Observed slump of sea land breeze in Brisbane under the effect of aerosols from remote transport during 2019 Australian mega fire events

The 2019 Australian mega fires were unprecedented considering their intensity and consistency. There has been much research on the environmental and ecological effects of these mega fires, most of which focused on the effect of huge aerosol loadings and the ecological devastation. Sea land breeze (SLB) is a regional thermodynamic circulation closely related to coastal pollution dispersion, yet few have looked into how it is influenced by different types of aerosols transported from either nearby or remote areas. Mega fires provide an optimal scenario of large aerosol emissions. Near the coastal site of Brisbane Archerfield during January 2020, when mega fires were the strongest, reanalysis data from Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) showed that mega fires did release huge amounts of aerosols, making aerosol optical depth (AOD) of total aerosols, black carbon (BC) and organic carbon (OC) approximately 240 %, 425 % and 630 % of the averages in other non-fire years. Using 20 years' wind observations of hourly time resolution from a global observation network managed by the National Oceanic and Atmospheric Administration (NOAA), we found that the SLB day number during that month was only 4, accounting for 33.3 % of the multi-years' average. The land wind (LW) speed and sea wind (SW) speed also decreased by 22.3 % and 14.8 % compared with their averages respectively. Surprisingly, fire spot and fire radiative power (FRP) analysis showed that heating effects and aerosol emission of the nearby fire spots were not the main causes of the local SLB anomaly, while the remote transport of aerosols from the fire centre was mainly responsible for the decrease of SW, which was partially offset by the heating effect of nearby fire spots and the warming effect of long-range transported BC and CO2. The large-scale cooling effect of aerosols on sea surface temperature (SST) and the burst of BC contributed to the slump of LW. The remote transport of total aerosols was mainly caused by free diffusion, while the large-scale wind field played a secondary role at 500 m. The large-scale wind field played a more important role in aerosol transport at 3 km than at 500 m, especially for the gathered smoke, but free diffusion remained the major contributor. The decrease of SLB speed boosted the local accumulation of aerosols, thus making SLB speed decrease further, forming a positive feedback mechanism.

Application TAPM-AERMOD system model to study impacts of thermal power plants in SouthEast and SouthWest areas to the air quality of HCMC: current status and according to Vietnam power planning VII toward 2030

Vietnam’s urban areas have faced serious environmental pollution issues, including water pollution, municipal waste, and air pollution. Vietnam’s real gross domestic product (GDP) has been experiencing positive growth for the past five years since 2016. And in 2019, Vietnam’s real GDP increased by 7.02% compared to the previous year. To maintain the growth rate, there is a huge amount of electricity required, not accounting for the other sectors. Thermal power plants generate more than 50% of total electricity in Vietnam, therefore, it is said that coal-fired power plants have been the major sources of air emissions and caused a serious impact on the environment. Recently air pollution is a hot issue in Ho Chi Minh City (HCMC), the air quality is being polluted by PM2.5, O3, CO, NO2, and TSP. Despite that, the neighboring areas of the city will install more coal-fired power plants, threatening to degrade the quality of the environment. Therefore, the objectives of this study are (i) Modeling the impacts of thermal power plants in SouthEast and SouthWest areas on the air quality of HCMC for two scenarios (current status in 2019 and future according to Power planning VII (adjusted) toward 2030); And (ii) Develop interprovincial air quality protection solutions. The research applied the TAPM model for meteorological modeling and AERMOD model for air pollution dispersion. The annual average PM2.5 concentration in the study area was approximately 0.121 μg/m3 and the highest concentration at a location close to Vinh Tan thermal power center with 8.61 μg/m3. NO2 the annual average concentration from power plants in 2020 and 2030 blows to HCMC and contributes to HCMC’ air quality only 0.01 and 0.03 μg/m3, respectively. The 24 hours average concentration of SO2 from power plants in 2030 blows to HCMC and contributes to HCMC’ air quality of 10 μg/m3. The 24 hours average SO2 levels of HCMC in 2030 is 39.2 μg/m3, higher than WHO’s guideline (20 μg/m3). Currently, air pollution in HCMC is polluted by PM2.5, SO2, and NO2 and cause bad effect to public health. However, in the future with the contribution of 33 thermal power plants under intercity/provinces air pollution dispersion, air pollution HCMC will be worse and affect public health. Air pollution HCMC will be a huge impact on HCMC’s public health in the future due to the contribution of 33 thermal power plants under intercity/provinces air pollution dispersion. The paper developed 7 main mitigation measures to reduce the impacts of air pollution from the power plan and reduce the impacts of air pollution on HCM’s public health. The measures are focused on using clean fuel, advanced technology, and controlling trans-provincial air pollution.

