PICO
This session at the European Geosciences Union (EGU) invites submissions on observational and modeling studies of emerging air pollution emissions and chemistry, including their climate and health impacts.
Urban air pollution in the Anthropocene increasingly reflects mixed emissions from both traditional outdoor sources and emerging indoor technological activities. Among these, printing and photocopying shops constitute important yet understudied microenvironments within academic institutions such as University of Delhi, where students and informal-sector workers experience routine exposure to diverse pollutants in confined spaces. To characterise pollutant composition, indoor chemistry, and associated health implications in these settings, we monitored ozone (O₃), PM₂.₅, PM₁₀ and NO₂ across three contrasting printing environments in University of Delhi: an open-front photocopy shop in Hindu College (North Campus), a semi-enclosed photocopy room in South Campus, and a closed indoor flex-printing facility in commercial area nearby (Malka Ganj, Delhi). Continuous measurements were conducted during the monsoon season (1 August–30 September 2025) at 15-minute intervals between 11:00–17:00, alongside temperature and relative humidity observations.
Ozone concentrations remained consistently low (16–22 ppb) across all microenvironments, influenced by the modest O₃-generation capacity of photocopiers and monsoon-season conditions that favour rapid ozone scavenging via humid surfaces and co-emitted NO. In contrast, pronounced multi-pollutant interactions emerged in the semi-enclosed and enclosed settings. Strong O₃–NO₂ correlations (r = 0.75 and 0.72, respectively) highlight the role of shared machine-driven emissions coupled with restricted dilution. Likewise, the very high PM₂.₅–PM₁₀ correlations (r = 0.93 in the semi-enclosed shop; r = 0.80 in the flex-printing room) confirm distinct particulate-generation mechanisms: fine-particle–rich emissions from heated toner units in photocopier rooms and coarse, solvent-associated particulate bursts from flex-printing operations. The enclosed flex environment exhibited the largest PM excursions, marking it as the most pollution-intensive indoor printing microenvironment.
A structured worker survey revealed frequent symptoms (eye/throat irritation, cough, headaches, fatigue) and a lack of safety training for over 70% of operators. As most photocopy shops in Delhi operate in narrow, poorly ventilated galis, real-world exposures may exceed those observed in the monitored sites.
Collectively, these results demonstrate that microenvironmental design and ventilation strength fundamentally regulate indoor pollutant composition, chemical interactions, and human exposure risk. The findings emphasise the urgent need for ventilation-oriented design standards, emission-reduced printing technologies, and targeted occupational-health safeguards within densely populated institutional and urban commercial settings.
How to cite: Saxena, P., Suryanarayan, S., Sharma, R., Bali, R., and Singh, M.: Ozone and Multi-Pollutant Dynamics: Indoor Chemistry and Exposure Risks in Printing Environments in University Campus Area, Delhi, India, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-658, https://doi.org/10.5194/egusphere-egu26-658, 2026.
Elevated air pollution endangers the environment, climate, and human health, creating significant socioeconomic challenges. These pollutants harm ecosystems and exacerbate climate change. This study presents a comprehensive analysis of air quality variations across the Indo Gangetic Plain (IGP) of North India, examining spatial patterns of multiple pollutants across five distinct sub-regions over the four major seasons, namely, Summer, Monsoon, Post-monsoon, and Winter. Data across the major IGP monitoring stations reveal significant regional and seasonal differences in pollutant concentrations and Air Quality Index (AQI). The Middle-Indo Gangetic Plain (MIGP) exhibited the highest particulate matter concentrations (PM 10: 160.23±8.47 μg/m³, PM 2.5: 71.5±4.68 μg/m³), while the North Eastern region (NE) demonstrated the lowest levels (PM 10: 61.72±27.23 μg/m³, PM 2.5: 32.07±14.01 μg/m³). Notable variations were observed in gaseous pollutants, with the Lower-Indo Gangetic Plain (LIGP) showing the highest SO2 (18.55±4.68 μg/m³) concentrations. Major urban centers emerged as pollution hotspots with AQI values exceeding 175, while Aizawl in the cleaner and less populated northeast India maintained AQI below 42. These findings indicate a west-to-east pollution gradient with significant influence from local emission sources, topographical features, and weather conditions. The pronounced inter-regional differences over various seasons highlight the need for tailored air quality management strategies addressing region-specific pollution characteristics rather than uniform approaches across the entire IGP region.
How to cite: Srivastava, M. K., Chaudhary, A., Mehrotra, B. J., and Srivastava, A. K.: Spatiotemporal Distribution of Air Pollutants across Indo Gangetic Plain: A Multi-Regional Comparative Analysis, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-481, https://doi.org/10.5194/egusphere-egu26-481, 2026.
