducted in October 2017, and a total of 483 valid questionnaires were analyzed. The subjects of this experiment were residents older than 19 years old who have lived in Beijing for more than 1 year and have visited any one of the urban forests located in Beijing more than once during 2016. The results were as follows: Firstly, the air quality regulation ES was considered as the most important service for Beijing residents in terms of their choices of urban forest. In addition, Beijing residents regarded the fresh water provision ES as the second most important ES. Beijing residents were willing to pay up to 1.84% of the average monthly income of Chinese households annually to expand urban forest ecosystems in order to improve air quality. Secondly, apartment owners were willing to pay more municipality tax for forest ESs than residents who did not own an apartment. Thirdly, residents were more willing to pay for urban forest ESs as their income increases. The results indicated that Beijing residents were willing to pay more tax in support of urban forestry for air quality improvement. This research suggests that urban environmental policy makers in Beijing should pay more attention to the regulation function of forests (especially improving air quality) when designing and managing urban forests.

scholarly journals Visitors’ emotional expression in urban forest parks: What can we know about on-line facial images from the Social Networking Services?

2017 ◽  
Author(s):  
Haoming Guan ◽  
Honxu Wei ◽  
Xingyuan He ◽  
Zhibin Ren ◽  
Xin Chen ◽  
...  
Keyword(s):  
Social Networking ◽  
Facial Expressions ◽  
Urban Forest ◽  
Urban Forests ◽  
Well Being ◽  
Social Networking Services ◽  
Forest Park ◽  
The Social ◽  
Forest Parks ◽  
Facial Images

Urban forests can attract visitors by the function of well-being improvement, which can be evaluated by analyzing the big-data from the social networking services (SNS). In this study, 935 facial images of visitors to nine urban forest parks were screened and downloaded from check-in records in the SNS platform of Sina Micro-Blog at cities of Changchun, Harbin, and Shenyang in Northeast China. Images were recognized for facial expressions by FaceReaderTM to read out eight emotional expressions: neutral, happy, sad, angry, surprised, scared, disgusted, and contempt. The number of images by women was larger than that by men. Compared to images from Changchun, those from Shenyang harbored higher neutral degree, which showed a positive relationship with the distance of forest park from downtown. In Changchun, the angry, surprised, and disgusted degrees decreased with the increase of distance of forest park from downtown, while the happy and disgusted degrees showed the same trend in Shenyang. In forest parks at city center and remote-rural areas, the neutral degree was positively correlated with the angry, surprised and contempt degrees but negatively correlated with the happy and disgusted degrees. In the sub-urban area the correlation of neutral with both surprised and disgusted degrees disappeared. Our study can be referred to by urban planning to evaluate the perceived well-being in urban forests through analyzing facial expressions of images from SNS.

scholarly journals Characterizing sources of high surface ozone events in the southwestern U.S. with intensive field measurements and two global models

2019 ◽  
Author(s):  
Li Zhang ◽  
Meiyun Lin ◽  
Andrew O. Langford ◽  
Larry W. Horowitz ◽  
Christoph J. Senff ◽  
...  
Keyword(s):  
Large Scale ◽  
Las Vegas ◽  
Surface Ozone ◽  
Field Measurements ◽  
Ambient Air ◽  
Daily Maximum ◽  
Global Models ◽  
High Background ◽  
Stratospheric Intrusions ◽  
Surface O3

Abstract. The detection and attribution of high background ozone (O3) events in the southwestern U.S. is challenging but relevant to the effective implementation of the lowered National Ambient Air Quality Standard (NAAQS; 70 ppbv). Here we leverage intensive field measurements from the Fires, Asian, and Stratospheric TransportLas Vegas Ozone Study (FAST-LVOS) in MayJune 2017, alongside high-resolution simulations with two global models (GFDL-AM4 and GEOS-Chem), to pinpoint the sources of O3 during high-O3 events. We show stratospheric influence on four out of the ten events with daily maximum 8-hour average (MDA8) surface O3 above 65 ppbv in the greater Las Vegas region. While O3 produced from regional anthropogenic emissions dominates pollution in the Las Vegas Valley, stratospheric intrusions can mix with regional pollution to push surface O3 above 70 ppbv. GFDL-AM4 captures the key characteristics of deep stratospheric intrusions consistent with ozonesondes, lidar profiles, and co-located measurements of O3, CO, and water vapor at Angel Peak, whereas GEOS-Chem has difficulty simulating the observed features and underestimates observed O3 by ~ 20 ppbv at the surface. The two models also differ substantially during a wildfire event, with GEOS-Chem estimating ~ 15 ppbv greater O3, in better agreement with lidar observations. At the surface, the two models bracket the observed MDA8 O3 values during the wildfire event. Both models capture the large-scale transport of Asian pollution, but neither resolves some fine-scale pollution plumes, as evidenced from aerosol backscatter, aircraft, and satellite measurements. U.S. background O3 estimates from the two models differ by 5 ppbv on average and up to 15 ppbv episodically. Our multi-model approach tied closely to observational analysis yields process insights, suggesting that elevated background O3 may pose challenges to achieving a potentially lower NAAQS level (e.g., 65 ppbv) in the southwestern U.S.

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