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To cut Delhi’s air pollution, pinpoint the source

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By Eric Dodge & Rohini Pande

This winter, Delhi’s government and the judiciary have implemented several policies aimed at cutting the national capital’s air pollution. The just-concluded odd-even scheme in the city required motorists to find alternative means of transportation every other day.

Car-free days, first in Gurgaon and then in Delhi, appeared to cause a temporary dip in pollution levels. The night hours when trucks can pass through Delhi have been reduced, and the National Green Tribunal has issued a direction to lower truck traffic coming into the city at night by levying an additional entrance fee.

On some days the air may be clearer. But what remains hazy is where Delhi’s air pollution comes from. Over the years, multiple attempts to find out – called source apportionment studies – have yielded contradictory results. There are numerous suspects: cars and trucks, smokestacks, farm fires in Punjab and Haryana, and dust from construction sites to name just a few. Without a better knowledge of the portion contributed by different sources, any policy response, no matter how bold, will be a little like a blind attempt to pin the tail on the donkey.

But that may be changing. The Indian Institute of Technology-Kanpur (IIT-K) has now released a major study, commissioned by the Delhi environment department in 2011. This promises to give the clearest picture of source apportionment yet. And other new sources of quality information on air pollution are appearing: the government has plans to add 10 new air quality monitoring stations in Delhi, and news outlets are setting up their own monitoring systems, including IndiaSpend #Breathe.

This could be a turning point in our understanding of the sources of Delhi’s deadly air, as well as our ability to craft smart policies that shut them down. We at Evidence for Policy Design (EPoD) are researchers who assist government ministries in formulating such responses. We think that at a time like this – a critical convergence of public concern, policymaker attention, and academic contribution – it’s worth taking stock of what we know now and how we came to know it. That clarity will make it easier to guide the discussion toward a policy response that will stick.

There are two ways of conducting source apportionment studies: direct sampling based on chemical analysis, and secondary data analysis based on monitoring data. The international best practice is to rely on receptor-based studies, but where budgetary constraints inhibit adequate sampling, analysis using secondary data may dominate.

Over the past 10 years, and excluding the just completed IIT-K study, we count 15 source apportionment studies that sought to pinpoint the sources of emissions and their respective contributions to Delhi’s overall air pollution. Ten are based on direct sampling; the other five rely on secondary data. While the main sources identified are similar across studies, the relative weights placed on different sources by these studies vary dramatically. This underscores both the difficulty of conducting them and the wide range in the quality of the studies currently available.

Getting a reliable picture of air pollution is inherently difficult due to Delhi’s changing weather conditions and constantly shifting patterns of emissions throughout the day, week, and year. Moreover, some of the most important pollution sources lie outside the National Capital Region. This makes it important that direct air sampling studies are broad enough to capture multiple sources and take samples at several different time points. An inability to do this-largely due to budgetary considerations-and the resulting differences in what gets sampled are an important part of the explanation for the large differences across studies.

In such situations, secondary data-based analysis may well be the best option for source apportionment studies, as long as these secondary sources are reliable and span relevant emission sources. Right now, we lack a measure of whether that is the case. Without standardized best practices about which secondary data sources to use and which model to use, source apportionment studies will continue to give conflicting results going forward.

So, we not only lack the best information on pollution, we also lack consensus on how to determine the second best. (IANS/IndiaSpend.org) (Photo: social.yourstory.com)

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Youth in polluted cities at increased risk of Alzheimer’s

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Climate Trends works on solutions to air pollution, while Co Media Lab is a community media lab.
Pollution can lead to Alzheimer's in youth. Wikimedia Commons

Children and young adults living in polluted megacities are at increased risk of developing Alzheimer’s, a debilitating brain disease characterised by memory loss, a new study has warned.

“Alzheimer’s disease hallmarks start in childhood in polluted environments, and we must implement effective preventative measures early,” said one of the researchers Lilian Calderon-Garciduenas from University of Montana in the US.

Air pollution can trigger Alzheimer’s. Flickr

“It is useless to take reactive actions decades later,” Calderon-Garciduenas said. The findings, published in the Journal of Environmental Research, indicate that Alzheimer’s starts in early childhood, and the disease progression relates to age, pollution exposure and status of Apolipoprotein E (APOE 4), a well-known genetic risk factor for Alzheimer’s. The researchers studied 203 autopsies of Mexico City residents in the US ranging in age from 11 months to 40 years.

Metropolitan Mexico City is home to 24 million people exposed daily to concentrations of fine particulate matter and ozone above US Environmental Protection Agency standards. The researchers tracked two abnormal proteins that indicate development of Alzheimer’s, and they detected the early stages of the disease in babies less than a year old.

Also Read: Your daily cup of coffee can worsen Alzheimer’s symptoms

The scientists found heightened levels of the two abnormal proteins — hyperphosphorylated tau and beta amyloid — in the brains of young urbanites with lifetime exposures to fine-particulate-matter pollution (PM2.5).

They also tracked APOE 4 as well as lifetime cumulative exposure to unhealthy levels of PM2.5 — particles which are at least 30 times smaller than the diameter of a human hair and frequently cause the haze over urban areas. The researchers found hallmarks of the disease among 99.5 percent of the autopsies they examined in Mexico City. In addition, the findings showed that APOE 4 carriers had a higher risk of rapid progression of Alzheimer’s.

Alzheimer’s can cause depression too. Pixabay

The researchers believe the detrimental effects are caused by tiny pollution particles that enter the brain through the nose, lungs and gastrointestinal tract, and these particles damage all barriers and travel everywhere in the body through the circulatory system.

The authors noted that ambient air pollution is a key modifiable risk for millions of people across the globe. “Neuroprotection measures ought to start very early, including the prenatal period and childhood,” Calderon-Garciduenas said. “Defining pediatric environmental, nutritional, metabolic and genetic risk-factor interactions are key to preventing Alzheimer’s disease,” she added. IANS