Urban air pollution represents a major environmental and public health issue, particularly in large metropolitan areas. This study presents an analysis of black carbon (BC) and particulate matter with an aerodynamic diameter smaller than 2.5 µm (PM2.5) concentrations in Bucharest, Romania, over the period 2022–2025, using a combination of on-site and mobile measurements. Field campaigns considered both short-term (about 10 days) and longer-term measurements, up to three months. The short-term field campaign, was carried out using a mobile laboratory that covered more than 1,500 km in August 2024. The city area was divided into three distinct zones—north-west, north-east, and south—with a specific route defined for each zone. Each route was travelled four times: once during night-time and three times during daytime on consecutive days. This data acquisition strategy ensured adequate statistical consistency and enabled the capture of both temporal and spatial variations in atmospheric BC and PM2.5 concentrations. The temporal variability of atmospheric pollutants was analysed based on data gathered in the long-term campaign performed at a location situated in the western part of the city, an area with high traffic. The results reveal significant spatial-temporal variability in BC and PM2.5 levels, strongly influenced by road traffic intensity, urban land-use characteristics, and time of day. Areas that exhibit elevated fine particulate pollution were identified within Bucharest. As an example, in 2022, close to the high traffic western area with traffic noise levels ranging from 40 dB (night-time) to about 75 dB (daytime), a mean PM2.5 concentration of about 35 µg m⁻³, and mean black carbon (BC) concentration of 11.38 ng m⁻³ in the ultrafine particles were measured. No significant changes were detected in PM2.5 and BC levels over time at that location, indicating a significant people chronic exposure. These elevated long-term concentrations support the role of road traffic as a major urban stressor by the combined exposure to air pollution and noise, both relevant for public health risk. Each field campaign was also meteorological characterized, in order to better understand the variations of PM2.5 and BC concentrations. During the mobile measurement campaign in summer 2024, the Bucharest area was characterized by a moderately deep atmospheric boundary layer (mean height ~850 m), favouring partial vertical mixing, while prevailing weak-to-moderate south-easterly winds (mean speed 2.6 m s⁻¹) suggest limited horizontal ventilation. Air temperatures ranging between 22 and 32 °C, combined with relatively low to moderate relative humidity (35–55%), indicate warm and generally dry conditions, conducive to thermal stress and potentially reduced dispersion of urban pollutants, especially during night-time stable periods. This is a typical meteorological condition for Bucharest summers.
Present study highlights the importance of integrating fixed and mobile measurements for a detailed assessment of urban atmospheric composition to further assess the population exposure to harmful atmospheric constituents, and provides relevant information to support air quality management strategies in Bucharest.
How to cite: Tudor, A., Scarlat, A., and Iorga, G.: Anthropogenic Impact on Atmospheric Composition over Bucharest, Romania: Insights from Multiple Field Campaigns (2022–2025), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4997, https://doi.org/10.5194/egusphere-egu26-4997, 2026.
Coastal industrial and urban regions in Europe host a substantial fraction of the population and economic activity, yet they remain highly vulnerable to particulate matter (PM) pollution episodes. Despite the implementation of air quality regulations, exceedances of PM10 and PM2.5 concentration thresholds persist, driven by the coexistence of dense emission sources and complex coastal atmospheric dynamics. In this study, pollution days (PDs) were analyzed over a four-year period (2018–2021) in the Greater Dunkirk Area, a coastal region influenced by multiple anthropogenic and marine sources. Spatial analyses indicate that PM2.5 pollution episodes are predominantly associated with regionally extended plumes, whereas PM10 episodes are more frequently linked to locally confined plumes, exhibiting marked seasonal variability. Detailed aerosol chemical characterization was conducted using SEM–EDX analysis on more than 23,000 individual particles collected during a one-year field campaign in 2021. The results reveal a highly heterogeneous particle population, largely dominated by sea-salt and carbonaceous aerosols, with fine particles enriched in secondary sulfur-containing species and coarse particles characterized by calcium-rich components. The particle mixing state index (χ) spans a wide range (0.5–0.9), reflecting a continuum between externally and internally mixed aerosols, strongly modulated by atmospheric ageing processes, pollutant recirculation, and turbulent mixing. Our findings demonstrate that neither local wind direction nor plume spatial extent alone adequately explains the observed chemical variability. Instead, the evolution of aerosol composition and mixing state is governed by fine-scale meteorological processes, including sea-breeze circulations and recirculation events, which critically influence pollutant dispersion and ageing. These results underscore the importance of integrating high-resolution single-particle chemistry with urban-scale meteorological dynamics in air quality assessments, particularly in complex coastal environments subject to multiple emission sources.
