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Extreme smog in India widely impacts air quality in late autumn and winter months. While the links between emissions, air quality and health impacts are well‐recognized, the association of smog and its intensification with climatic trends in the lower troposphere, where aerosol pollution and its radiative effects manifest, are not understood well. Here we use long‐term satellite data to show a significant increase in aerosol exceedances over northern India, resulting in sustained atmospheric warming and surface cooling trends over the last two decades. We find several lines of evidence suggesting these aerosol radiative effects have induced a multidecadal (1980–2019) strengthening of lower tropospheric stability and increase in relative humidity, leading to over fivefold increase in poor visibility days. Given this crucial aerosol‐radiation‐meteorological feedback driving the smog intensification, results from this study would help inform mitigation strategies supporting stronger region‐wide measures, which are critical for solving the smog challenge in India. Severe air pollution in India and its impacts on air quality and public health are worsening. Extreme smog episodes are frequently observed in northern India associated with the highest aerosol concentrations and hazardous visibility conditions. It is well‐known that anthropogenic emissions directly affect pollution, but it remains unclear from an observational perspective how the stability of the lower troposphere, where aerosol pollution builds up, impacts the long‐term evolution of smog. Using a multidecadal analysis of satellite, ground and reanalysis data sets, here we show sustained intensification of extreme smog associated with the strengthening of lower tropospheric stability, potentially amplified by aerosol‐induced atmospheric warming. Solving the smog crisis in India is increasingly critical given the strongly linked aerosol‐radiation‐meteorological interactions. Past 40‐year observations reveal aerosol‐induced radiation‐meteorological feedbacks have intensified extreme smog in India Past 40‐year observations reveal aerosol‐induced radiation‐meteorological feedbacks have intensified extreme smog in India

We examine the spatial and temporal trends of absorbing aerosol optical depth (AAOD) in the last decade over the United States (U.S.) observed by the Ozone Monitoring Instrument (OMI). Monthly average OMI AAOD has increased over broad areas of the central U.S. from 2005 to 2015, by up to a factor of 4 in some grid cells (~60?km resolution). The AAOD increases in all seasons, although the percentage increases are larger in summer (June-July-August) than in winter (December-January-February) by a factor of 3. Despite enhancements in AAOD, OMI AOD exhibits insignificant trend over most of the U.S. except parts of the central and western U.S., the latter which may partly be due to decreases in precipitation. Trends in AAOD contrast with declining trends in surface concentrations of black carbon (BC) aerosol. Interannual variability of local biomass burning emissions of BC may contribute to the positive trend in AAOD over the western U.S. Changes in both dust aerosol measured at the surface (in terms of concentration and size) and dust AAOD indicate distinct enhancements, especially over the central U.S. by 50–100%, which appears to be one of the major factors that impacts positive trends in AAOD. Significant positive trends of OMI AAOD in the U.S. over 2005–2015 are identifiedThe positive trends of AAOD are found not to be dominated with absorbing carbonaceous aerosols from U.S. anthropogenic local emissionsPositive trends of AAOD are partially associated with increasing concentrations of coarse dust

Frequent observations of aerosols from space are essential for studying aerosol effects on climate and air quality applications. We present results of aerosol properties derived from observations made by the Earth Polychromatic Imaging Camera (EPIC) sensor onboard the Deep Space Climate Observatory satellite. EPIC's near‐hourly measured radiances at 340 and 388 nm from sun rise to sunset have been used as input to the EPIC near‐UV aerosol algorithm (EPICAERUV) for retrieving aerosol extinction optical depth (AOD), single scattering albedo (SSA), above‐cloud aerosol optical depth (ACAOD), and ultraviolet Aerosol Index. Comparisons of AERONET and EPIC daily mean AOD values at eight selected representative sites yield correlation coefficients in the range from 0.68 to 0.89 and root mean square errors from 0.10 to 0.31. A similar comparison of EPIC‐retrieved SSA against the AERONET inverted SSA product revealed nearly 51% (76%) of matchups in agreement within ±0.03 (±0.05). Furthermore, the retrievals of ACAOD are also found to compare reasonably well, with 50%–70% of matchups falling within expected uncertainty against the direct airborne measurements acquired during the ObseRvations of Aerosols above CLouds and their intEractionS campaign. Using the EPICAERUV aerosol product, we analyzed the spatial and temporal patterns of specific smoke events caused by wildfires over North America over the last four years. Earth Polychromatic Imaging Camera (EPIC) retrieved aerosol optical depth, single scattering albedo, and above‐cloud aerosol optical depth agree well with ground‐based and airborne observations within expected uncertaintyEPIC contributed to the observational proof of smoke self‐lofting via the tropopause by solar‐absorption driven diabatic heating in 2017The smoke plumes coast‐to‐coast extent seen by EPIC in 2020 offers an insight of the efficiency of mixing processes in the free atmosphere Earth Polychromatic Imaging Camera (EPIC) retrieved aerosol optical depth, single scattering albedo, and above‐cloud aerosol optical depth agree well with ground‐based and airborne observations within expected uncertainty EPIC contributed to the observational proof of smoke self‐lofting via the tropopause by solar‐absorption driven diabatic heating in 2017 The smoke plumes coast‐to‐coast extent seen by EPIC in 2020 offers an insight of the efficiency of mixing processes in the free atmosphere