Air pollutant emission characteristics and HYSPLIT model analysis during heating period in Shenyang, China

New evidence of unequal contribution to health burden reshaping air pollution control in waste-to-energy plants

Waste-to-energy (WTE) incineration has been long argued for the emission of hazardous flue gas pollutants (FGPs), while the contribution to health burden of individual components is ambiguous, resulting empirical control measures. We constructed a comprehensive framework to assess the health burden by monetizing premature mortalities, combining nine kinds of regulated FGPs from WTE plants. NOx and SO2 were identified as the main contributors to health risk, accounting for around 88.87 % and 6.97 % respectively in 2020. The annual social cost of mortalities (SCM) increased from USD 6.09 billion in 2010 to USD 13.60 billion in 2015, and to USD 16.71 billion in 2020, related to the surge in WTE capacity, which grew 10-fold over the past decade. The SCM per ton of municipal solid waste, however, significantly decreased from 329 USD/t in 2010 to 213 USD/t in 2015, and to 88 USD/t in 2020, due to updating of the standards and technological advances, pushing the emission factors down by 33.75-98.63 %. SCM will be continuously mitigated by the tightened emission limits, with the greatest benefits seen in a reduction of up to 50 % in NOx to 80 mg/m3 by selective catalytic reduction and selective non-catalytic reduction. Coastal regions were recommended as a high priority for further control, on account of their greater population density, higher economic level, and greater WTE capacity, which made up 60-71 % of total reduction benefits. These findings provide data support and recommendations for policymakers and stakeholders to mitigate FGPs emissions to efficiently reduce the health risk of WTE plants.

Assessment of Brick Kilns' contribution to the air pollution of Lahore using air quality dispersion modeling

Lahore (31.320°N; 74.220°E), Pakistan's second-largest city with a population of 13 million, is considered among the most polluted cities in the world and the most polluted city in Pakistan. We estimated emissions from one of the major sources (brick kilns) and analysed the corresponding impacts on regional air quality. The distribution of pollutants from the brick kilns in Lahore was calculated via a steady-state model (Sutton's model) and a dynamic model (Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model version 4). Sutton's model was used to determine the dispersion of a hypothetical pollutant in the vicinity of multiple brick kilns in a steady state. HYSPLIT was employed to compute the dynamic distribution of pollutant concentrations (24 h) for six pollutants using meteorological data (GDAS) and published emission rates of pollutants. The results for November-February 2021-2022 indicated that only SO2 exceeded all the WHO, NEQS, and NAAQS standards in the vicinity of the kilns. A comparison of the modeled concentrations from brick kiln emissions in the middle of Lahore with air pollution data for that area indicated significantly higher pollution levels derived from other pollution sources. It was concluded that in addition to SO2, brick kilns do not contribute significantly to air pollution in a substantial part of the city. However, as the city expands towards the areas where most of the brick kilns are located, this situation will change. These findings underscore the need for strategic urban planning and cleaner kiln technologies to mitigate future air quality impacts.

Wildfires Increase Concentrations of Hazardous Air Pollutants in Downwind Communities

Due in part to climate change, wildfire activity is increasing, with the potential for greater public health impact from smoke in downwind communities. Studies examining the health effects of wildfire smoke have focused primarily on fine particulate matter (PM2.5), but there is a need to better characterize other constituents, such as hazardous air pollutants (HAPs). HAPs are chemicals known or suspected to cause cancer or other serious health effects that are regulated by the United States (US) Environmental Protection Agency. Here, we analyzed concentrations of 21 HAPs in wildfire smoke from 2006 to 2020 at 309 monitors across the western US. Additionally, we examined HAP concentrations measured in a major population center (San Jose, CA) affected by multiple fires from 2017 to 2020. We found that concentrations of select HAPs, namely acetaldehyde, acrolein, chloroform, formaldehyde, manganese, and tetrachloroethylene, were all significantly elevated on smoke-impacted versus nonsmoke days (P < 0.05). The largest median increase on smoke-impacted days was observed for formaldehyde, 1.3 μg/m3 (43%) higher than that on nonsmoke days. Acetaldehyde increased 0.73 μg/m3 (36%), and acrolein increased 0.14 μg/m3 (34%). By better characterizing these chemicals in wildfire smoke, we anticipate that this research will aid efforts to reduce exposures in downwind communities.