Balikpapan’s wind analysis to determine air quality monitoring point to support smart environment monitoring system

In this industrial era, air pollution become a concerning problem since it can cause some respiratory problems. One of the air pollutions was Sulphur dioxide which dilutes fast in atmospheric water vapor resulting in acid rain which can affect the organism. Thus, in this research, we study the probability of the receptor’s location according to wind direction, as the preliminary information on deciding monitoring point. The meteorological data were obtained from Balikpapan’s Agency for Meteorological, Climatological, and Geophysics. The wind data was then plotted using a wind rose plot program called WRPLOT. Afterward, the dominant wind speed and direction will then be analyzed using google earth to know which point will be affected by the pollution dispersion from the chimney in Balikpapan. The results show that wind in Balikpapan throughout 2020 mostly blew from Southwest to Northeast Direction. Thus, the most probable receptor locations were open green spaces with no settlement around. This will have less impact on human health. Nevertheless, further research can be conducted to know better the on-air dispersion model around the power plant, how the green plant will be suffered from this air pollution, and how this pollution will affect the workers around it.

Air pollution dispersion modeling of runway and apron at Sam Ratulangi international airport

Air pollution generated from airport activities has become public concern and the subject of more rigorous government regulations. The Airport Operators are stipulated to control the pollution and for the accountability of air quality that might affect public health. The main objective of this study is to establish a model for the distribution of air pollutants and to predict their concentrations generated by the runway and apron operations at Sam Ratulangi International Airport (Manado) until 2024, in accordance with the airport expansion program. The data was collected in the airport surrounding area in 2018, while the climate data over a span of 10 years, from 2009 to 2018, was obtained from Sam Ratulangi Meteorological Station. The modeling on dispersion of air pollutant gases was developed by the Gaussian Plume Equation. The simulation was performed using AERMOD software, and the results visualized by GIS software. AERMOD software was recommended by the US-EPA to predict the impact of air pollutants. The results predicted that the maximum concentrations of NOx; HC; and CO generated by runway activities modeling in 2024 were 250 μg.m-3; 6.4 μg.m-3; and 87 μg.m-3 respectively. The results also predicted that the maximum concentrations of NOx; CO; and PM10 due to apron operational activities in 2024 were 260 μg.m-3; 892 μg.m-3; and 2.5 μg.m-3 respectively. The model predicted that in 2024 the air pollution at Sam Ratulangi International Airport will remain under the limit as defined in Indonesian Government Regulation No. 22 of 2021. To mitigate the future increase in air emissions due to the increase in airport capacity, the recommendation were proposed in the several areas, which were including operation management, technology, policies and airport regulations, as well as the provision of green area.

Observed slump of sea land breeze in Brisbane under the effect of aerosols from remote transport during 2019 Australia mega fire events

The 2019 Australia mega fires were unprecedented considering its intensity and consistency. There have been many researches on the environmental and ecological effects of the mega fires, most of which focused on the effect of huge aerosol loadings and the ecological devastation. Sea land breeze (SLB) is a regional thermodynamic circulation closely related to coastal pollution dispersion yet few have looked into how it is influenced by different types of aerosols transported from either nearby or remote areas. Mega fires provide an optimal scenario of large aerosol loadings. Near the coastal site of Brisbane Archerfield during January in 2020 when mega fires were the strongest, reanalysis data from Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) showed that mega fires did release huge amounts of aerosols, making aerosol optical depth (AOD) of total aerosols, Black Carbon (BC) and Organic Carbon (OC) approximately 240 %, 425 %, 630 % of the averages of other non-fire years. Using 20 years’ wind observations of hourly time resolution from global observation network managed by National Oceanic and Atmospheric Administration (NOAA), we found that SLB day number during that month was only four, accounting for 33.3 % of the multi-years’ average. The land wind (LW) speed and sea wind (SW) speed also decreased by 22.3 % and 14.8 % compared with their averages respectively. Surprisingly, fire spot and fire radiative power (FRP) analysis showed that heating effect and aerosol emission of the nearby fire spots were not the main cause of local SLB anomaly while the remote transport of aerosols from the fire center was mainly responsible for the decrease of SW, which was partially offset by the heating effect of nearby fire spots and warming effect of long-range transported BC and CO2. The large scale cooling effect of aerosols on sea surface temperature (SST) and the burst of BC contributed to the slump of LW. The remote transport of total aerosols was mainly caused by free diffusion while large scale wind field played a secondary role at 500 m. Large scale wind field played a more important role in aerosol transport at 3 km than at 500 m, especially for the gathered smoke, but free diffusion remained the major contributor. The decrease of SLB speed boosted the local accumulation of aerosols, thus further made SLB speed decrease, forming a positive feedback mechanism.

