The Sundarbans is the world’s most extensive natural mangrove forest and home to various natural resources. The population in the vicinity has increased, causing more dependency on the resources of the Sundarbans. The increasing industrialization, urbanization, aquaculture, intensive agricultural practices, seaports, tourism facilities, and so on in the peripheral areas of the Sundarbans have made significant changes in the surrounding and upstream land uses of the Sundarbans. This situation may have detrimental influences on the ecosystem components of the Sundarbans. Therefore, it is highly demanded to prepare a piece of baseline information or database of different sources of pollution and their present status in the various components of the Sundarbans. This effort helps to identify issues and concerns, determine the key elements of the ecosystem to monitor the level or overall quality of the Sundarbans ecosystem. The present study systematically collects the potential sources of pollution, types, and current levels in the ecosystem components of the Sundarbans using academic databases, libraries, and online resources. Discharge of industrial waste into water, soil and air, heavy metal pollution, use of agrochemicals, oil (refined and crude) pollution, plastic materials from urban areas, and tourism are the major issues and concerns related to the sustainability of the Sundarbans ecosystem. The air quality of the Sundarbans is in good condition with 0 - 50 AQI of Bangladesh. While BOD, COD, TDS, TSS varied from 2.0 to 3.8 mg/L, 21.6 to 416 mg/L, 146.9 to 24,100 mg/L and 54 to 155 mg/L, respectively. Soil EC, organic carbon, total nitrogen, and total phosphorus ranged from 3.01 - 5.82 mS/cm, 1.41% - 2.69%, 0.51 - 1.05 mg/g, and 0.32 - 0.51 mg/g respectively. The air, water and soil quality parameters varied with the sites and seasons and not much at the state of contamination. Indeed, we must pay much attention to the Sundarbans’ air, water and soil quality with the massive and progressive change of the ne
Air pollution is one of the most challenging environmental issues in the world.China has achieved remarkable success in improving air quality in last decade as a result of aggressive air pollution control policies.However,the average fine particulate matter(PM2.5)concentration in China is still about six times of the World Health Organization(WHO)Global Air Quality Guidelines(AQG)and causing significant human health risks.Extreme emission reductions of multiple air pollutants are required for China to achieve the AQG.Here we identify the major challenges in future air quality improvement and propose corresponding control strategies.The main challenges include the persistently high health risk attributed to PM2.5 pollution,the excessively loose air quality standards,and coordinated control of air pollution,greenhouse gases(GHGs)emissions and emerging pollutants.To further improve air quality and protect human health,a health-oriented air pollution control strategy shall be implemented by tightening the air quality standards as well as optimizing emission reduction pathways based on the health risks of various sources.In the meantime,an“oneatmosphere”concept shall be adopted to strengthen the synergistic control of air pollutants and GHGs and the control of non-combustion sources and emerging pollutants shall be enhanced.
Wildfire episodes have become more frequent and severe in recent years.1 Record-breaking fires devastated the Arctic,Amazon,and Australia in 2019–2020.This year,fires began in Canada in May and lasted for several months,resulting in an area burned of 16.5 million hectares by early September.This size is 6–7 times the annual fire area for a normal year in Canada.The favorable fire weather for burning and spread lasted for months(https://cwfis.cfs.nrcan.gc.ca/maps/fw).Furthermore,most Canadian fires occur in remote regions far from firefighting facilities,causing fire extinction to be difficult.Unfortunately,such“unprecedented”fire events occurred routinely in boreal regions between 2020 and 2023,although the locations varied from year to year(Figure 1).
Aerosol ammonium(NH_(4)^(+)),mainly produced from the reactions of ammonia(NH_(3))with acids in the atmosphere,has significant impacts on air pollution,radiative forcing,and human health.Understanding the source and formation mechanism of NH_(4)^(+)can provide scientific insights into air quality improvements.However,the sources of NH_(3)in urban areas are not well understood,and few studies focus on NH_(3)/NH_(4)^(+)at different heights within the atmospheric boundary layer,which hinders a comprehensive understanding of aerosol NH_(4)^(+).In this study,we perform both field observation and modeling studies(the Community Multiscale Air Quality,CMAQ)to investigate regional NH_(3)emission sources and vertically resolved NH_(4)^(+)formation mechanisms during the winter in Beijing.Both stable nitrogen isotope analyses and CMAQ model suggest that combustion-related NH_(3)emissions,including fossil fuel sources,NH_(3)slip,and biomass burning,are important sources of aerosol NH_(4)^(+)with more than 60%contribution occurring on heavily polluted days.In contrast,volatilization-related NH_(3)sources(livestock breeding,N-fertilizer application,and human waste)are dominant on clean days.Combustion-related NH_(3)is mostly local from Beijing,and biomass burning is likely an important NH_(3)source(~15%–20%)that was previously overlooked.More effective control strategies such as the two-product(e.g.,reducing both SO_(2)and NH_(3))control policy should be considered to improve air quality.