Effects of stubble burning and firecrackers on the air quality of Delhi

Every year at the onset of winter season (October-November), crop residue/parali/stubble burning starts in Punjab and Haryana, leading to heavy air pollution in Delhi, and adversely affecting human and environmental health. During this time, the combination of unfavourable meteorological conditions, additional emissions from stubble burning, and firework activities in this area causes the air quality to further deteriorate. In this study, we have attempted to understand the influence of parali and firecracker incidents on air pollutants' variability over Delhi during the last three years (2020 to 2022). For this purpose, daily average particulate matter and gaseous pollutants data were fetched from the Central Pollution Control Board (CPCB), and daily total fire counts and fire radiative power (FRP) data were retrieved from NASA's Fire Information for Resource Management System (FIRMS). A bigger area of severe burning is suggested by higher FRP values and higher fire counts in the middle of November in all the years considered. Three years satellite-based FIRMS data over Punjab and Haryana show the highest number of active fire counts in 2021 (n = 80,505) followed by 2020 (n = 75,428), and 2022 (n = 49,194). More than 90% parali burning incidents were observed in Punjab state only despite the considerable variability in numbers among the years. The significant effect of parali burning was seen on pollutant concentration variability. As the number of fire count increases or decreases in Punjab and Haryana, there is a corresponding increase or decrease in the particulate matter concentration with a time lag of few days (1 to 2 days). The trend in backward air mass trajectories suggests that the variable response time of pollutants' concentration is due to local and distant sources with different air mass speeds. Our estimates suggest that stubble burning contributes 50-75% increment in PM2.5 and 40 to 45% increase in PM10 concentration between October and November. A good positive correlation between PM2.5, PM10, NOX, and CO and fire counts (up to 0.8) suggests a strong influence of stubble burning on air quality over Delhi. Furthermore, the firecracker activities significantly increase the concentration of particulate matter with ~100% increment in PM2.5 and ~55% increment in PM10 mass concentrations for a relatively shorter period (1 to 2 days).

An assessment of aerosol optical depth over three AERONET sites in South Africa during the year 2020

It is important to notice that the world health organization (WHO) on  the 11th of March 2020,  declared COVID-19 a global pandemic and in response governments around the world introduced lockdowns that restricted human and traffic movements including South Africa. This pandemic resulted in a total lockdown from 26 March until 16 April 2020 in South Africa with expected  decrease in atmospheric aerosols. In this present study,  the aerosol optical depth (AOD) over Southern Africa based on ground-based remotely sensed data derived from three AERONET sites (Durban, Skukuza and Upington) during 2020 were used to detrermine the restriction resopnse on atmospheric aerosol pollution  The study used data from 2019, 2018 and 2017  as base years. The AERONET derived data was complemented with the HYSPLIT Model and NCEP/NCAR Reanalysis data. The study findings show that peak increase of AOD corresponds to Angstrom exponent (AE) enhancement for two sites Durban and Skukuza during winter (JJA) while the Upington site showed a different trend where peak AOD were observed in spring (SON). The study also observed the influence of long transport airmasses particularly those originating from the Atlantic and Indian ocean moreso for the Durban and Skukuza sites (summer and autumn) thus these sites received fresh marine aerosols however this was not the case for Upington which fell under the influence of short-range inland airmasses and was likely to receive anthropogenic and dust aerosols. The major results  suggest that the lockdowns did not translate into a significant decrease in AOD levels compared to previous immediate years. The results has presented restriction response of AOD over South Africa but additional analysis is required using more locations to compare results.

