Ultrafine particles in cities

Abstract

Ultrafine particles (UFPs; diameter less than 100 nm) are ubiquitous in urban air, and an acknowledged risk to human health. Globally, the major source for urban outdoor UFP concentrations is motor traffic. Ongoing trends towards urbanisation and expansion of road traffic are anticipated to further increase population exposure to UFPs. Numerous experimental studies have characterised UFPs in individual cities, but an integrated evaluation of emissions and population exposure is still lacking. Our analysis suggests that the average exposure to outdoor UFPs in Asian cities is about four-times larger than that in European cities but impacts on human health are largely unknown. This article reviews some fundamental drivers of UFP emissions and dispersion, and highlights unresolved challenges, as well as recommendations to ensure sustainable urban development whilst minimising any possible adverse health impacts.

Assessment of long-term measurements of particulate matter and gaseous pollutants in South-East Mediterranean

“…Our temporal trends of NOx and PM 10 concentrations are found to be similar with other results reported by Harrison et al (2008) where in the last decade, NOx and PM 10 concentrations are observed not to exhibit any falling trend in Europe, even if exhaust emissions standards and stationary sources regulations become tighter (Harrison, 2004;Kumar et al, 2014b). Therefore, the question being raised is whether current knowledge on source apportionment of criteria pollutants is sufficient and whether European agencies are provided with appropriate tools for the protection of human health.…”

The rise of low-cost sensing for managing air pollution in cities

“…A recent 'Global Burden of Disease' study has provided new evidence of the significant role that air pollution plays globally, placing it among the top ten risks faced by human beings (Lim et al 2012). Many of the world's cities are unable to comply with the prescribed concentration limits of air pollutants Sharma et al 2013), and in many cases, reported measurements far exceed them, resulting in millions of premature deaths (Kumar et al 2014b;Lim et al 2012;White et al 2012). At the forefront of pollutants which exceed concentration limits are coarse (PM 10 ) and fine particulate matter (PM 2.5 ), and unregulated ultrafine particles (<100 nm) (Kittelson et al 2004), making this issue even more complex (Heal et al 2012).…”

“…Similar estimates for PM 2.5 suggest an 6 average loss of 7-8 months in life expectancy for UK residents and about £20 billion per year in corresponding health costs (Defra 2008). An equivalent estimate for exposure to ultrafine particles, which have a greater potential for adverse health impacts compared to their larger counterparts (HEI 2013;WHO 2013), is currently unavailable, but will further increase the health and economic burden in the UK and elsewhere (Kumar et al 2014b). …”

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

“…The highest RDD difference was found in PM <0.25 which represented almost 29% and 17.2% higher deposition in males for seated and light exercise positions, respectively. This finding is concerning since these smaller particles show harmful effects on the human health compared with more coarse particles (Heal et al, 2012;Kumar et al, 2014;Han et al, 2016) and can favour deposition of endotoxin in pulmonary alveoli (Padhi et al, 2016).…”

“…The inhalable fraction of PM, which is PM 10 , can be divided into coarse (PM 2.5-10 ) and fine particles (PM 2.5 ). The fine particles also contain particles below 100 nm, which are referred to as ultrafine particles, PM 0.1 (Kumar et al, 2014;Seinfeld and Pandis, 2016). The ultrafine particles are known to have much greater health impacts than their larger counterparts (Martins et al, 2010;Kumar et al, 2011).…”