Fine particulate matter (PM2.5) association with peripheral artery disease admissions in northeastern United States.

BACKGROUND: Current evidence, on the association of PM2.5 and peripheral artery disease (PAD) is very sparse. METHODS: We use novel PM2.5 prediction models to investigate associations between chronic and acute PM2.5 exposures and hospital PAD admissions across the northeast USA. Poisson regression analysis was preformed where daily admission counts in each zip code are regressed against both chronic and acute PM2.5 exposure, temperature, socio-economic characteristics and time to control for seasonal patterns. RESULTS: Positive significant associations were observed between both chronic and acute exposure to PM2.5 and PAD hospitalizations. Every 10-µg/m(3) increase in acute PM2.5 exposure was associated with a 0.26 % increase in admissions (CI = 0.08 - 0.45 %) and every 10-µg/m(3) increase in chronic PM 2.5 exposure was associated with a 4.4 % increase in admissions (CI = 3.50 - 5.35 %). CONCLUSIONS: The study supports the hypothesis that acute and chronic exposure to PM2.5 can increase the risk of PAD.

COVID-19's lockdown effect on air quality in Indian cities using air quality zonal modeling.

The complete lockdown due to COVID-19 pandemic has contributed to the improvement of air quality across the countries particularly in developing countries including India. This study aims to assess the air quality by monitoring major atmospheric pollutants such as AOD, CO, PM2.5, NO2, O3 and SO2 in 15 major cities of India using Air Quality Zonal Modeling. The study is based on two different data sources; (a) grid data (MODIS- Terra, MERRA-2, OMI and AIRS, Global Modeling and Assimilation Office, NASA) and (b) ground monitoring station data provided by Central Pollution Control Board (CPCB) / State Pollution Control Board (SPCB). The remotely sensed data demonstrated that the concentration of PM2.5 has declined by 14%, about 30% of NO2 in million-plus cities, 2.06% CO, SO2 within the range of 5 to 60%, whereas the concentration of O3 has increased by 1 to 3% in majority of cities compared with pre lockdown. On the other hand, CPCB/SPCB data showed more than 40% decrease in PM2.5 and 47% decrease in PM10 in north Indian cities, more than 35% decrease in NO2 in metropolitan cities, more than 85% decrease in SO2 in Chennai and Nagpur and more than 17% increase in O3 in five cities amid 43 days pandemic lockdown. The restrictions of anthropogenic activities have substantial effect on the emission of primary atmospheric pollutants.

Temporary reduction in fine particulate matter due to 'anthropogenic emissions switch-off' during COVID-19 lockdown in Indian cities.

The COVID-19 pandemic elicited a global response to limit associated mortality, with social distancing and lockdowns being imposed. In India, human activities were restricted from late March 2020. This 'anthropogenic emissions switch-off' presented an opportunity to investigate impacts of COVID-19 mitigation measures on ambient air quality in five Indian cities (Chennai, Delhi, Hyderabad, Kolkata, and Mumbai), using in-situ measurements from 2015 to 2020. For each year, we isolated, analysed and compared fine particulate matter (PM2.5) concentration data from 25 March to 11 May, to elucidate the effects of the lockdown. Like other global cities, we observed substantial reductions in PM2.5 concentrations, from 19 to 43% (Chennai), 41-53% (Delhi), 26-54% (Hyderabad), 24-36% (Kolkata), and 10-39% (Mumbai). Generally, cities with larger traffic volumes showed greater reductions. Aerosol loading decreased by 29% (Chennai), 11% (Delhi), 4% (Kolkata), and 1% (Mumbai) against 2019 data. Health and related economic impact assessments indicated 630 prevented premature deaths during lockdown across all five cities, valued at 0.69 billion USD. Improvements in air quality may be considered a temporary lockdown benefit as revitalising the economy could reverse this trend. Regulatory bodies must closely monitor air quality levels, which currently offer a baseline for future mitigation plans.