How to cite: Deguine, A., Waza, A., Ngagine, S., Flament, P., Augustin, P., Cazier, F., Dewaele, D., Dieudonne, E., Delbarre, H., Fourmentin, M., and Deboudt, K.: Particulate Matter Pollution Episodes in a Multisource Coastal Environment: Insights from Single-Particle Analysis and atmospheric dynamic, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10658, https://doi.org/10.5194/egusphere-egu26-10658, 2026.
Problem considered: Air pollution is a critical environmental health issue with profound impacts on vulnerable populations. Understanding the impact of ambient air pollution on adverse health outcomes and death rate is crucial for informing evidence-based interventions and policy measures to address this critical issue.
Methods: We analyzed secondary data on ambient air pollutants particulate matter (PM2.5 and PM10), nitrogen dioxide (NO2), sulphur dioxide (SO2) and ozone (O3) levels from 2018 to 2023 across all eight districts in New Delhi. Data were obtained from the Central Pollution Control Board (CPCB) and Delhi government databases. Health outcome indicators, including overall mortality rate, were assessed for associations with ambient air pollutant levels.
Results: Air pollutant levels across all districts of New Delhi were found to be highest during 2018–2019, followed by a decline in 2019–2021, likely due to the COVID-19 pandemic and related restrictions. Additionally, all pollutants showed positive associations with adverse health outcomes (mortality indices), with particularly strong links between SO2 and ozone in Delhi.
Conclusion: Our findings highlight a concerning association between ambient air pollution and adverse health outcomes in New Delhi. However, the findings should be interpreted with caution, as multiple confounding factors such as socioeconomic status, lifestyle, and healthcare access may also influence outcomes. More large-scale and long-term studies are needed to minimize these limitations and establish stronger causal relationships.
Keywords: Air Pollution, Particulate Matter, Death Rate, Mortality Indices
How to cite: Arora, T., Gautam, R., and Vasudevan, S.: Analysis trends of Environment pollutants (Ambient Air Pollution) and its adverse health effect in New Delhi over a period of 2018-2023, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1556, https://doi.org/10.5194/egusphere-egu26-1556, 2026.
Objective: Existing research suggests that vaccine antibody response can be attenuated by environmental factors, but limited studies have assessed the association with air pollutants. We hypothesize that air pollution exposure early in life can alter immune response in later childhood.
Methods: We obtained serum antibody levels of tetanus, diphtheria, and pertussis measured in vaccinated children ages 4-6 years from the Programming Research in Obesity, Growth, Environment and Social Stressors (PROGRESS) cohort in Mexico. We constructed 1-km2 fine particulate matter (PM2.5) and nitrogen dioxide (NO2) models over the Mexico City Metropolitan Area, which we geocoded to participants’ home addresses. We employed linear mixed-effects models to examine the association between early life exposure to PM2.5 and NO2, measured as averaged pollutants exposures in the first year of life, and log-transformed tetanus, diphtheria, and pertussis (Tdap) antibody levels in later childhood (ages 4-6). Models included random intercepts for participant and were adjusted for temperature, sex, child age at blood draw, maternal age at birth, BMI, and socioeconomic status.
Results: 299 children contributed to antibody levels at 4 years (n=287) and 6 years (n=12). We observed negative but imprecise associations with both pollutants. Per 1 µg/m3 increase in one-year postnatal PM2.5, Tdap antibody levels decreased by 3.47% (95%CI: -7.35, 0.57%), 3.37% (95%CI: -7.18, 0.60%), and 2.56% (95%CI: -6.93, 2.02%) respectively. Per 1 µg/m3 increase in one-year postnatal NO2, Tdap antibody levels decreased by 3.89% (95%CI: -7.22, -0.45%), 3.51% (95%CI: -6.81, -0.09%), and 1.93% (95%CI: -5.74, 2.04%) respectively.
Conclusion: We found preliminary evidence suggesting decreased antibody levels in response to postnatal PM2.5 and NO2 exposure, though not all results were significant. Additional work is necessary to explore associations for different types of routine vaccinations and at different critical time windows.
How to cite: He, M. Z., Yitshak-Sade, M., Kloog, I., Just, A. C., Lesseur, C., Quataert, S. A., Téllez-Rojo, M. M., Torres, L., Lamadrid, H., Berin, M. C., Wright, R. O., Jusko, T. A., and Colicino, E.: Fine particulate matter, nitrogen dioxide, and Tdap vaccine antibody levels in Mexican children, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6037, https://doi.org/10.5194/egusphere-egu26-6037, 2026.
