New directions: Air pollution challenges for developing megacities like Delhi

Size–segregated particulate matter inside residences of elderly in the Metropolitan Area of São Paulo, Brazil

“…All these measurements were made during the days when there was precipitation. The cluster 3 has the residences with more coarse particles (stage A) than the other PM sizes, mainly due to wind speed being higher during the measurements that would have favoured the resuspension of coarse particles (Harrison et al, 2001;Kumar et al, 2015). The cluster 4 has the same profile like as the cluster 1, but with less mass concentration, whereas the cluster 5 has a different profile with the maximum concentrations in PM 0.5-0.25 (stage D).…”

Study of Local and Regional Influence on PM2.5 Concentration during Odd-Even Rule in Delhi Using Causal Analysis

“…This is particularly observed for the neighbouring locations from SE and SW sector. The contribution of dust from surrounding areas is reported in many studies (Marrapu, 2012;Chelani, 2013;Kumar et al, 2015). In addition to the local sources, regional pollution therefore also influences the PM 2.5 levels in Delhi.…”

“…Diesel and gasoline based cars, private vehicles, heavy duty vehicles, Compressed Natural Gas (CNG) based public transport vehicles, utility vehicles and metro rail define the transportation system in the city (Pant et al, 2015). In-spite of the several control measures including EURO III and EURO IV norms incorporated to curb the pollution levels, Delhi has not yet witnessed a decline in the air pollutant concentrations (Kumar et al, 2015). There is continuous uproar at public and political level on the rising air pollution levels.…”

“…Trajectory clustering and concentrationweighted trajectory showed the significant contribution of these areas to aerosol concentrations in the Delhi region. A more rigorous study and review on the air pollution problem in Delhi is given in a recent study by Kumar et al (2015).…”

Climate and atmospheric science: raising the temperature

“…The determinants of concentrations of fine particulate matter and ozone are a complex function of atmospheric dynamics and atmospheric chemistry, and the scientific community still has much work to do to develop an adequate predictive capability for future concentrations as mitigation measures are developed. Cities such as Delhi 11 and Beijing have huge problems of air pollution, which are linked to both meteorology and atmospheric chemistry, and research is revealing new mechanisms of particle formation. 12 There are similar questions over stratospheric ozone and the recovery of the ozone layer, which requires an understanding of the complex coupling of ozone, atmospheric chemistry, transport and climate.…”