Urban Heat Island and Its Interaction with Heatwaves: A Review of Studies on Mesoscale

With rapid urbanization, population growth and anthropogenic activities, an increasing number of major cities across the globe are facing severe urban heat islands (UHI). UHI can cause complex impacts on the urban environment and human health, and it may bring more severe effects under heatwave (HW) conditions. In this paper, a holistic review is conducted to articulate the findings of the synergies between UHI and HW and corresponding mitigation measures proposed by the research community. It is worth pointing out that most studies show that urban areas are more vulnerable than rural areas during HWs, but the opposite is also observed in some studies. Changes in urban energy budget and major drivers are discussed and compared to explain such discrepancies. Recent studies also indicate that increasing albedo, vegetation fraction and irrigation can lower the urban temperature during HWs. Research gaps in this topic necessitate more studies concerning vulnerable cities in developing countries. Moreover, multidisciplinary studies considering factors such as UHI, HW, human comfort, pollution dispersion and the efficacy of mitigation measures should be conducted to provide more accurate and explicit guidance to urban planners and policymakers.

Simulation of wastewater dispersion of recycling scrap paper from Muc Son Paper factory to the downstream Chu river

This research simulates and forecasts the area as well as the level of pollution dispersion of Muc Son Paper Factory’s wastewater to the downstream of Chu River under two scenarios: Scenario 1 - wastewater treatment system is broken; treatment efficiency is equal to 0; Scenario 2 - wastewater treatment system is working with its designed capacity. The applied results of the MIKE 11 model show that: the impacted area from the plant’s discharge is 0.2 km upstream and 2 km downstream of the confluence point. The simulation results under Scenario 1 show TSS, BOD5 and COD contents being 18.3–35.7 mg/L, 8.3–17.2 mg/L and 12.2–23.7 mg/L, respectively, negatively affect the water environment downstream of Chu river. The results are then compared with measured data to confirm the reliability of the model. This research is a scientific and practical basis for the Muc Son Paper factory to operate the wastewater treatment system and manage the water quality output to ensure environmental regulations.

Impact of Ventilation Strategy on the Transmission of Outdoor Pollutants into Indoor Environment Using CFD

The transition to remote working due to the pandemic has accentuated the importance of clean indoor air, as people spend a significant portion of their time indoors. Amongst the various determinants of indoor air quality, outdoor pollution is a significant source. While conventional studies have certainly helped to quantify the long-term personal exposure to pollutants and assess their health impact, they have not paid special attention to the mechanism of transmission of pollutants between the two environments. Nevertheless, the quantification of infiltration is essential to determine the contribution of ambient pollutants in indoor air quality and its determinants. This study evaluates the transmission of outdoor pollutants into the indoor environment using 3D computational fluid dynamics modelling with a pollution dispersion model. Naturally ventilated buildings next to an urban canyon were modelled and simulated using Ansys Fluent and validated against wind tunnel results from the Concentration Data of Street Canyons database. The model consisted of two buildings of three storeys each, located on either side of a road. Two line-source pollutants were placed in the street, representing traffic emissions. Three internal rooms were selected and modelled on each floor and implemented with various ventilation strategies. Results indicate that for a canyon with an aspect ratio of 1, indoor spaces in upstream buildings are usually less polluted than downstream ones. Although within the canyon, pollution is 2–3 times higher near the upstream building. Cross ventilation can minimise or prevent infiltration of road-side pollutants into indoor spaces, while also assisting in the dispersion of ambient pollutants. The critical configuration, in terms of air quality, is single-sided ventilation from the canyon. This significantly increases indoor pollutant concentration regardless of the building location. The study reveals that multiple factors determine the indoor–outdoor links, and thorough indexing and understanding of the processes can help designers and urban planners in regulating urban configuration and geometries for improved indoor air quality. Future works should look at investigating the influence of indoor emissions and the effects of different seasons.