Ozone in the upper troposphere (UT) is critical for maintaining radiative balance at the top of the atmosphere (TOA). This study utilizes CMIP6 simulations to investigate photochemical pathways influencing ozone production in the UT during the Asian summer monsoon (ASM). We analyze the impact of convectively transported ozone precursors like nitrogen oxides (NOx), non-methane volatile organic compounds (NMVOCs), and carbon monoxide (CO) on the sensitivity of ozone formation over the Asian region in the UT. Our results show an increase of ozone in the UT by ~70% in the present-day compared to the pre-industrial era. This excess ozone is photochemically produced due to the elevated levels of NOx and CO in the UT, along with its direct convective transport from the boundary layer. Changes in formaldehyde (HCHO), a proxy for VOCs, are negligible in the UT. Analysis of ozone in relation to its precursors (HCHO, CO, and NO2) suggests that the UT is primarily NOx-limited, and ozone production follows the NOx-CO-O3 pathway. The UT ozone changes due to increasing ozone precursor emissions affect the radiative balance by exerting a positive ozone radiative effect at the TOA over the ASM anticyclone region. These findings indicate that suitable emission control strategies must be formulated to reduce NOx and CO emissions for limiting ozone enhancement in the UT
How to cite: Roy, C.: Sensitivity of upper tropospheric ozone to anthopogenic emissions during the Asian summer monsoon, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-607, https://doi.org/10.5194/egusphere-egu26-607, 2026.
Pollution challenges in India intensify during the post-monsoon period, particularly across the Indo-Gangetic Plain, where multiple emission sources intersect with adverse meteorological conditions to elevate particulate matter concentrations. This study investigates PM2.5 variations in Delhi-National Capital Region (NCR) during October-November of 2024 and 2025, with specific focus on the influence of crop-residue burning in Punjab and Haryana, local firecracker emissions, and temperature-driven atmospheric processes.
In 2024, a total of 779 stubble-burning incidents were detected between 1st to 12th October in Punjab and Haryana, coinciding with days that recorded high PM2.5 levels in Delhi-NCR. Satellite-based Fire Radiative Power (FRP) signals and air-mass back-trajectory analyses further validated the long-range transport of smoke plumes into the NCR. In contrast, severe flooding in 2025 in large parts of Punjab and pockets of Haryana resulted in a 77.5% decline in fire incidents during this period. This created a unique natural experiment to assess Delhi’s pollution baseline under minimal agricultural burning influence. Correspondingly, Delhi’s seasonal average PM2.5, reduced by 15.5%, highlighting the substantial contribution of transported biomass burning aerosols to regional air quality degradation.
However, despite significantly fewer regional stubble burning fire events, Delhi-NCR continued to experience notable PM2.5 spikes. Analysis indicates these increases in PM concentration were primarily driven by local emissions such as vehicular exhaust, road dust resuspension, refuse burning, episodic firecracker bursts around festive periods, construction and demolition activities. Additionally, secondary aerosol formation, particularly the conversion of NOx to nitrate under high humidity and low temperatures, contributed to elevated pollution loads.
Meteorological conditions further intensified pollution build-up in this region. Significant night-time temperature dips, shallow planetary boundary layers heights, and low wind speeds limited vertical mixing and hindered pollutant dispersion, causing pollutants to remain trapped near the surface.
The findings demonstrate that early-winter PM2.5 levels in Delhi-NCR are shaped by a complex interplay of transboundary smoke transport, persistent local emissions, and temperature-driven atmospheric processes that favour pollutant accumulation.
How to cite: Balyan, P., Kumar, A., and Dhaka, S. K.: Coupled Emission-Meteorology Controls on Early-Winter PM2.5 in Delhi-NCR Under Variable Biomass-Burning Regimes, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-672, https://doi.org/10.5194/egusphere-egu26-672, 2026.