State of ambient air quality in a low-income urban settlement of South Africa

Air pollution remains one of the leading global environmental-health challenges the world is facing today, particularly within urban environments. amidst the COVID-19 pandemic, air pollution has been brought back into the spotlight as both attack the human respiratory systems. The purpose of the study was to investigate the quality of ambient air in a low-income urban settlement of Jabavu located within the City of Johannesburg during the year 2018. Air pollution and meteorological data were gathered from the South African Air Quality System network. The study focused on three pollutants namely PM₁₀, SO₂ and O₃. Findings were that the seasonal ambient mean concentrations for PM₁₀ in summer was (28.99 µg/m³), autumn (33.32 µg/m³), winter (61.71 µg/m³) and spring (48.44 µg/m³). On the other hand, the seasonal ambient mean concentrations for SO₂ was summer (4.45ppb), autumn (3.19ppb), winter (5.65ppb) and spring (3.54ppb). The O₃ seasonal ambient mean concentrations were summer (40.97ppb), autumn (21.01ppb), winter (15.90ppb) and spring (33.59ppb). Furthermore, the study observed that in summer, winter and spring the dominant long-range transport air masses originated from the South Atlantic Ocean, Madagascar Island-India Ocean and the Indian Ocean while in autumn the dominant air masses are short-range inland air masses. For SO₂ and PM_10, ambient concentrations were found to be more problematic during winter; while for O₃ substantial levels were unexpectedly recorded in summer. When analysing the diurnal profiles of PM₁₀, SO₂ and O_3, each of these pollutants revealed a unique distribution pattern, which, despite having seasonal variance, was consistent throughout the year. For instance, irrespective of the season, PM₁₀ mostly peaked in the mornings and evenings; meanwhile SO₂ and O₃ often spiked during the midday and mid-afternoon, respectively. These findings indicate that air quality within this low-income settlement is poor. To improve air quality within low-income settlements there is a need for a shift from reliance on solid fuels to cleaner energy sources such as LP gas, biogas and solar accompanied by an increase in community awareness about air quality issues. This study contributes to knowledge building within the air quality monitoring scientific community while for policymakers it assists in policy formulation to enable air quality management.

Pollution Characteristics and Health Risk Assessment of VOCs in Jinghong

In order to investigate the seasonal variation in chemical characteristics of VOCs in the urban and suburban areas of southwest China, we used SUMMA canister sampling in Jinghong city from October 2016 to June 2017. Forty-eight VOC species concentrations were analyzed using atmospheric preconcentration gas chromatography–mass spectrometry (GC–MS), Then, regional VOC pollution characteristics, ozone formation potentials (OFP), source identity, and health risk assessments were studied. The results showed that the average concentration of total mass was 144.34 μg·m−3 in the urban area and 47.81 μg·m−3 in the suburban area. Alkanes accounted for the highest proportion of VOC groups at 38.11%, followed by olefins (36.60%) and aromatic hydrocarbons (25.28%). Propane and isoprene were the species with the highest mass concentrations in urban and suburban sampling sites. The calculation of OFP showed that the contributions of olefins and aromatic hydrocarbons were higher than those of alkanes. Through the ratio of specific species, the VOCs were mainly affected by motor vehicle exhaust emissions, fuel volatilization, vegetation emissions, and biomass combustion. Combined with the analysis of the backward trajectory model, biomass burning activities in Myanmar influenced the concentration of VOCs in Jinghong. Health risk assessments have shown that the noncarcinogenic risk and hazard index of atmospheric VOCs in Jinghong were low (less than 1). However, the value of the benzene cancer risk to the human body was higher than the safety threshold of 1 × 10−6, showing that benzene has carcinogenic risk. This study provides effective support for local governments formulating air pollution control policies.

Spatial Characteristics and Regional Transmission Analysis of PM2.5 Pollution in Northeast China, 2016-2020

Northeast China is an essential industrial development base in China and the regional air quality is severely affected by PM_2.5 pollution. In this paper, spatial autocorrelation, trajectory clustering, hotspot analysis, PSCF and CWT analysis are used to explore the spatial pollution characteristics of PM_2.5 and determine the atmospheric regional transmission pattern for 40 cities in Northeast China from 2016 to 2020. Analysis of PM_2.5 concentration characteristics in the northeast indicates that the annual average value and total exceedance days of PM_2.5 concentration in Northeast China showed a U-shaped change, with the lowest annual average PM_2.5 concentration (31 μg/m³) in 2018, decreasing by 12.1% year-on-year, and the hourly PM_2.5 concentration exploding during the epidemic lockdown period in 2020. A stable PM_2.5 pollution band emerges spatially from the southwest to Northeast China. Spatially, the PM_2.5 in Northeast China has a high degree of autocorrelation and a south-hot-north-cool characteristic, with all hotspots concentrated in the most polluted Liaoning province, which exhibits the H-H cluster pattern and hotspot per year. Analysis of the air mass trajectories, potential source contributions and concentration weight trajectories in Northeast China indicates that more than 74% of the air mass trajectories were transmitted to each other between the three heavily polluted cities, with the highest mean value of PM_2.5 pollution trajectories reaching 222.4 μg/m³, and the contribution of daily average PM_2.5 concentrations exceeding 60 μg/m³ within Northeast China. Pollution of PM_2.5 throughout the Northeast is mainly influenced by short-range intra-regional transport_, with long-range transport between regions also being an essential factor; organized integration is the only fundamental solution to air pollution.