Black carbon (BC) is known as a pollutant that poses serious risks to both the climate system and human health. The Southeast Asia region relies heavily on fossil fuels, and experiences frequent biomass burning that contributes significantly to BC emissions, yet research on BC measurements remains limited. To address these knowledge gaps, the present study aims to investigate the BC levels at two sites in Peninsular Malaysia, apportion the potential sources, and estimate the associated human health risks from BC exposure. The measurement campaign was conducted from August to November 2024 at Putrajaya and April to May 2025 at Johan Setia, Klang respectively. Real-time measurements of aerosol light absorption were continuously obtained using a AE33 aethalometer. The measured mean equivalent BC mass concentrations of 4.61 ± 1.75 g m-3 and 2.53 ± 0.75 g m-3 were observed in Johan Setia and Putrajaya, respectively. Johan Setia records higher BC concentrations due to multiple local emission sources from traffic, industries, residential, agricultural and commercial activities. BC from fossil fuel (BCff) dominated both sampling sites throughout the study period with several irregular localized peak episodes. Daily variations in BC concentrations reflect the critical contributions of traffic emissions during weekdays. A well-planned township like Putrajaya exhibits lower BC emissions, with consistent patterns indicating that light-duty vehicles are the primary source, reflecting its role as a government administrative and residential township. Elevated BCff were observed from midnight to early morning at Johan Setia, driven by emissions from nearby industrial facilities, power stations and heavy-duty vehicles operate at night because the position of the site lies along the main route connecting Klang to Port Klang, one of Malaysia’s busiest seaports. In addition, increasing trends of BC concentrations from biomass burning (BCbb) were prevalent from late evening until night at Johan Setia, likely due to the burning of agricultural residues by the residents. The BC index at both sites shows a dominant of the satisfactory category, with BC concentrations ranging from 1 to 3 g m-3. Health risk assessments revealed that the calculated chronic hazard quotient (HQ) for BC across the exposed groups was less than 1 (HQ < 1). Both sampling sites recorded cancer risk values exceeding the acceptable value of 1 x 10-6. This work provides a foundation of understanding BC pollution in the tropical region of Malaysia. Recognising the implications of BC on climate and health, Malaysia should establish BC monitoring efforts and give sufficient attention to evidence-based policies to reduce black carbon emissions.
How to cite: Binti Md Sofwan, N., Suhaimi, N. F., Mahidin, H., Ash'aari, Z. H., Yahaya, N. Z., and Alföldy, B.: Assessment of black carbon concentrations, emission sources and health risks in two cities of Peninsular Malaysia , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-974, https://doi.org/10.5194/egusphere-egu26-974, 2026.
Rapid urbanisation and rising vehicular emissions have become one of the major causes of declining air quality in the Himalayan foothill regions/cities. Black Carbon (BC), a short-lived climate pollutant primarily emitted due to the incomplete combustion of fossil fuels, biomass fuels, and open burning, is not only associated with atmospheric warming but also with adverse human health. In the present study, the spatial distribution of BC was assessed in Dehradun, the capital city of Uttarakhand state, India. Dehradun resides in the valley sandwiched between the Shiwalik range to the south and the Lesser Himalayan range to the north. In the present study, the integration of a comprehensive mobile and fixed-site monitoring approach has been applied to the assessment of BC in the region during 2022–2023. The microAeth MA350 was used for mobile monitoring, while the Aethalometer AE33 was used for fixed-site monitoring. Further, personal exposure to BC was evaluated to assess the spatial-temporal variation of human exposure to it along four different routes. The selected routes represented different microenvironments, including urban regions with heavy traffic, industrial regions, and green corridors. A total of ~100 hours of mobile monitoring was conducted. The mean BC concentration of 3.78 ± 3.01 µg/m³ at the fixed site was much lower than the mean BC concentration along the mobile-monitored routes, which varied from 18.09 ± 15.51 µg/m³ to 27.22 ± 17.90 µg/m³. For the determination of individual inhalation doses, three different respiratory rates (RRs) were used, indicating diverse commuting intensities in the region, viz. passive travel (0.47 m³/hr), walking (0.63 m³/hr), and cycling/motorcycling (0.70 m³/hr). It was realised that at the lowest RR, the total inhalation doses were estimated within the range of 10.08 µg to 14.06 µg, while at the highest RR, the inhalation doses ranged from 15.01 µg to 20.94 µg. However, during moderate activity levels, inhalation doses remained within the range of 13.51-18.84 µg. Whereas higher RR results in increased air intake, the inhalation dose of pollutants, such as BC, also increases with greater physical exertion. This pattern is evident for all routes, reinforcing the idea that physical exertion plays a crucial role in determining personal exposure levels. Individuals engaged in more physically demanding commuting modes, such as cycling or motorcycling, inhale more air per hour, which increases their intake of airborne pollutants. The inhalation dose shows a consistent increase with respiratory rate across all chosen routes, thereby indicating the impact of physical activity on pollutant intake. The preliminary results of this unique regional study emphasise the need to consider mobility patterns and the choice of path when determining pollutant exposure. This study also highlights the uncertainty and challenges associated with the estimation of BC concentrations within our environment. The present study is an initiative that may help in understanding and managing the urban air quality, thereby suggesting the importance of sustainable transportation strategies and public awareness initiatives aimed at reducing the health risks within the valley.
How to cite: Pandey, C. P., Shrivas, A., and Thakur, A.: Spatiotemporal Assessment of Black Carbon in the Urban Environment of Dun Valley, Himalayan Foothills, India, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22201, https://doi.org/10.5194/egusphere-egu26-22201, 2026.
Particulate matter, particularly PM₂.₅ continues to be a critical determinant of the global disease burden, underscoring the scale of exposure and the multifaceted processes through which it affects human health. In Pakistan, particularly the Punjab province, fast-growing urbanization and industrialization has dramatically intensified PM₂.₅ load, with many metropolitan cities consistently surpassing WHO air quality guidelines. This study aims to examine the persuasive relationship between PM₂.₅ exposure and associated health impacts across five major cities including Lahore, Faisalabad, Rawalpindi, Multan and Rahim Yar Khan. Integrating NASA MERRA-2 satellite derived PM₂.₅ data (January 2015–July 2025) with hospital health records, this study performed a time series epidemiological analysis to quantify the impact of PM₂.₅ on morbidity and mortality from respiratory, cardiovascular, and allergic diseases across multiple urban centers. Demographic factors including gender and age group have also been considered for evaluating vulnerable populations. Results indicate a positive correlation between escalating PM₂.₅ concentrations and respiratory (r = 0.33), cardiovascular (r = 0.46), and allergies (r = 0.44) diseases, with pediatric and older being more susceptible. Although significance dip in PM₂.₅ levels was observed during COVID-19 period, the disease incidence continued to surge with a little decline during lockdown months displaying just a short-term fluctuation. Findings underscore the pressing need for consolidated, data-driven approaches including strict air quality regulations, healthcare system strengthening and sustainable city development strategies. Ultimately, this study will contribute to the current understanding of environmental and public health, providing a foundation for future research and policy interventions aimed at safeguarding populations from the health impacts of particulate matter.
How to cite: Hina, S., Sana, A., Adrees, M., Noureen, S., and Zulfiqar, I.: Air Pollution and Public Health: A Multi-City Assessment of PM₂.₅ Exposure in Punjab, Pakistan, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-836, https://doi.org/10.5194/egusphere-egu26-836, 2026.
This study presents the concentration and speciation of VOCs over three high-altitude Himalayan glacier regions {Western Himalayan region (WHR; Thajiwas glacier, 2799 m asl), central Himalayan region (CHR; Gomukh glacier, 3415m asl) and eastern Himalayan region (EHR; Zemu glacier, 2700 m asl)} along with their comparison with those reported over Arctic and Antarctic glacier regions. 28 VOCs were determined in ambient air samples, collected in sorbent tubes using a ACTI -VOC low flow pump sampler, throughout the summer and winter periods of 2019-2020, followed by analysis using thermal desorption gas-chromatography mass spectrometry (TD-GC-MS/MS). The average sums of 28 VOCs were found to be 161.58 µg.m-3 at CHR, 120.73 µg.m-3 at EHR and 94.33 µg.m-3 at WHR. These values are found to be 4 to 40 fold and 0.8 to 2 fold higher than those reported over Arctic and Antarctic glaciers. On comparing these findings with those reported for an urban-industrial location of India (Raipur, Chhattisgarh) with similar period of measurement campaigns, a 2-fold lower concentration is observed over Himalayan glaciers. The results, also, indicated that CHR site has higher concentration of VOCs compared to other two sites WHR and EHR. Evaluation of seasonal variation pattern across the sites and source characterization by PMF5.0 were also made. UNMIX output of three-factor solution that explain >90% ambient VOC’s measurement is found to be similar to those of three source-factor solution from PMF5.0. The results revealed that three VOCs source types were: vehicle engine exhausts, biomass burning and coal combustion and biogenic emissions. The findings have important implications for appropriately assessing the effects of VOCs on glacial melting in high-altitude Himalayan glacier regions.
Keywords: Ambient VOCs, Seasonal variability; Himalayan glacier region, Source identification
How to cite: Tamrakar, A. and Pervez, S.: VOCs Over Himalayan Glaciers: Speciation, Sources and Comparison with Other Glaciers, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20727, https://doi.org/10.5194/egusphere-egu26-20727, 2026.
Urban environmental degradation in India’s metropolitan centres poses escalating challenges for public health, economic productivity, and sustainable urban governance. Among these regions, the National Capital Region (NCR) especially Delhi continues to be one of the most environmentally stressed urban agglomerations, experiencing chronic air pollution, deteriorating water quality. Although several domain-specific assessments exist, there remains a critical gap in developing an integrated and empirically grounded framework that jointly evaluates air, water, and captures their combined influence on urban environmental quality. This study fills that gap by constructing the Composite Environmental Quality Index – Air, Water (CEQI-AW) for Delhi, using 2022–23 as the base year (Index = 100). The index facilitates both monthly and annual comparisons of environmental quality from 2022–23 onward, drawing on publicly available real-time monitoring networks, administrative datasets, and spatial environmental information.
The framework consists of three pillars: Air Quality Index (AQI), Water Quality Index (WQI). Monthly data from April 2022 to March 2023 are used to construct the base-year composite index, and subsequent months up to the latest available period are incorporated for temporal trend analysis. Air quality indicators are sourced from Central Pollution Control Board (CPCB) and Delhi Pollution Control Committee (DPCC) continuous monitoring stations and include concentrations of PM₂.₅, PM₁₀, NO₂, SO₂, CO, and O₃. Water quality parameters are compiled from CPCB’s Yamuna monitoring network, Delhi Jal Board treatment plant reports, and Central Ground Water Board (CGWB) groundwater assessments, covering indicators such as BOD, COD, DO, TDS, fecal coliform, nitrate, fluoride, and heavy metals.
The study employs a hybrid weighting method: equal weights are assigned across the two pillars for transparency, and within each pillar, a simple geometric mean is used to construct item-level indices. The CEQI-AW is then computed for each year from the base year (2022–23) through 2024–25, enabling an assessment of inter-annual and seasonal variation.
Preliminary findings reveal that while some districts in Delhi show modest improvements in air quality during targeted winter interventions, environmental quality remains under significant strain. The year-on-year comparison for winter season (especially November, December and January) shows the highest variation in air quality in Delhi, driven by severe winter smog episodes and meteorological stagnation. Water quality exhibits distinct seasonal fluctuations, with the summer months (May and June) showing peak contamination until dilution and runoff effects during the monsoon lead to temporary improvement. Overall, the composite index exhibits an upward but uneven trajectory, heavily influenced by air quality volatility. The results highlight the need for season-specific policy interventions—winter mitigation for air pollution, summer strategies for water contamination, to effectively address environmental challenges in Delhi.
How to cite: Malick, B. K.: A Composite Environmental Quality Index: An Analysis of Air, Water (CEQI-AW) in Delhi from 2022 to 2025, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-909, https://doi.org/10.5194/egusphere-egu26-909, 2026.
In the Anthropocene, interactions between natural mineral dust and anthropogenic emissions have become a major driver of deteriorating air quality across the Indian subcontinent. While the Indo-Gangetic Plain (IGP) remains a persistent hotspot for fine-mode urban pollution, increasingly frequent and intense pre-monsoon dust storms now act as powerful amplifiers of existing aerosol burdens. This study presents a three-decade (1995–2025) spatiotemporal assessment of dust-storm dynamics using the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) reanalysis product, multi-sensor satellite observations including the Moderate Resolution Imaging Spectroradiometer (MODIS), Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), and ground-level Particulate Matter (PM) monitoring.
Across these three decades, all datasets show a systematic intensification of pre-monsoon dust activity, with percentage changes derived from contrasts between monthly means of the early decade (1995–2005) and the most recent decade (2015–2025). In May, Aerosol Optical Depth (AOD) increases by 26%, Dust Column Mass Density (DCMD) by 15%, and Ångström Exponent (AE) by 31%, indicating stronger dust uplift accompanied by enhanced mixing with fine anthropogenic particles. In comparison, June shows a modest rise in AOD (9%) and DCMD (~2%) with a smaller AE increase (14%), suggesting a gradual end of the peak dust-activity season in the IGP.
Using a three decades long dataset rather than a shorter record is crucial: two-decade comparisons masked the gradual shift in dust-storm timing and the emergence of mixed dust–pollution regimes, whereas the full 1995–2025 time frame reveals coherent, climatologically robust transitions. The results show that strengthening dust intrusions now interact with rapidly evolving urban emissions, modifying aerosol properties and elevating exposure risks. Accounting for these dust–pollution couplings is essential for realistic air-quality assessment and climate–health planning.
How to cite: Sharma, R. R., Jain, M., Bali, N. B., and Saxena, P.: Three decades of Dust Storm Dynamics in Thar Desert region of India: Evolving Aerosol Properties and Impacts on Urban Air Quality., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-687, https://doi.org/10.5194/egusphere-egu26-687, 2026.
Delhi, located within the Indo-Gangetic Plain (IGP), has undergone rapid urbanisation over the past few decades and today represents one of the most densely populated megacities, with nearly 40 million people in the wider National Capital Region regularly exposed to severe air-quality stress. Despite this significance, long-term ground-based CO2 measurements remain sparse, making Delhi a data-scarce environment for greenhouse-gas assessment. In such context, satellite observations offer an essential alternative for evaluating broad-scale CO₂ behaviour, particularly for cities lacking extensive monitoring networks.
This study examines the seasonal variability of column-averaged CO₂ (XCO₂) over Delhi using six years (2019–2024) of quality-filtered observations from NASA’s Orbiting Carbon Observatory-2 (OCO-2). To understand how XCO₂ evolves through the year, monthly values were compared against their multi-year averages, allowing us to identify recurring seasonal tendencies rather than year-specific fluctuations. Using this approach, the satellite data consistently show elevated CO₂ levels during the pre-monsoon months (April–June), followed by a noticeable reduction during the monsoon season, attributed to the precipitation-induced scavenging of CO₂, and increased vegetation growth. As winter approaches, XCO₂ begins to rise again, reflecting the influence of shallow boundary-layer height and larger wind-speed stagnation over northern India.
Delhi’s strong seasonal contrasts provide a clear setting for investigating how satellite-retrieved CO₂ responds to regional meteorology within a dense megacity. The patterns identified in this study highlight the capability of spaceborne observations to capture physically meaningful CO₂ dynamics even in complex, polluted urban environments. These findings also emphasise the value of publicly accessible satellite datasets for cities where continuous ground-based measurements are limited.
How to cite: Sharma, A., Jain, M., Yadav, A., and Saxena, P.: Satellite-Derived Seasonal CO₂ Dynamics Over a Northern Indian Megacity: OCO-2 Observations for Delhi (2019–2024), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-592, https://doi.org/10.5194/egusphere-egu26-592, 2026.
Urban ecosystems in megacities like Delhi are shaped by interactions between emissions, built structures, and seasonal meteorology, making policy evaluation vital for understanding environmental resilience and health risks. This study assesses the effectiveness of the Graded Response Action Plan (GRAP) which is Delhi’s tiered emergency framework that mandates escalating pollution-control measures during periods of severe air quality deterioration, across 2022-23, 2023-24, and 2024-25 by analysing high-resolution air quality variations at two contrasting urban settings; residential zone (Dwarka) and industrial cluster zone (Mundka). Multi-pollutant datasets (PM₂.₅, PM₁₀, NO₂, SO₂, CO, and O₃) were examined across Pre-, During-, and Post-GRAP periods to capture seasonal dynamics and ecosystem-specific responses.
Across all years, particulate pollution showed sharp winter escalation, with PM₂.₅ rising from 40–90 µg/m³ in the Pre-GRAP window (defined as the 45 days prior to GRAP enforcement) to 130–230 µg/m³ during-GRAP, and PM₁₀ increasing from 150–300 µg/m³ to 300–400 µg/m³, with maxima exceeding 600–800 µg/m³ at specific sites. GRAP which typically is implemented for 6 to 8 months each year depending on prevailing pollution levels, which was then evaluated using this ±45-day framework to capture baseline and recovery phases. These particulate levels far exceed WHO and national limits, posing severe respiratory and cardiovascular risks. NO₂ often doubled during GRAP (reaching 50–70 µg/m³), while O₃ showed expected winter suppression (<20 µg/m³) and strong post-winter recovery (30–50 µg/m³), clearly reflected in the 45-day Post-GRAP period. Unlike other pollutants, SO₂ showed inconsistent GRAP influence, increasing during-GRAP and decreasing post-GRAP, indicating a significant policy gap especially in industrial zone where sulfur emissions persist. This is concerning because SO₂ forms sulfate aerosols, contributing to secondary PM and amplifying health impacts.
Although pollutants declined post-GRAP, they rarely returned to Pre-GRAP baselines, especially at industrial sites. Findings show that GRAP mitigates extreme peaks but remains insufficient, underscoring the need for ecosystem-specific, year-round emission controls particularly targeting sulfur sources to strengthen urban environmental health.
How to cite: Singh, M., Sharma, R., Bali, R., and Saxena, P.: Synergistic Approach Towards the Implementation and Effectiveness of the Graded Response Action Plan (GRAP) on Air Quality in Delhi NCR, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-639, https://doi.org/10.5194/egusphere-egu26-639, 2026.
